chore: remove empty tests that covered 0% of codebase

Vendored 5 packages from iOpenPod (TheRealSavi/iOpenPod):
  iTunesDB_Writer/  — binary iTunesDB generation
  iTunesDB_Shared/  — field defs, constants, album identity
  SQLiteDB_Writer/  — SQLite databases for Nano 6G/7G
  iTunesDB_Parser/  — play stats reading from iPod
  ipod_device/      — device detection, FireWire ID, capabilities

Rationale: iOpenPod is a standalone iPod manager app, not a library.
Pulling it as a pip dependency is heavy and confusing for users.

Changes:
  + src/vendor/   — 77 .py files + calcHashAB.wasm (506 KB)
  ~ ipod_nano7_db.py  — _find_iop_root() now returns src/vendor/
  ~ requirements.txt   — iopenpod replaced with wasmtime + pycryptodome
  ~ .gitignore         — removed iOpenPod/ exclusion
  (setup.py reads requirements.txt automatically)

.gitignore

@@ -37,4 +37,3 @@ converted/
 specs.md
 *.AppImage
 squashfs-root/
-iOpenPod/

README.md

@@ -1,13 +1,13 @@
 # neo-pod-desktop
 
-Настольное приложение для управления музыкой на iPod Nano 6G/7G с встроенным iTunes-подобным плеером, конвертацией аудио, полным пайплайном обложек и генерацией iTunesDB/SQLite/ArtworkDB через iOpenPod.
+Настольное приложение для управления музыкой на iPod Nano 7G с встроенным iTunes-подобным плеером, конвертацией аудио, полным пайплайном обложек и генерацией iTunesDB/SQLite/ArtworkDB.
 
 ## Возможности
 
 - **Встроенный плеер** — воспроизведение локальной библиотеки через QMediaPlayer, отображение обложек альбомов (60x60), перемотка, громкость, повтор (all/one), shuffle
 - **Конвертация аудио** — FFmpeg конвертация в AAC/M4A (libfdk_aac с AAC-LC профилем, 160 kbps) и MP3 (libmp3lame); конвертация видео для iPod (H.264, 640x480)
 - **Пайплайн ArtworkDB** — извлечение обложек из аудиофайлов (APIC/covr/FLAC pictures), кодирование в iPod-нативные форматы (RGB565, RGB555, UYVY, JPEG), запись ithmb + ArtworkDB (MHFD→MHII→MHNI структуры)
-- **Генерация баз iPod** — полная регенерация iTunesDB (бинарный mhbd) и SQLite баз для Nano 6G/7G через iOpenPod, cross-reference валидация db_pid
+- **Генерация баз iPod** — полная регенерация iTunesDB (бинарный mhbd) и SQLite баз для Nano 7G, cross-reference валидация db_pid
 - **Синхронизация статистики** — двухсторонняя синхронизация play count, rating, skip count, last played между локальным кэшем (SQLite) и iPod; автосинк при подключении; validation gate против потери данных
 - **Локальная библиотека** — сортируемая таблица с поддержкой drag-and-drop, фильтрация по альбомам/плейлистам, поиск, разделение на source-треки (FLAC/WAV) и готовые (MP3/M4A)
 - **Плейлисты** — создание, переименование, удаление, drag-and-drop треков; перенос плейлистов на iPod с двухпроходным сопоставлением (content hash → metadata fallback)
@@ -112,7 +112,7 @@ neo-pod-desktop/
 | Технология | Назначение |
 |---|---|
 | **PyQt6** | Графический интерфейс, QMediaPlayer, сигналы/слоты |
-| **iOpenPod** | Генерация iTunesDB + SQLite + ArtworkDB для iPod Nano 6G/7G |
+| **iOpenPod (vendored)** | Генерация iTunesDB + SQLite + ArtworkDB для iPod Nano 7G |
 | **FFmpeg** | Конвертация аудио (AAC/MP3) и видео (H.264) |
 | **mutagen / eyeD3** | Чтение и запись метаданных (ID3, MP4, FLAC, OGG) |
 | **NumPy + Pillow** | Кодирование обложек (RGB565, масштабирование) |

requirements.txt

@@ -6,4 +6,5 @@ pillow>=9.5.0
 requests>=2.28.2
 PyQt6>=6.5.0
 numpy>=1.24.0
-iopenpod>=1.0.53
+wasmtime>=30.0.0
+pycryptodome>=3.20.0

src/ipod_nano7_db.py

@@ -40,31 +40,13 @@ from mutagen.easyid3 import EasyID3
 from artwork import prepare_artwork_for_track, ArtworkEntry, write_artworkdb
 
 def _find_iop_root() -> str:
-    """Find iOpenPod's installed location.
-
-    Tries in order:
-    1. pip-installed package (via importlib.util.find_spec)
-    2. /tmp/iOpenPod (backward compat / development)
-    """
-    for pkg in ("iTunesDB_Writer", "SQLiteDB_Writer", "ipod_device"):
-        spec = importlib.util.find_spec(pkg)
-        if spec and spec.origin:
-            parent = os.path.dirname(spec.origin)
-            if os.path.basename(parent) == pkg:
-                return os.path.dirname(parent)
-
-    fallbacks = [
-        os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "iOpenPod"),
-        "/tmp/iOpenPod",
-        os.path.join(os.path.expanduser("~"), "iOpenPod"),
-    ]
-    for path in fallbacks:
-        if os.path.isdir(path):
-            return path
-
-    raise ImportError(
-        "iOpenPod not found. Install with: pip install iopenpod"
-    )
+    """Return the vendored iOpenPod packages path."""
+    vendor_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "vendor")
+    if not os.path.isdir(vendor_path):
+        raise ImportError(
+            "iOpenPod vendor packages not found at %s" % vendor_path
+        )
+    return vendor_path
 
 _IOP_ROOT = _find_iop_root()
 _IOP_CACHE: dict[str, Any] = {}

src/vendor/SQLiteDB_Writer/__init__.py

@@ -0,0 +1,21 @@
+"""SQLiteDB_Writer — Write SQLite databases for iPod Nano 6G/7G.
+
+These iPods ignore the traditional binary iTunesDB (or iTunesCDB) and read
+music metadata from SQLite databases located in:
+
+    /iPod_Control/iTunes/iTunes Library.itlp/
+
+The directory contains:
+    Library.itdb     — tracks, albums, artists, composers, playlists, genres
+    Locations.itdb   — iPod file paths for each track
+    Dynamic.itdb     — play counts, ratings, bookmarks
+    Extras.itdb      — lyrics, chapters (optional, can be empty)
+    Genius.itdb      — genius data (optional, can be empty)
+    Locations.itdb.cbk — HASHAB-signed block checksums of Locations.itdb
+
+Reference implementation: libgpod itdb_sqlite.c
+"""
+
+from .sqlite_writer import write_sqlite_databases
+
+__all__ = ["write_sqlite_databases"]

src/vendor/SQLiteDB_Writer/_helpers.py

@@ -0,0 +1,64 @@
+"""Shared helpers for SQLiteDB_Writer modules.
+
+Centralises utilities that were previously duplicated across
+library_writer, locations_writer, dynamic_writer, extras_writer,
+and genius_writer.
+"""
+
+import os
+import sqlite3
+
+# ── Timestamp helpers ──────────────────────────────────────────────────
+# SQLite databases use Core Data timestamps: seconds since 2001-01-01 UTC
+# (the Cocoa/Core Foundation reference date).
+CORE_DATA_EPOCH = 978307200  # Unix timestamp of 2001-01-01 00:00:00 UTC
+
+
+def unix_to_coredata(unix_ts: int, tz_offset: int = 0) -> int:
+    """Convert Unix timestamp to Core Data timestamp.
+
+    Args:
+        unix_ts: Unix timestamp (seconds since 1970-01-01)
+        tz_offset: Timezone offset in seconds (positive = east of UTC)
+
+    Returns:
+        Core Data timestamp (seconds since 2001-01-01) adjusted for timezone.
+        Returns 0 if input is 0.
+    """
+    if unix_ts == 0:
+        return 0
+    return unix_ts - CORE_DATA_EPOCH - tz_offset
+
+
+def s64(val: int) -> int:
+    """Convert unsigned 64-bit int to signed for SQLite INTEGER storage.
+
+    SQLite INTEGER is signed 64-bit (max 2^63-1).  iPod db_ids and PIDs
+    are unsigned 64-bit values that may exceed this limit.
+    """
+    if val >= (1 << 63):
+        return val - (1 << 64)
+    return val
+
+
+def open_db(path: str, extra_pragmas: list[str] | None = None) -> tuple[sqlite3.Connection, sqlite3.Cursor]:
+    """Create a fresh SQLite database at *path*.
+
+    Deletes any existing file, opens a new connection with performance
+    PRAGMAs (journal_mode=OFF, synchronous=OFF), and returns (conn, cursor).
+
+    Args:
+        path: Output file path.
+        extra_pragmas: Additional PRAGMA statements to execute
+                       (e.g. ``["encoding='UTF-8'"]``).
+    """
+    if os.path.exists(path):
+        os.remove(path)
+
+    conn = sqlite3.connect(path)
+    conn.execute("PRAGMA journal_mode=OFF")
+    conn.execute("PRAGMA synchronous=OFF")
+    for pragma in extra_pragmas or []:
+        conn.execute(f"PRAGMA {pragma}")
+
+    return conn, conn.cursor()

src/vendor/SQLiteDB_Writer/cbk_writer.py

@@ -0,0 +1,171 @@
+"""Locations.itdb.cbk writer — HASHAB-signed block checksums.
+
+The cbk (checksum book) file contains SHA1 checksums of 1024-byte blocks
+of Locations.itdb, plus a final SHA1 of all those checksums, signed with
+HASHAB.
+
+File format:
+    [57 bytes]  HASHAB signature of final_sha1 (or 20 bytes for HASH58/72)
+    [20 bytes]  final_sha1 = SHA1(all_block_sha1s concatenated)
+    [Nx20 bytes] SHA1 of each 1024-byte block of Locations.itdb
+
+For HASHAB (Nano 6G/7G), the header is 57 bytes.
+For HASH58, the header would be 20 bytes.
+For HASH72, the header would be 46 bytes.
+
+Reference: libgpod itdb_sqlite.c mk_Locations_cbk()
+"""
+
+import hashlib
+import logging
+import os
+
+from ipod_device import ChecksumType
+
+logger = logging.getLogger(__name__)
+
+# Block size for checksumming
+BLOCK_SIZE = 1024
+
+
+def _compute_block_sha1s(data: bytes) -> list[bytes]:
+    """Compute SHA1 hash of each 1024-byte block.
+
+    The last block may be smaller than 1024 bytes; it's still hashed.
+
+    Args:
+        data: Raw file contents.
+
+    Returns:
+        List of 20-byte SHA1 digests, one per block.
+    """
+    block_hashes = []
+    offset = 0
+    while offset < len(data):
+        block = data[offset:offset + BLOCK_SIZE]
+        block_hashes.append(hashlib.sha1(block).digest())
+        offset += BLOCK_SIZE
+    return block_hashes
+
+
+def write_locations_cbk(
+    cbk_path: str,
+    locations_itdb_path: str,
+    checksum_type: ChecksumType,
+    firewire_id: bytes | None = None,
+    ipod_path: str | None = None,
+) -> None:
+    """Generate and write the Locations.itdb.cbk checksum file.
+
+    Args:
+        cbk_path: Output path for the .cbk file.
+        locations_itdb_path: Path to the Locations.itdb file to checksum.
+        checksum_type: The device's checksum algorithm (HASHAB, HASH58, etc.).
+        firewire_id: 8-byte FireWire GUID (required for HASHAB and HASH58).
+        ipod_path: Mount point of iPod (used for HASH72 HashInfo fallback).
+
+    Raises:
+        ValueError: If firewire_id is missing when needed.
+        FileNotFoundError: If Locations.itdb doesn't exist.
+    """
+    with open(locations_itdb_path, 'rb') as f:
+        locations_data = f.read()
+
+    # Compute block SHA1s
+    block_sha1s = _compute_block_sha1s(locations_data)
+
+    # Compute final SHA1 = SHA1(concatenation of all block SHA1s)
+    all_sha1s = b''.join(block_sha1s)
+    final_sha1 = hashlib.sha1(all_sha1s).digest()
+
+    logger.debug("Locations.itdb: %d bytes, %d blocks, final SHA1: %s",
+                 len(locations_data), len(block_sha1s), final_sha1.hex())
+
+    # Generate header signature based on checksum type
+    if checksum_type == ChecksumType.HASHAB:
+        if not firewire_id or len(firewire_id) < 8:
+            raise ValueError("FireWire ID required for HASHAB cbk signature")
+
+        from iTunesDB_Writer.hashab import compute_hashab
+        header = compute_hashab(final_sha1, firewire_id[:8])
+        if len(header) != 57:
+            raise RuntimeError(f"HASHAB returned {len(header)} bytes, expected 57")
+        logger.debug("CBK header: HASHAB signature (%d bytes)", len(header))
+
+    elif checksum_type == ChecksumType.HASH58:
+        if not firewire_id or len(firewire_id) < 8:
+            raise ValueError("FireWire ID required for HASH58 cbk signature")
+
+        from iTunesDB_Writer.hash58 import compute_hash58
+        header = compute_hash58(firewire_id, final_sha1)
+        logger.debug("CBK header: HASH58 signature (%d bytes)", len(header))
+
+    elif checksum_type == ChecksumType.HASH72:
+        from iTunesDB_Writer.hash72 import (
+            read_hash_info, extract_hash_info_to_dict,
+            _hash_generate, HashInfo,
+        )
+
+        # Try centralized store first
+        hash_info = None
+        try:
+            from ipod_device import get_current_device
+            dev = get_current_device()
+            if dev and dev.hash_info_iv and dev.hash_info_rndpart:
+                hash_info = HashInfo(
+                    uuid=b'\x00' * 20,
+                    rndpart=dev.hash_info_rndpart,
+                    iv=dev.hash_info_iv,
+                )
+        except Exception:
+            pass
+
+        if hash_info is None and ipod_path:
+            try:
+                hash_info = read_hash_info(ipod_path)
+            except Exception:
+                pass
+
+        # Fallback: extract from existing iTunesCDB on device
+        if hash_info is None and ipod_path:
+            try:
+                from ipod_device import resolve_itdb_path
+                itdb_path = resolve_itdb_path(ipod_path)
+                if itdb_path:
+                    with open(itdb_path, "rb") as f:
+                        itdb_data = f.read()
+                    hd = extract_hash_info_to_dict(itdb_data)
+                    if hd:
+                        hash_info = HashInfo(
+                            uuid=b'\x00' * 20,
+                            rndpart=hd['rndpart'],
+                            iv=hd['iv'],
+                        )
+                        logger.debug("CBK: extracted HashInfo from existing %s",
+                                     os.path.basename(itdb_path))
+            except Exception:
+                pass
+
+        if hash_info:
+            header = _hash_generate(final_sha1, hash_info.iv, hash_info.rndpart)
+            logger.debug("CBK header: HASH72 signature (%d bytes)", len(header))
+        else:
+            logger.warning("No HashInfo available for HASH72 cbk — writing final SHA1 only")
+            header = final_sha1
+
+    else:
+        # No checksum needed — older devices or NONE
+        # Just write the SHA1 as header (20 bytes)
+        header = final_sha1
+
+    # Write the cbk file: header + final_sha1 + block_sha1s
+    with open(cbk_path, 'wb') as f:
+        f.write(header)
+        f.write(final_sha1)
+        for bsha1 in block_sha1s:
+            f.write(bsha1)
+
+    total_size = len(header) + 20 + len(block_sha1s) * 20
+    logger.info("Wrote Locations.itdb.cbk: %d bytes "
+                "(%d-byte header + 20-byte final SHA1 + %d×20 block SHA1s)",
+                total_size, len(header), len(block_sha1s))

src/vendor/SQLiteDB_Writer/dynamic_writer.py

@@ -0,0 +1,124 @@
+"""Dynamic.itdb writer — play counts, ratings, and bookmark data.
+
+Contains item_stats (per-track play/skip counts, ratings, bookmarks)
+and container_ui (playlist UI state like play order, repeat, shuffle).
+
+Reference: libgpod itdb_sqlite.c mk_Dynamic()
+"""
+
+import logging
+from typing import Optional
+
+from iTunesDB_Writer.mhit_writer import TrackInfo
+from ._helpers import s64 as _s64, unix_to_coredata, open_db
+
+logger = logging.getLogger(__name__)
+
+
+_DYNAMIC_SCHEMA = """
+CREATE TABLE IF NOT EXISTS item_stats (
+    item_pid INTEGER NOT NULL,
+    has_been_played INTEGER DEFAULT 0,
+    date_played INTEGER DEFAULT 0,
+    play_count_user INTEGER DEFAULT 0,
+    play_count_recent INTEGER DEFAULT 0,
+    date_skipped INTEGER DEFAULT 0,
+    skip_count_user INTEGER DEFAULT 0,
+    skip_count_recent INTEGER DEFAULT 0,
+    bookmark_time_ms REAL,
+    bookmark_time_ms_common REAL,
+    user_rating INTEGER DEFAULT 0,
+    user_rating_common INTEGER DEFAULT 0,
+    rental_expired INTEGER DEFAULT 0,
+    play_count_user_original INTEGER DEFAULT 0,
+    skip_count_user_original INTEGER DEFAULT 0,
+    genius_id INTEGER DEFAULT 0,
+    PRIMARY KEY (item_pid)
+);
+
+CREATE TABLE IF NOT EXISTS container_ui (
+    container_pid INTEGER NOT NULL,
+    play_order INTEGER DEFAULT 0,
+    is_reversed INTEGER DEFAULT 0,
+    album_field_order INTEGER DEFAULT 0,
+    repeat_mode INTEGER DEFAULT 0,
+    shuffle_items INTEGER DEFAULT 0,
+    has_been_shuffled INTEGER DEFAULT 0,
+    PRIMARY KEY (container_pid)
+);
+
+CREATE TABLE IF NOT EXISTS rental_info (
+    item_pid INTEGER NOT NULL,
+    rental_date_started INTEGER DEFAULT 0,
+    rental_duration INTEGER DEFAULT 0,
+    rental_playback_date_started INTEGER DEFAULT 0,
+    rental_playback_duration INTEGER DEFAULT 0,
+    is_demo INTEGER DEFAULT 0,
+    PRIMARY KEY (item_pid)
+);
+"""
+
+
+def write_dynamic_itdb(
+    path: str,
+    tracks: list[TrackInfo],
+    playlist_pids: Optional[list[int]] = None,
+    tz_offset: int = 0,
+) -> None:
+    """Write Dynamic.itdb SQLite database.
+
+    Args:
+        path: Output file path.
+        tracks: List of TrackInfo objects.
+        playlist_pids: All playlist PIDs (master + user + smart), as returned
+                       by ``write_library_itdb()``.  One ``container_ui`` row
+                       is written per PID.
+        tz_offset: Timezone offset in seconds.
+    """
+    conn, cur = open_db(path)
+
+    cur.executescript(_DYNAMIC_SCHEMA)
+
+    # ── item_stats ─────────────────────────────────────────────────────
+    for track in tracks:
+        has_been_played = 1 if track.play_count > 0 else 0
+
+        date_played = unix_to_coredata(track.last_played or 0, tz_offset)
+        date_skipped = unix_to_coredata(track.last_skipped or 0, tz_offset)
+
+        cur.execute(
+            """INSERT INTO item_stats (
+                item_pid, has_been_played, date_played,
+                play_count_user, play_count_recent,
+                date_skipped, skip_count_user, skip_count_recent,
+                bookmark_time_ms, bookmark_time_ms_common,
+                user_rating, user_rating_common,
+                rental_expired,
+                play_count_user_original, skip_count_user_original,
+                genius_id
+            ) VALUES (?, ?, ?, ?, 0, ?, ?, 0, ?, ?, ?, ?, 0, ?, ?, 0)""",
+            (
+                _s64(track.db_track_id), has_been_played, date_played,
+                track.play_count,
+                date_skipped, track.skip_count,
+                float(track.bookmark_time), float(track.bookmark_time),
+                track.rating, track.app_rating,
+                track.play_count, track.skip_count,
+            )
+        )
+
+    # ── container_ui ───────────────────────────────────────────────────
+    # One row per playlist PID (master + user + smart)
+    for pid in (playlist_pids or []):
+        cur.execute(
+            "INSERT INTO container_ui (container_pid, play_order, is_reversed, "
+            "album_field_order, repeat_mode, shuffle_items, has_been_shuffled) "
+            "VALUES (?, 0, 0, 1, 0, 0, 0)",
+            (_s64(pid),)
+        )
+
+    conn.commit()
+    conn.close()
+
+    logger.info("Wrote Dynamic.itdb: %d item_stats, %d container_ui",
+                len(tracks), len(playlist_pids or []))

src/vendor/SQLiteDB_Writer/extras_writer.py

@@ -0,0 +1,82 @@
+"""Extras.itdb writer — lyrics and chapter data.
+
+Creates the Extras.itdb with empty tables. Lyrics from tracks are
+inserted if available.
+
+Reference: libgpod itdb_sqlite.c mk_Extras()
+"""
+
+import logging
+
+from iTunesDB_Writer.mhit_writer import TrackInfo
+from ._helpers import s64 as _s64, open_db
+
+logger = logging.getLogger(__name__)
+
+
+_EXTRAS_SCHEMA = """
+CREATE TABLE IF NOT EXISTS chapter (
+    item_pid INTEGER NOT NULL,
+    data BLOB,
+    PRIMARY KEY (item_pid)
+);
+
+CREATE TABLE IF NOT EXISTS lyrics (
+    item_pid INTEGER NOT NULL,
+    checksum INTEGER,
+    lyrics TEXT,
+    PRIMARY KEY (item_pid)
+);
+"""
+
+
+def write_extras_itdb(
+    path: str,
+    tracks: list[TrackInfo],
+) -> None:
+    """Write Extras.itdb SQLite database.
+
+    Args:
+        path: Output file path.
+        tracks: List of TrackInfo objects.
+    """
+    conn, cur = open_db(path)
+
+    cur.executescript(_EXTRAS_SCHEMA)
+
+    # Insert lyrics for tracks that have them
+    lyrics_count = 0
+    for track in tracks:
+        if track.lyrics:
+            # Simple checksum: sum of bytes mod 2^32
+            checksum = sum(track.lyrics.encode('utf-8')) & 0xFFFFFFFF
+            cur.execute(
+                "INSERT INTO lyrics (item_pid, checksum, lyrics) VALUES (?, ?, ?)",
+                (_s64(track.db_track_id), checksum, track.lyrics)
+            )
+            lyrics_count += 1
+
+    # Insert chapter data for tracks that have chapters
+    chapter_count = 0
+    for track in tracks:
+        cd = track.chapter_data or {}
+        chapters = cd.get("chapters")
+        if chapters:
+            from iTunesDB_Writer.mhod_writer import build_chapter_blob
+            blob = build_chapter_blob(
+                chapters,
+                unk024=cd.get("unk024", 0),
+                unk028=cd.get("unk028", 0),
+                unk032=cd.get("unk032", 0),
+            )
+            if blob:
+                cur.execute(
+                    "INSERT INTO chapter (item_pid, data) VALUES (?, ?)",
+                    (_s64(track.db_track_id), blob)
+                )
+                chapter_count += 1
+
+    conn.commit()
+    conn.close()
+
+    logger.info("Wrote Extras.itdb: %d lyrics entries, %d chapter entries", lyrics_count, chapter_count)

src/vendor/SQLiteDB_Writer/genius_writer.py

@@ -0,0 +1,56 @@
+"""Genius.itdb writer — Genius playlists and similarity data.
+
+Creates a minimal Genius.itdb with empty tables. We don't support Genius
+features, but the database file must exist for the firmware.
+
+Reference: libgpod itdb_sqlite.c mk_Genius()
+"""
+
+import logging
+
+from ._helpers import open_db
+
+logger = logging.getLogger(__name__)
+
+
+_GENIUS_SCHEMA = """
+CREATE TABLE IF NOT EXISTS genius_config (
+    id INTEGER NOT NULL,
+    version INTEGER,
+    default_num_results INTEGER DEFAULT 0,
+    min_num_results INTEGER DEFAULT 0,
+    data BLOB,
+    PRIMARY KEY (id),
+    UNIQUE (version)
+);
+
+CREATE TABLE IF NOT EXISTS genius_metadata (
+    genius_id INTEGER NOT NULL,
+    version INTEGER,
+    data BLOB,
+    PRIMARY KEY (genius_id)
+);
+
+CREATE TABLE IF NOT EXISTS genius_similarities (
+    genius_id INTEGER NOT NULL,
+    version INTEGER,
+    data BLOB,
+    PRIMARY KEY (genius_id)
+);
+"""
+
+
+def write_genius_itdb(path: str) -> None:
+    """Write Genius.itdb SQLite database (empty tables).
+
+    Args:
+        path: Output file path.
+    """
+    conn, cur = open_db(path)
+
+    cur.executescript(_GENIUS_SCHEMA)
+
+    conn.commit()
+    conn.close()
+
+    logger.info("Wrote Genius.itdb (empty)")

src/vendor/SQLiteDB_Writer/locations_writer.py

@@ -0,0 +1,145 @@
+"""Locations.itdb writer — iPod file path mapping database.
+
+Maps track PIDs to their physical file locations on the iPod filesystem.
+
+Schema:
+    base_location: single row with root path "iPod_Control/Music"
+    location: one row per track, mapping item_pid → "Fxx/ABCD.mp3"
+
+Reference: libgpod itdb_sqlite.c mk_Locations()
+"""
+
+import time
+import logging
+
+from iTunesDB_Writer.mhit_writer import TrackInfo
+from iTunesDB_Shared.constants import FILETYPE_CODES
+from ._helpers import s64 as _s64, unix_to_coredata, open_db
+
+logger = logging.getLogger(__name__)
+
+
+# location_type = 0x46494C45 = "FILE" as big-endian int
+LOCATION_TYPE_FILE = 0x46494C45
+
+# Extension codes — same as FILETYPE_CODES (big-endian 4-byte ASCII)
+_EXTENSION_CODES = FILETYPE_CODES
+
+# kind_id mapping — matches location_kind_map in Library.itdb
+# IDs from real iTunes-written databases on Nano 6G
+_KIND_ID = {
+    'mp3': 1,   # "MPEG audio file"
+    'aac': 3,   # "AAC audio file"
+    'm4a': 3,   # "AAC audio file" (or ALAC in M4A container)
+    'm4p': 2,   # "Purchased AAC audio file"
+    'm4b': 3,   # "AAC audio file" (audiobook)
+    'm4v': 3,   #
+    'mp4': 3,   #
+    'wav': 1,   #
+    'aif': 1,   #
+    'aiff': 1,  #
+    'alac': 3,  # ALAC is in M4A container
+}
+
+
+def _ipod_path_to_location(ipod_path: str) -> str:
+    """Convert iPod colon-separated path to slash-based location.
+
+    Input:  ":iPod_Control:Music:F04:ZEUN.mp3"
+    Output: "F04/ZEUN.mp3"
+
+    The location field stores the path relative to the base_location
+    ("iPod_Control/Music"), using forward slashes.
+    """
+    # Strip leading colon and split
+    parts = ipod_path.strip(':').split(':')
+    # Skip "iPod_Control" and "Music" prefix
+    # The path format is :iPod_Control:Music:Fxx:filename
+    # We want: Fxx/filename
+    if len(parts) >= 4 and parts[0] == 'iPod_Control' and parts[1] == 'Music':
+        return '/'.join(parts[2:])
+    elif len(parts) >= 2:
+        # Fallback: just take the last two parts
+        return '/'.join(parts[-2:])
+    else:
+        return ipod_path.strip(':').replace(':', '/')
+
+
+_LOCATIONS_SCHEMA = """
+CREATE TABLE IF NOT EXISTS base_location (
+    id INTEGER NOT NULL,
+    path TEXT,
+    PRIMARY KEY (id)
+);
+
+CREATE TABLE IF NOT EXISTS location (
+    item_pid INTEGER NOT NULL,
+    sub_id INTEGER NOT NULL DEFAULT 0,
+    base_location_id INTEGER DEFAULT 0,
+    location_type INTEGER,
+    location TEXT,
+    extension INTEGER,
+    kind_id INTEGER DEFAULT 0,
+    date_created INTEGER DEFAULT 0,
+    file_size INTEGER DEFAULT 0,
+    file_creator INTEGER,
+    file_type INTEGER,
+    num_dir_levels_file INTEGER,
+    num_dir_levels_lib INTEGER,
+    PRIMARY KEY (item_pid, sub_id)
+);
+"""
+
+
+def write_locations_itdb(
+    path: str,
+    tracks: list[TrackInfo],
+    tz_offset: int = 0,
+) -> None:
+    """Write Locations.itdb SQLite database.
+
+    Args:
+        path: Output file path.
+        tracks: List of TrackInfo objects (with db_track_id and location set).
+        tz_offset: Timezone offset in seconds (positive = east of UTC).
+    """
+    conn, cur = open_db(path)
+
+    cur.executescript(_LOCATIONS_SCHEMA)
+
+    # Single base_location entry
+    cur.execute(
+        "INSERT INTO base_location (id, path) VALUES (1, 'iPod_Control/Music')"
+    )
+
+    # One location per track
+    now = int(time.time())
+
+    for track in tracks:
+        location = _ipod_path_to_location(track.location)
+        ft = track.filetype.lower()
+        extension = _EXTENSION_CODES.get(ft, _EXTENSION_CODES.get('mp3', 0x4D503320))
+        kind_id = _KIND_ID.get(ft, 0)
+
+        # date_created: Core Data timestamp of when the file was added
+        date_added = track.date_added or now
+        date_cd = unix_to_coredata(date_added, tz_offset)
+
+        cur.execute(
+            """INSERT INTO location (
+                item_pid, sub_id, base_location_id, location_type,
+                location, extension, kind_id, date_created, file_size,
+                file_creator, file_type,
+                num_dir_levels_file, num_dir_levels_lib
+            ) VALUES (?, 0, 1, ?, ?, ?, ?, ?, ?, NULL, NULL, NULL, NULL)""",
+            (
+                _s64(track.db_track_id), LOCATION_TYPE_FILE,
+                location, extension, kind_id,
+                date_cd, track.size,
+            )
+        )
+
+    conn.commit()
+    conn.close()
+
+    logger.info("Wrote Locations.itdb: %d locations", len(tracks))

src/vendor/SQLiteDB_Writer/sqlite_writer.py

@@ -0,0 +1,211 @@
+"""SQLite database writer — orchestrates writing all SQLite databases.
+
+This is the main entry point for the SQLiteDB_Writer module. It
+coordinates writing all five databases plus the checksum file for
+iPod Nano 6G/7G.
+
+The databases are written to:
+    /iPod_Control/iTunes/iTunes Library.itlp/
+
+Usage:
+    from SQLiteDB_Writer import write_sqlite_databases
+
+    write_sqlite_databases(
+        ipod_path="/media/ipod",
+        tracks=tracks,
+        playlists=playlists,
+        smart_playlists=smart_playlists,
+        master_playlist_name="iPod",
+    )
+"""
+
+import os
+import random
+import shutil
+import time
+import logging
+import tempfile
+from typing import Optional
+
+from iTunesDB_Writer.mhit_writer import TrackInfo
+from iTunesDB_Writer.mhyp_writer import PlaylistInfo
+from ipod_device import ChecksumType, DeviceCapabilities
+from ipod_device import detect_checksum_type, get_firewire_id
+
+from .library_writer import write_library_itdb
+from .locations_writer import write_locations_itdb
+from .dynamic_writer import write_dynamic_itdb
+from .extras_writer import write_extras_itdb
+from .genius_writer import write_genius_itdb
+from .cbk_writer import write_locations_cbk
+
+logger = logging.getLogger(__name__)
+
+# Directory within iPod where SQLite databases live
+ITLP_DIR = os.path.join("iPod_Control", "iTunes", "iTunes Library.itlp")
+
+
+def write_sqlite_databases(
+    ipod_path: str,
+    tracks: list[TrackInfo],
+    playlists: Optional[list[PlaylistInfo]] = None,
+    smart_playlists: Optional[list[PlaylistInfo]] = None,
+    master_playlist_name: str = "iPod",
+    db_pid: int = 0,
+    capabilities: Optional[DeviceCapabilities] = None,
+    firewire_id: Optional[bytes] = None,
+    backup: bool = True,
+) -> bool:
+    """Write all SQLite databases for iPod Nano 6G/7G.
+
+    Writes the databases to a temp directory first, then atomically
+    replaces the files in the iTunes Library.itlp directory.
+
+    Args:
+        ipod_path: Mount point of iPod (e.g. "E:\\")
+        tracks: List of TrackInfo objects (db_track_id must already be assigned).
+        playlists: User playlists (master is auto-generated).
+        smart_playlists: Smart playlists.
+        master_playlist_name: Name for the master playlist.
+        db_pid: Database persistent ID (from mhbd db_id).
+        capabilities: Device capabilities.
+        firewire_id: 8-byte FireWire GUID for signing.
+        backup: Whether to backup existing databases.
+
+    Returns:
+        True if all databases were written successfully.
+    """
+    itlp_path = os.path.join(ipod_path, ITLP_DIR)
+
+    # Ensure the directory exists
+    os.makedirs(itlp_path, exist_ok=True)
+
+    # Determine timezone offset
+    if time.daylight:
+        tz_offset = -time.altzone
+    else:
+        tz_offset = -time.timezone
+
+    # Determine checksum type
+    checksum_type = ChecksumType.NONE
+    if capabilities:
+        checksum_type = capabilities.checksum
+    else:
+        checksum_type = detect_checksum_type(ipod_path)
+
+    # Get FireWire ID if needed and not provided
+    if firewire_id is None and checksum_type in (
+        ChecksumType.HASHAB, ChecksumType.HASH58
+    ):
+        try:
+            firewire_id = get_firewire_id(ipod_path)
+        except Exception as e:
+            logger.warning("Could not get FireWire ID for cbk signing: %s", e)
+
+    # Generate db_pid if not provided
+    if not db_pid:
+        db_pid = random.getrandbits(64)
+
+    # Backup existing databases
+    if backup:
+        for fname in ("Library.itdb", "Locations.itdb", "Dynamic.itdb",
+                      "Extras.itdb", "Genius.itdb", "Locations.itdb.cbk"):
+            fpath = os.path.join(itlp_path, fname)
+            if os.path.exists(fpath):
+                try:
+                    shutil.copy2(fpath, fpath + ".backup")
+                except Exception as e:
+                    logger.warning("Could not backup %s: %s", fname, e)
+
+    # Write all databases to temp directory first, then move
+    # This gives us atomicity — if any write fails, the originals are intact.
+    with tempfile.TemporaryDirectory(prefix="iOpenPod_sqlite_", ignore_cleanup_errors=True) as tmp_dir:
+        try:
+            # 1. Library.itdb (tracks, albums, artists, playlists, …)
+            lib_path = os.path.join(tmp_dir, "Library.itdb")
+            playlist_pids = write_library_itdb(
+                path=lib_path,
+                tracks=tracks,
+                playlists=playlists,
+                smart_playlists=smart_playlists,
+                master_playlist_name=master_playlist_name,
+                db_pid=db_pid,
+                tz_offset=tz_offset,
+            )
+
+            # 2. Locations.itdb (file path mappings)
+            loc_path = os.path.join(tmp_dir, "Locations.itdb")
+            write_locations_itdb(
+                path=loc_path,
+                tracks=tracks,
+                tz_offset=tz_offset,
+            )
+
+            # 3. Dynamic.itdb (play counts, ratings, bookmarks)
+            dyn_path = os.path.join(tmp_dir, "Dynamic.itdb")
+            write_dynamic_itdb(
+                path=dyn_path,
+                tracks=tracks,
+                playlist_pids=playlist_pids,
+                tz_offset=tz_offset,
+            )
+
+            # 4. Extras.itdb (lyrics, chapters)
+            extras_path = os.path.join(tmp_dir, "Extras.itdb")
+            write_extras_itdb(
+                path=extras_path,
+                tracks=tracks,
+            )
+
+            # 5. Genius.itdb (empty tables)
+            genius_path = os.path.join(tmp_dir, "Genius.itdb")
+            write_genius_itdb(path=genius_path)
+
+            # 6. Locations.itdb.cbk (HASHAB-signed block checksums)
+            cbk_path = os.path.join(tmp_dir, "Locations.itdb.cbk")
+            try:
+                write_locations_cbk(
+                    cbk_path=cbk_path,
+                    locations_itdb_path=loc_path,
+                    checksum_type=checksum_type,
+                    firewire_id=firewire_id,
+                    ipod_path=ipod_path,
+                )
+            except Exception as e:
+                logger.error("Failed to write Locations.itdb.cbk: %s", e)
+                # CBK is critical for signed devices — fail the whole write
+                if checksum_type in (ChecksumType.HASHAB, ChecksumType.HASH72):
+                    raise
+                # For other devices, continue without it
+                cbk_path = None
+
+            # Move all files to the target directory
+            files_to_move = [
+                ("Library.itdb", lib_path),
+                ("Locations.itdb", loc_path),
+                ("Dynamic.itdb", dyn_path),
+                ("Extras.itdb", extras_path),
+                ("Genius.itdb", genius_path),
+            ]
+            if cbk_path and os.path.exists(cbk_path):
+                files_to_move.append(("Locations.itdb.cbk", cbk_path))
+
+            for fname, src_path in files_to_move:
+                dst_path = os.path.join(itlp_path, fname)
+                try:
+                    shutil.copyfile(src_path, dst_path)
+                except Exception as e:
+                    logger.error("Failed to copy %s to iPod: %s", fname, e)
+                    raise
+
+            logger.info("SQLite databases written to %s "
+                        "(%d tracks, %d playlists, %d smart playlists)",
+                        itlp_path, len(tracks),
+                        len(playlists or []),
+                        len(smart_playlists or []))
+            return True
+
+        except Exception as e:
+            logger.error("Failed to write SQLite databases: %s", e,
+                         exc_info=True)
+            return False

src/vendor/iTunesDB_Parser/__init__.py

@@ -0,0 +1,22 @@
+from .exceptions import (
+    CorruptHeaderError,
+    InsufficientDataError,
+    ITunesDBParseError,
+    UnknownChunkTypeError,
+)
+from .parser import decompress_itunescdb, parse_itunesdb
+from .playcounts import PlayCountEntry, merge_playcounts, parse_playcounts
+
+__all__ = [
+    # Public parsing API
+    "parse_itunesdb",
+    "decompress_itunescdb",
+    "parse_playcounts",
+    "merge_playcounts",
+    "PlayCountEntry",
+    # Exceptions
+    "ITunesDBParseError",
+    "CorruptHeaderError",
+    "UnknownChunkTypeError",
+    "InsufficientDataError",
+]

src/vendor/iTunesDB_Parser/_parsing.py

@@ -0,0 +1,69 @@
+"""
+Internal parsing helpers shared across iTunesDB chunk parsers.
+
+Provides:
+- Pre-compiled ``struct.Struct`` objects for common binary field widths.
+- :func:`read_generic_header` — reads the 12-byte generic chunk header.
+
+Child-iteration helpers live in :mod:`chunk_parser` to avoid circular
+imports (they need ``parse_chunk``, which dispatches back to the typed
+parsers that use this module's struct helpers).
+"""
+
+from __future__ import annotations
+
+import struct
+from typing import Any
+
+from .exceptions import CorruptHeaderError, InsufficientDataError
+
+# ── Pre-compiled struct objects ──────────────────────────────────────
+# Used by callers (e.g. mhod_parser) that do inline struct reads.
+# The Shared defs module still uses ad-hoc struct.unpack calls; these
+# are for Parser-local code.
+
+UINT16_LE = struct.Struct("<H")
+UINT32_LE = struct.Struct("<I")
+UINT64_LE = struct.Struct("<Q")
+INT32_LE = struct.Struct("<i")
+FLOAT32_LE = struct.Struct("<f")
+
+# The generic chunk header shared by every iTunesDB chunk:
+#   +0x00  chunk_type  (4 bytes ASCII)
+#   +0x04  header_len  (u32 LE)
+#   +0x08  length_or_child_count  (u32 LE)
+_GENERIC_HEADER = struct.Struct("<4sII")
+GENERIC_HEADER_SIZE = _GENERIC_HEADER.size  # 12 bytes
+
+ParseResult = dict[str, Any]
+"""Return type of every chunk parser: ``{"next_offset": int, "data": ...}``."""
+
+
+def read_generic_header(
+    data: bytes | bytearray,
+    offset: int,
+) -> tuple[str, int, int]:
+    """Read the 12-byte generic chunk header at *offset*.
+
+    Returns:
+        Tuple of ``(chunk_type, header_length, length_or_child_count)``.
+
+    Raises:
+        InsufficientDataError: If fewer than 12 bytes remain at *offset*.
+        CorruptHeaderError: If the chunk type bytes are not valid ASCII.
+    """
+    end = offset + GENERIC_HEADER_SIZE
+    if end > len(data):
+        raise InsufficientDataError(offset, GENERIC_HEADER_SIZE, len(data) - offset)
+
+    raw_type, header_length, length_or_children = _GENERIC_HEADER.unpack_from(data, offset)
+
+    try:
+        chunk_type = raw_type.decode("ascii")
+    except UnicodeDecodeError as exc:
+        raise CorruptHeaderError(
+            offset,
+            f"chunk type bytes are not valid ASCII: {raw_type!r}",
+        ) from exc
+
+    return chunk_type, header_length, length_or_children

src/vendor/iTunesDB_Parser/artwork_links.py

@@ -0,0 +1,88 @@
+"""Helpers for reconciling track artwork links with ArtworkDB.
+
+Older iPod database versions can omit the MHIT ``artwork_id_ref`` field even
+when the track has album art. In those databases the reliable link lives in
+ArtworkDB's MHII ``songId`` field, which equals the track ``db_track_id``.
+"""
+
+from __future__ import annotations
+
+import logging
+from pathlib import Path
+from typing import Any
+
+logger = logging.getLogger(__name__)
+
+
+def _artworkdb_path_from_itunesdb(itunesdb_path: str | Path) -> Path:
+    itunes_path = Path(itunesdb_path)
+    ipod_control = itunes_path.parent.parent
+    return ipod_control / "Artwork" / "ArtworkDB"
+
+
+def _build_song_to_artwork_id(artworkdb_path: Path) -> dict[int, int]:
+    if not artworkdb_path.exists():
+        return {}
+
+    try:
+        from ArtworkDB_Parser.parser import parse_artworkdb
+
+        artworkdb = parse_artworkdb(str(artworkdb_path))
+    except Exception as exc:
+        logger.debug("Could not parse ArtworkDB for artwork links: %s", exc)
+        return {}
+
+    links: dict[int, int] = {}
+    for entry in artworkdb.get("mhli", []):
+        if not isinstance(entry, dict):
+            continue
+        try:
+            song_id = int(entry.get("songId") or entry.get("song_id") or 0)
+            img_id = int(entry.get("img_id") or 0)
+        except (TypeError, ValueError):
+            continue
+        if song_id and img_id:
+            links.setdefault(song_id, img_id)
+    return links
+
+
+def hydrate_track_artwork_refs(
+    tracks: list[dict[str, Any]],
+    itunesdb_path: str | Path,
+) -> int:
+    """Fill missing ``artwork_id_ref`` values from ArtworkDB ``songId`` links.
+
+    Returns the number of tracks updated.
+    """
+    if not tracks:
+        return 0
+
+    song_to_artwork_id = _build_song_to_artwork_id(
+        _artworkdb_path_from_itunesdb(itunesdb_path)
+    )
+    if not song_to_artwork_id:
+        return 0
+
+    hydrated = 0
+    for track in tracks:
+        if not isinstance(track, dict):
+            continue
+        if track.get("artwork_id_ref") not in (None, "", 0):
+            continue
+        try:
+            db_track_id = int(track.get("db_track_id") or track.get("db_id") or 0)
+        except (TypeError, ValueError):
+            continue
+        artwork_id = song_to_artwork_id.get(db_track_id)
+        if not artwork_id:
+            continue
+        track["artwork_id_ref"] = artwork_id
+        if track.get("mhii_link") in (None, "", 0):
+            track["mhii_link"] = artwork_id
+        if not track.get("artwork_count"):
+            track["artwork_count"] = 1
+        hydrated += 1
+
+    if hydrated:
+        logger.info("Hydrated %d track artwork refs from ArtworkDB song links", hydrated)
+    return hydrated

src/vendor/iTunesDB_Parser/chunk_parser.py

@@ -0,0 +1,143 @@
+"""
+Generic chunk dispatcher for iTunesDB chunks.
+
+Every chunk in the iTunesDB starts with the same 12-byte generic header::
+
+    +0x00  chunk_type           (4 bytes ASCII)  e.g. ``mhbd``, ``mhit``
+    +0x04  header_length        (u32 LE)         bytes to end of header
+    +0x08  length_or_children   (u32 LE)         total length *or* child count
+
+This module reads the generic header via :func:`_parsing.read_generic_header`,
+then dispatches to the appropriate ``mh*_parser`` module.
+
+Every parser returns::
+
+    {"next_offset": int, "data": dict | list}
+
+Child-iteration helpers (:func:`parse_children`, :func:`parse_child_list`)
+also live here so that the recursive ``parse_chunk → parser → parse_children
+→ parse_chunk`` loop stays within one module, eliminating the circular import
+that previously existed between ``_parsing`` and ``chunk_parser``.
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import Any
+
+from ._parsing import ParseResult, read_generic_header
+
+logger = logging.getLogger(__name__)
+
+
+# ── Child-iteration helpers ──────────────────────────────────────────
+
+
+def parse_children(
+    data: bytes | bytearray,
+    offset: int,
+    child_count: int,
+) -> tuple[list[dict[str, Any]], int]:
+    """Parse *child_count* consecutive child chunks starting at *offset*.
+
+    Returns:
+        Tuple of ``(children_list, next_offset)`` where each child is
+        ``{"chunk_type": str, "data": <parsed>}``.
+    """
+    children: list[dict[str, Any]] = []
+    current = offset
+    for _ in range(child_count):
+        parsed, chunk_type = parse_chunk(data, current)
+        current = parsed["next_offset"]
+        children.append({"chunk_type": chunk_type, "data": parsed["data"]})
+    return children, current
+
+
+def _parse_child_list(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    child_count: int,
+) -> ParseResult:
+    """Parse a pure-list container (mhlt, mhla, mhli, mhlp).
+
+    These chunks consist solely of a thin header followed by *child_count*
+    sub-chunks with no additional header fields.
+
+    Returns:
+        ``{"next_offset": int, "data": list[...]}``
+    """
+    children, next_offset = parse_children(data, offset + header_length, child_count)
+    return {"next_offset": next_offset, "data": children}
+
+
+# ── Top-level dispatcher ────────────────────────────────────────────
+
+
+def parse_chunk(
+    data: bytes | bytearray,
+    offset: int,
+) -> tuple[dict[str, Any], str]:
+    """Read the generic header at *offset* and delegate to the typed parser.
+
+    Args:
+        data: Full iTunesDB byte buffer.
+        offset: Byte position of the chunk to parse.
+
+    Returns:
+        Tuple of ``(result_dict, chunk_type)`` where *result_dict* contains
+        ``"next_offset"`` and ``"data"`` keys.
+    """
+    chunk_type, header_length, length_or_children = read_generic_header(data, offset)
+
+    match chunk_type:
+        case "mhbd":
+            from .mhbd_parser import parse_db
+            result = parse_db(data, offset, header_length, length_or_children)
+        case "mhsd":
+            from .mhsd_parser import parse_dataset
+            result = parse_dataset(data, offset, header_length, length_or_children)
+
+        # Pure-list containers — no dedicated parser needed.
+        case "mhlt" | "mhla" | "mhli" | "mhlp":
+            result = _parse_child_list(data, offset, header_length, length_or_children)
+
+        case "mhit":
+            from .mhit_parser import parse_track_item
+            result = parse_track_item(data, offset, header_length, length_or_children)
+        case "mhyp":
+            from .mhyp_parser import parse_playlist
+            result = parse_playlist(data, offset, header_length, length_or_children)
+        case "mhip":
+            from .mhip_parser import parse_playlist_item
+            result = parse_playlist_item(data, offset, header_length, length_or_children)
+        case "mhod":
+            from .mhod_parser import parse_mhod
+            result = parse_mhod(data, offset, header_length, length_or_children)
+        case "mhia":
+            from .mhia_parser import parse_album_item
+            result = parse_album_item(data, offset, header_length, length_or_children)
+        case "mhii":
+            # NOTE: shares the 'mhii' magic with ArtworkDB image items,
+            # but in iTunesDB context this is an artist item.
+            from .mhii_parser import parse_artist_item
+            result = parse_artist_item(data, offset, header_length, length_or_children)
+        case _:
+            logger.warning(
+                "Skipping unknown iTunesDB chunk type %r at offset 0x%X",
+                chunk_type, offset,
+            )
+            # NOTE: length_or_children may be a child count rather than
+            # a byte length.  For unknown types we naively treat it as a
+            # length — the worst case is skipping too little, which the
+            # parent's child loop will catch on the next iteration.
+            return {
+                "next_offset": offset + length_or_children,
+                "data": {
+                    "chunk_type": chunk_type,
+                    "header": bytes(data[offset:offset + header_length]),
+                    "body": bytes(data[offset + header_length:offset + length_or_children]),
+                },
+            }, chunk_type
+
+    return result, chunk_type

src/vendor/iTunesDB_Parser/exceptions.py

@@ -0,0 +1,59 @@
+"""
+Custom exception hierarchy for iTunesDB parsing.
+
+All exceptions inherit from :class:`ITunesDBParseError` so callers can catch
+a single base class for any parsing failure.
+"""
+
+
+class ITunesDBParseError(Exception):
+    """Base exception for all iTunesDB parsing failures."""
+
+
+class CorruptHeaderError(ITunesDBParseError):
+    """Raised when a chunk header contains invalid or unrecognizable data.
+
+    Attributes:
+        offset: Byte offset in the data buffer where the header was found.
+        detail: Human-readable description of what went wrong.
+    """
+
+    def __init__(self, offset: int, detail: str) -> None:
+        self.offset = offset
+        self.detail = detail
+        super().__init__(f"Corrupt header at offset 0x{offset:X}: {detail}")
+
+
+class UnknownChunkTypeError(ITunesDBParseError):
+    """Raised when an unrecognized 4-byte chunk identifier is encountered.
+
+    Attributes:
+        offset: Byte offset where the unknown chunk starts.
+        chunk_type: The 4-byte ASCII identifier that was not recognized.
+    """
+
+    def __init__(self, offset: int, chunk_type: str) -> None:
+        self.offset = offset
+        self.chunk_type = chunk_type
+        super().__init__(
+            f"Unknown chunk type {chunk_type!r} at offset 0x{offset:X}"
+        )
+
+
+class InsufficientDataError(ITunesDBParseError):
+    """Raised when the data buffer is too short for the expected read.
+
+    Attributes:
+        offset: Byte offset where the read was attempted.
+        needed: Number of bytes required.
+        available: Number of bytes actually available.
+    """
+
+    def __init__(self, offset: int, needed: int, available: int) -> None:
+        self.offset = offset
+        self.needed = needed
+        self.available = available
+        super().__init__(
+            f"Insufficient data at offset 0x{offset:X}: "
+            f"need {needed} bytes, only {available} available"
+        )

src/vendor/iTunesDB_Parser/ipod_library.py

@@ -0,0 +1,140 @@
+"""
+iPod Library Loader — standalone parser service, no GUI dependency.
+
+Parses iTunesDB + Play Counts, inlines MHOD strings, converts timestamps
+and field values, and returns a flat dict ready for consumption by any
+layer (GUI, CLI, sync engine, tests).
+
+Usage::
+
+    from iTunesDB_Parser.ipod_library import load_ipod_library
+
+    data = load_ipod_library("/Volumes/IPOD/iPod_Control/iTunes/iTunesDB")
+    tracks = data["mhlt"]        # list[dict]
+    albums = data["mhla"]        # list[dict]
+    playlists = data["mhlp"]     # list[dict]
+"""
+
+import logging
+import os
+
+from iTunesDB_Shared.extraction import (
+    extract_datasets,
+    extract_mhod_strings,
+    extract_playlist_extras,
+    extract_track_extras,
+)
+from iTunesDB_Shared.field_base import filetype_to_string
+
+from .parser import parse_itunesdb
+
+logger = logging.getLogger(__name__)
+
+
+def load_ipod_library(itunesdb_path: str,
+                      merge_playcounts: bool = True) -> dict | None:
+    """Parse an iTunesDB file and return normalised data.
+
+    Args:
+        itunesdb_path: Absolute path to the iTunesDB binary file.
+        merge_playcounts: If True (default), also read the sibling
+            ``Play Counts`` file and merge deltas into the track dicts.
+
+    Returns:
+        A dict with keys ``mhlt``, ``mhla``, ``mhlp``, ``mhlp_podcast``,
+        ``mhlp_smart``, ``mhsd_type_8``, etc.  Returns ``None`` when the
+        file does not exist or cannot be parsed.
+    """
+    if not itunesdb_path or not os.path.exists(itunesdb_path):
+        return None
+
+    try:
+        raw = parse_itunesdb(itunesdb_path)
+        data = extract_datasets(raw)
+
+        _inline_track_strings(data)
+        from .artwork_links import hydrate_track_artwork_refs
+
+        hydrate_track_artwork_refs(data.get("mhlt", []), itunesdb_path)
+        _inline_album_strings(data)
+        _inline_playlist_strings(data)
+        _inline_artist_strings(data)
+
+        if merge_playcounts:
+            _merge_play_counts(data, itunesdb_path)
+
+        # Import On-The-Go playlists from OTGPlaylistInfo files.
+        # These are device-created playlists stored outside the iTunesDB.
+        from .otg import load_otg_playlists
+        itunes_dir = os.path.dirname(itunesdb_path)
+        otg = load_otg_playlists(itunes_dir, data.get("mhlt", []))
+        if otg:
+            data.setdefault("mhlp", []).extend(otg)
+
+        return data
+    except Exception:
+        logger.error("Error parsing iTunesDB", exc_info=True)
+        return None
+
+
+# ── Internal helpers ────────────────────────────────────────────────────────
+
+
+def _inline_track_strings(data: dict) -> None:
+    for track in data.get("mhlt", []):
+        children = track.pop("children", [])
+        strings = extract_mhod_strings(children)
+        track.update(strings)
+        track.update(extract_track_extras(children))
+        # filetype u32 → ASCII
+        ft = track.get("filetype")
+        if isinstance(ft, int) and ft > 0:
+            track["filetype"] = filetype_to_string(ft)
+        # sample_rate_1 is already converted from 16.16 fixed-point to Hz
+        # by the read_transform (fixed_to_sample_rate) in mhit_defs.py
+        # sort_mhod_indicators raw bytes → list for JSON serialization
+        raw = track.get("sort_mhod_indicators", b"")
+        if isinstance(raw, (bytes, bytearray)):
+            track["sort_mhod_indicators"] = list(raw)
+
+
+def _inline_album_strings(data: dict) -> None:
+    for album in data.get("mhla", []):
+        strings = extract_mhod_strings(album.pop("children", []))
+        album.update(strings)
+
+
+def _inline_playlist_strings(data: dict) -> None:
+    for key in ("mhlp", "mhlp_podcast", "mhlp_smart"):
+        for pl in data.get(key, []):
+            mhod_children = pl.pop("mhod_children", [])
+            strings = extract_mhod_strings(mhod_children)
+            pl.update(strings)
+            extras = extract_playlist_extras(mhod_children)
+            pl.update(extras)
+            # Flatten MHIP children → items list.
+            # parse_children always returns {"chunk_type": ..., "data": {...}}.
+            items = []
+            for mhip in pl.pop("mhip_children", []):
+                items.append({"track_id": mhip["data"].get("track_id", 0)})
+            pl["items"] = items
+
+
+def _inline_artist_strings(data: dict) -> None:
+    for artist in data.get("mhsd_type_8", []):
+        strings = extract_mhod_strings(artist.pop("children", []))
+        artist.update(strings)
+
+
+def _merge_play_counts(data: dict, itunesdb_path: str) -> None:
+    try:
+        from .playcounts import merge_playcounts as _merge
+        from .playcounts import parse_playcounts
+
+        pc_path = os.path.join(os.path.dirname(itunesdb_path), "Play Counts")
+        entries = parse_playcounts(pc_path)
+        if entries is not None:
+            tracks = data.get("mhlt", [])
+            _merge(tracks, entries)
+    except Exception:
+        logger.debug("Play Counts merge skipped", exc_info=True)

src/vendor/iTunesDB_Parser/mhbd_parser.py

@@ -0,0 +1,39 @@
+"""MHBD (Database Header) parser.
+
+The MHBD chunk is the root of the iTunesDB file.  It contains global
+metadata (version, hashing scheme, persistent IDs, cryptographic hashes)
+followed by one or more MHSD (DataSet) children.
+
+Binary layout (offsets relative to chunk start)::
+
+    +0x00  'mhbd'  magic
+    +0x04  header_length
+    +0x08  total_length (entire file size)
+    +0x0C  compressed flag
+    +0x10  database version
+    +0x14  child_count (number of MHSD datasets)
+    +0x18  db_id (u64)
+    +0x20  platform (u16)  -- 1=Mac, 2=Windows
+    ...    (see mhbd_defs.py for complete field map)
+"""
+
+from __future__ import annotations
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_db(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHBD (Database) chunk and its MHSD children."""
+    mhbd = idb.read_fields(data, offset, "mhbd", header_length)
+    mhbd["children"], _ = parse_children(
+        data, offset + header_length, mhbd["child_count"],
+    )
+    return {"next_offset": offset + chunk_length, "data": mhbd}

src/vendor/iTunesDB_Parser/mhia_parser.py

@@ -0,0 +1,27 @@
+"""MHIA (Album Item) parser.
+
+Each MHIA lives inside an MHLA (album list) and contains album-level
+metadata (album_id, SQL ID, compilation flag) plus MHOD string children
+(types 200-204) with album name, artist, etc.
+"""
+
+from __future__ import annotations
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_album_item(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHIA (Album Item) chunk and its MHOD children."""
+    mhia = idb.read_fields(data, offset, "mhia", header_length)
+    mhia["children"], _ = parse_children(
+        data, offset + header_length, mhia["child_count"],
+    )
+    return {"next_offset": offset + chunk_length, "data": mhia}

src/vendor/iTunesDB_Parser/mhii_parser.py

@@ -0,0 +1,30 @@
+"""MHII (Artist Item) parser for iTunesDB.
+
+Each MHII lives inside an MHLI (artist list, MHSD type 8) and contains
+artist-level metadata (artist_id, SQL ID) plus MHOD type-300 children
+with the artist name string.
+
+NOTE: This chunk shares the ``mhii`` magic with ArtworkDB image items,
+but in the iTunesDB context it represents an artist record.
+"""
+
+from __future__ import annotations  # noqa: I001
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_artist_item(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHII (Artist Item) chunk and its MHOD children."""
+    mhii = idb.read_fields(data, offset, "mhii", header_length)
+    mhii["children"], _ = parse_children(
+        data, offset + header_length, mhii["child_count"],
+    )
+    return {"next_offset": offset + chunk_length, "data": mhii}

src/vendor/iTunesDB_Parser/mhip_parser.py

@@ -0,0 +1,27 @@
+"""MHIP (Playlist Item) parser.
+
+Each MHIP lives inside an MHYP (playlist) and references a track by
+``track_id``.  It may also carry MHOD type-100 children for position
+information.
+"""
+
+from __future__ import annotations
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_playlist_item(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHIP (Playlist Item) chunk and its MHOD children."""
+    mhip = idb.read_fields(data, offset, "mhip", header_length)
+    mhip["children"], _ = parse_children(
+        data, offset + header_length, mhip["child_count"],
+    )
+    return {"next_offset": offset + chunk_length, "data": mhip}

src/vendor/iTunesDB_Parser/mhit_parser.py

@@ -0,0 +1,30 @@
+"""MHIT (Track Item) parser.
+
+Parses a single track record and its MHOD string children.  The MHIT
+header is the largest in the iTunesDB (up to ~500 bytes in newer
+database versions) and contains all numeric track metadata.
+
+The third generic-header field is ``total_length`` (header + body).
+Child count is stored inside the header at offset 0x0C.
+"""
+
+from __future__ import annotations
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_track_item(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHIT (Track Item) chunk and its MHOD children."""
+    mhit = idb.read_fields(data, offset, "mhit", header_length)
+    mhit["children"], _ = parse_children(
+        data, offset + header_length, mhit["child_count"],
+    )
+    return {"next_offset": offset + chunk_length, "data": mhit}

src/vendor/iTunesDB_Parser/mhod_parser.py

@@ -0,0 +1,613 @@
+"""MHOD (Data Object) parser.
+
+MHODs are the most varied chunk type in the iTunesDB.  They are always
+leaf nodes (no sub-chunks) but have a ``type`` field at offset 0x0C that
+determines how the body should be decoded.
+
+Body layouts by type family:
+
+- **String types** (1-14, 18-31, 33-44, 200-204, 300):
+  Standard sub-header at +0x18 with encoding + string_length, then
+  UTF-16LE or UTF-8 string data starting at +0x28.
+
+- **Podcast URL types** (15, 16):
+  UTF-8 string directly after the 24-byte MHOD header (no sub-header).
+
+- **Chapter data** (17):
+  Big-endian atom tree (sean → chap → name) after 12-byte preamble.
+  Contains chapter titles and start positions for audiobooks/podcasts.
+
+- **Binary blob types** (32=video track data):
+  Raw binary stored as hex string for JSON round-tripping.
+
+- **Smart playlist types** (50=SPLPref, 51=SLst rules):
+  Dedicated binary formats.  SLst is the **only** big-endian section
+  in the entire iTunesDB (besides chapter data atoms).
+
+- **Index types** (52=sorted index, 53=jump table):
+  Library playlist indexing data.
+
+- **Playlist settings** (100=position/preferences, 102=binary prefs):
+  Context-dependent layout based on parent chunk (MHIP vs MHYP).
+"""
+
+from __future__ import annotations
+
+import logging
+import struct
+from typing import Any
+
+import iTunesDB_Shared as idb
+
+from ._parsing import UINT16_LE, UINT32_LE, ParseResult
+
+logger = logging.getLogger(__name__)
+
+# ── Local layout constants ─────────────────────────────────────────
+# Binary offsets not already defined in iTunesDB_Shared.mhod_defs.
+# Each is derived from the layout documented in the per-type docstrings.
+
+# MHOD52 (sorted index): sort_type(4) + count(4) + padding(40) = 48
+_MHOD52_INDICES_OFFSET = 48
+
+# MHOD53 (jump table): sort_type(4) + count(4) + padding(8) = 16
+_MHOD53_ENTRIES_OFFSET = 16
+_MHOD53_ENTRY_SIZE = 12  # letter(2) + pad(2) + start(4) + count(4)
+
+# MHOD100: bodies ≤ 20 bytes are MHIP-context (position);
+# larger bodies are MHYP-context (playlist display preferences).
+_MHOD100_MHIP_MAX_BODY = 20
+
+
+# ────────────────────────────────────────────────────────────────────
+# Top-level dispatcher
+# ────────────────────────────────────────────────────────────────────
+
+def parse_mhod(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse a complete MHOD chunk, dispatching by type to the appropriate decoder."""
+    mhod: dict[str, Any] = idb.read_fields(data, offset, "mhod")
+    mhod_type: int = mhod["mhod_type"]
+
+    if mhod_type in idb.mhod_defs.NON_STRING_MHOD_TYPES:
+        body_offset = offset + header_length
+        body_length = chunk_length - header_length
+        mhod["data"] = _parse_nonstring_mhod(data, body_offset, body_length, mhod_type)
+
+    elif mhod_type in idb.mhod_defs.PODCAST_URL_MHOD_TYPES:
+        # Podcast URL types (15, 16): UTF-8/ASCII string directly after
+        # header, with NO sub-header.
+        url_length = chunk_length - header_length
+        if url_length > 0:
+            raw = data[offset + header_length:offset + header_length + url_length]
+            mhod["string"] = raw.decode("utf-8", errors="replace").rstrip("\x00")
+        else:
+            mhod["string"] = ""
+
+    elif mhod_type in idb.mhod_defs.CHAPTER_DATA_MHOD_TYPES:
+        body_offset = offset + header_length
+        body_length = chunk_length - header_length
+        mhod["data"] = _parse_chapter_data(data, body_offset, body_length)
+
+    elif mhod_type in idb.mhod_defs.BINARY_BLOB_MHOD_TYPES:
+        # Binary blob types (32=video track data).
+        blob_length = chunk_length - header_length
+        blob = data[offset + header_length:offset + header_length + blob_length]
+        mhod["string"] = blob.hex()
+
+    elif mhod_type in idb.mhod_defs.STRING_MHOD_TYPES:
+        _parse_string_mhod(data, offset, mhod)
+
+    else:
+        # Unknown MHOD type — return stub.
+        mhod["string"] = ""
+
+    return {"next_offset": offset + chunk_length, "data": mhod}
+
+
+# ────────────────────────────────────────────────────────────────────
+# String MHOD decoder
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_string_mhod(
+    data: bytes | bytearray,
+    offset: int,
+    mhod: dict[str, Any],
+) -> None:
+    """Decode a standard string MHOD (sub-header at +0x18) into *mhod* in-place."""
+    encoding = idb.mhod_defs.mhod_string_encoding(data, offset)
+    string_length = idb.mhod_defs.mhod_string_length(data, offset)
+    mhod["unk_0x20"] = idb.mhod_defs.mhod_string_unk0x20(data, offset)
+    mhod["unk_0x24"] = idb.mhod_defs.mhod_string_unk0x24(data, offset)
+
+    # String data starts after 24-byte header + 16-byte sub-header.
+    string_start = offset + idb.mhod_defs.MHOD_STRING_DATA_OFFSET
+    string_data = data[string_start:string_start + string_length]
+
+    if encoding == 2:
+        mhod["string"] = string_data.decode("utf-8", errors="replace")
+    else:
+        # encoding 0 or 1 = UTF-16LE (most common on iPod).
+        mhod["string"] = string_data.decode("utf-16-le", errors="replace")
+
+
+# ────────────────────────────────────────────────────────────────────
+# Non-string MHOD dispatcher
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_nonstring_mhod(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+    mhod_type: int,
+) -> dict[str, Any]:
+    """Route non-string MHODs to their specific decoders."""
+    match mhod_type:
+        case 50:
+            return _parse_mhod50(data, body_offset, body_length)
+        case 51:
+            return _parse_mhod51(data, body_offset, body_length)
+        case 52:
+            return _parse_mhod52(data, body_offset, body_length)
+        case 53:
+            return _parse_mhod53(data, body_offset, body_length)
+        case 100:
+            return _parse_mhod100(data, body_offset, body_length)
+        case 102:
+            return _parse_mhod102(data, body_offset, body_length)
+        case _:
+            return {}
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 50 — Smart Playlist Preferences (SPLPref)
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_mhod50(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse SPLPref (Smart Playlist Preferences) from MHOD type 50.
+
+    Binary layout (relative to body_offset)::
+
+        +0x00  liveUpdate     (u8)
+        +0x01  checkRules     (u8)
+        +0x02  checkLimits    (u8)
+        +0x03  limitType      (u8)
+        +0x04  limitSort      (u8) + 3 padding bytes
+        +0x08  limitValue     (u32 LE)
+        +0x0C  matchCheckedOnly (u8)  — optional
+        +0x0D  reverseSort    (u8)  — optional
+    """
+    if body_length < 12:
+        logger.warning("MHOD50 (SPLPref) body too short: %d bytes", body_length)
+        return {}
+
+    defs = idb.mhod_defs
+    result: dict[str, Any] = {
+        "live_update": defs.mhod_spl_live_update(data, body_offset),
+        "check_rules": defs.mhod_spl_check_rules(data, body_offset),
+        "check_limits": defs.mhod_spl_check_limits(data, body_offset),
+        "limit_type": defs.mhod_spl_limit_type(data, body_offset),
+        "limit_sort": defs.mhod_spl_limit_sort_raw(data, body_offset),
+        "limit_value": defs.mhod_spl_limit_value(data, body_offset),
+    }
+
+    if body_length >= 13:
+        result["match_checked_only"] = defs.mhod_spl_match_checked_only(data, body_offset)
+    if body_length >= 14:
+        result["reverse_sort"] = defs.mhod_spl_reverse_sort(data, body_offset)
+
+    return result
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 51 — Smart Playlist Rules (SLst)
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_mhod51(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse SPLRules (Smart Playlist Rules) from MHOD type 51.
+
+    CRITICAL: The SLst blob uses BIG-ENDIAN encoding for ALL multi-byte
+    integers — the only part of the iTunesDB that does so.
+    """
+    if body_length < 16:
+        logger.warning("MHOD51 (SPLRules) body too short: %d bytes", body_length)
+        return {}
+
+    slst_magic = idb.mhod_defs.mhod_slst_magic(data, body_offset)
+    if slst_magic != b'SLst':
+        logger.warning("MHOD51: expected SLst magic, got %r", slst_magic)
+        return {}
+
+    defs = idb.mhod_defs
+    rule_count = defs.mhod_slst_rule_count(data, body_offset)
+    result: dict[str, Any] = {
+        "unk004": defs.mhod_slst_unk004(data, body_offset),
+        "rule_count": rule_count,
+        "conjunction": defs.mhod_slst_conjunction(data, body_offset),
+    }
+
+    # Parse individual rules (start after 136-byte SLst header).
+    rules: list[dict[str, Any]] = []
+    rule_offset = body_offset + defs.SLST_HEADER_SIZE
+
+    for _ in range(rule_count):
+        if rule_offset + defs.SPL_RULE_HEADER_SIZE > body_offset + body_length:
+            break
+        rule, rule_total_size = _parse_spl_rule(data, rule_offset)
+        rules.append(rule)
+        rule_offset += rule_total_size
+
+    result["rules"] = rules
+    return result
+
+
+def _parse_spl_rule(
+    data: bytes | bytearray,
+    rule_offset: int,
+) -> tuple[dict[str, Any], int]:
+    """Parse a single SPL rule starting at *rule_offset*.
+
+    All multi-byte integers within SLst rules are BIG-ENDIAN.
+
+    Returns:
+        Tuple of ``(rule_dict, total_rule_size_in_bytes)``.
+    """
+    defs = idb.mhod_defs
+    rule: dict[str, Any] = {}
+
+    field_id = defs.mhod_spl_rule_field(data, rule_offset)
+    rule["field_id"] = field_id
+    rule["action_id"] = defs.mhod_spl_rule_action(data, rule_offset)
+
+    data_length = defs.mhod_spl_rule_data_length(data, rule_offset)
+    rule["data_length"] = data_length
+
+    data_offset = rule_offset + defs.SPL_RULE_HEADER_SIZE
+
+    field_type = defs.spl_get_field_type(field_id)
+
+    if field_type == defs.SPLFT_STRING:
+        # SLst strings are UTF-16 BIG-endian.
+        if data_length > 0:
+            raw = data[data_offset:data_offset + data_length]
+            rule["string_value"] = raw.decode("utf-16-be", errors="replace")
+        else:
+            rule["string_value"] = ""
+    else:
+        # Numeric rule data (INT, DATE, BOOLEAN, PLAYLIST, BINARY_AND).
+        rule["from_value"] = defs.mhod_spl_rule_from_value(data, data_offset)
+        rule["from_date"] = defs.mhod_spl_rule_from_date(data, data_offset)
+        rule["from_units"] = defs.mhod_spl_rule_from_units(data, data_offset)
+        rule["to_value"] = defs.mhod_spl_rule_to_value(data, data_offset)
+        rule["to_date"] = defs.mhod_spl_rule_to_date(data, data_offset)
+        rule["to_units"] = defs.mhod_spl_rule_to_units(data, data_offset)
+        rule["unk052"] = defs.mhod_spl_rule_unk052(data, data_offset)
+        rule["unk056"] = defs.mhod_spl_rule_unk056(data, data_offset)
+        rule["unk060"] = defs.mhod_spl_rule_unk060(data, data_offset)
+        rule["unk064"] = defs.mhod_spl_rule_unk064(data, data_offset)
+        rule["unk068"] = defs.mhod_spl_rule_unk068(data, data_offset)
+
+    total_size = defs.SPL_RULE_HEADER_SIZE + data_length
+    return rule, total_size
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 52 — Library Playlist Index
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_mhod52(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse library playlist sorted index from MHOD type 52.
+
+    Layout::
+
+        +0x00  sort_type  (u32 LE)
+        +0x04  count      (u32 LE)
+        +0x08  padding    (40 bytes)
+        +0x30  indices    (count x u32 LE) — sorted track positions
+    """
+    if body_length < 8:
+        logger.warning("MHOD52 (sorted index) body too short: %d bytes", body_length)
+        return {}
+
+    defs = idb.mhod_defs
+    count = defs.mhod52_count(data, body_offset)
+    result: dict[str, Any] = {
+        "sort_type": defs.mhod52_sort_type(data, body_offset),
+        "count": count,
+    }
+
+    indices_start = body_offset + _MHOD52_INDICES_OFFSET
+    indices: list[int] = []
+    for i in range(count):
+        pos = indices_start + i * 4
+        if pos + 4 <= body_offset + body_length:
+            indices.append(UINT32_LE.unpack_from(data, pos)[0])
+    result["indices"] = indices
+
+    return result
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 53 — Library Playlist Jump Table
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_mhod53(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse library playlist jump table from MHOD type 53.
+
+    Layout::
+
+        +0x00  sort_type  (u32 LE)
+        +0x04  count      (u32 LE)
+        +0x08  padding    (8 bytes)
+        +0x10  entries    (count x 12 bytes each):
+               letter (u16 LE) + pad(2) + start(u32 LE) + count(u32 LE)
+    """
+    if body_length < 8:
+        logger.warning("MHOD53 (jump table) body too short: %d bytes", body_length)
+        return {}
+
+    defs = idb.mhod_defs
+    count = defs.mhod53_count(data, body_offset)
+    result: dict[str, Any] = {
+        "sort_type": defs.mhod53_sort_type(data, body_offset),
+        "count": count,
+    }
+
+    entries_start = body_offset + _MHOD53_ENTRIES_OFFSET
+    entries: list[dict[str, int]] = []
+    for i in range(count):
+        pos = entries_start + i * _MHOD53_ENTRY_SIZE
+        if pos + _MHOD53_ENTRY_SIZE <= body_offset + body_length:
+            letter_code = UINT16_LE.unpack_from(data, pos)[0]
+            start = UINT32_LE.unpack_from(data, pos + 4)[0]
+            entry_count = UINT32_LE.unpack_from(data, pos + 8)[0]
+            entries.append({
+                "letter_code": letter_code,
+                "start": start,
+                "count": entry_count,
+            })
+    result["entries"] = entries
+
+    return result
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 100 — Playlist Position / Preferences
+# ────────────────────────────────────────────────────────────────────
+#
+# Type 100 appears in two contexts:
+# 1. As a child of MHIP: contains track position (small, <=20-byte body)
+# 2. As a child of MHYP: contains playlist display preferences (large, ~624-byte body)
+
+def _parse_mhod100(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse playlist position or preferences from MHOD type 100."""
+    result: dict[str, Any] = {}
+
+    if body_length <= _MHOD100_MHIP_MAX_BODY:
+        # MHIP context: simple position field.
+        if body_length >= 4:
+            result["position"] = idb.mhod_defs.mhod100_position(data, body_offset)
+    else:
+        # MHYP context: playlist display preferences.
+        result["fields"] = _scan_nonzero_fields(data, body_offset, body_length)
+        # Preserve raw bytes for round-trip fidelity.
+        result["raw_body"] = bytes(data[body_offset:body_offset + body_length])
+
+    return result
+
+
+def _scan_nonzero_fields(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, int]:
+    """Scan a binary body for all nonzero bytes, grouped into u32 values.
+
+    Returns a dict mapping hex-offset strings to integer values.
+    Contiguous nonzero bytes within the same 4-byte-aligned u32 are
+    merged into a single LE u32 entry.  Isolated single bytes are
+    returned as-is.
+    """
+    fields: dict[str, int] = {}
+    body = data[body_offset:body_offset + body_length]
+    visited: set[int] = set()
+
+    for i in range(len(body)):
+        if body[i] != 0 and i not in visited:
+            # Try to read as aligned u32 if within bounds.
+            aligned = (i // 4) * 4
+            if aligned + 4 <= len(body):
+                val = UINT32_LE.unpack_from(body, aligned)[0]
+                if val != 0:
+                    fields[f"0x{aligned:03X}"] = val
+                    visited.update(range(aligned, aligned + 4))
+                    continue
+            # Fallback: single byte.
+            fields[f"0x{i:03X}"] = body[i]
+            visited.add(i)
+
+    return fields
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 102 — Playlist Settings (binary, post-iTunes 7)
+# ────────────────────────────────────────────────────────────────────
+
+def _parse_mhod102(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse MHOD type 102 — playlist settings (opaque binary blob)."""
+    return {
+        "fields": _scan_nonzero_fields(data, body_offset, body_length),
+        # Preserve raw bytes for round-trip fidelity.
+        "raw_body": bytes(data[body_offset:body_offset + body_length]),
+    }
+
+
+# ────────────────────────────────────────────────────────────────────
+# MHOD Type 17 — Chapter Data (big-endian atom tree)
+# ────────────────────────────────────────────────────────────────────
+#
+# Chapter data for audiobooks and enhanced podcasts.  The body
+# contains a 12-byte preamble (3 × u32 LE unknown fields) followed by
+# a big-endian atom tree: ``sean`` → ``chap`` × N → ``name`` + ``hedr``.
+#
+# This is the ONLY part of the iTunesDB (besides the SLst smart
+# playlist rules) that uses big-endian encoding for its atoms.
+#
+# Layout (from libgpod itdb_itunesdb.c and iPodLinux wiki):
+#
+#   Preamble (LE):
+#     +0x00  unk024 (u32)
+#     +0x04  unk028 (u32)
+#     +0x08  unk032 (u32)
+#
+#   sean atom (BE):
+#     +0x00  total_size (u32 BE)
+#     +0x04  "sean" (4 bytes)
+#     +0x08  unknown (u32 BE, always 1)
+#     +0x0C  child_count (u32 BE, = num_chapters + 1 for hedr)
+#     +0x10  unknown (u32 BE, always 0)
+#
+#   chap atom (BE), repeated per chapter:
+#     +0x00  total_size (u32 BE)
+#     +0x04  "chap" (4 bytes)
+#     +0x08  startpos (u32 BE, milliseconds)
+#     +0x0C  child_count (u32 BE, = 1 for name)
+#     +0x10  unknown (u32 BE, always 0)
+#     +0x14  name atom...
+#
+#   name atom (BE):
+#     +0x00  total_size (u32 BE)
+#     +0x04  "name" (4 bytes)
+#     +0x08  unknown (u32 BE, always 1)
+#     +0x0C  unknown (u32 BE, always 0)
+#     +0x10  unknown (u32 BE, always 0)
+#     +0x14  string_length (u16 BE, in UTF-16BE code units)
+#     +0x16  title (string_length × 2 bytes, UTF-16BE)
+#
+#   hedr atom (BE, 28 bytes):
+#     +0x00  size=28 (u32 BE)
+#     +0x04  "hedr" (4 bytes)
+#     +0x08  unknown (u32 BE, always 1)
+#     +0x0C  child_count=0 (u32 BE)
+#     +0x10  unknown (u32 BE, always 0)
+#     +0x14  unknown (u32 BE, always 0)
+#     +0x18  unknown (u32 BE, always 1)
+
+_UINT32_BE = struct.Struct(">I")
+_UINT16_BE = struct.Struct(">H")
+
+
+def _parse_chapter_data(
+    data: bytes | bytearray,
+    body_offset: int,
+    body_length: int,
+) -> dict[str, Any]:
+    """Parse chapter data atom tree from MHOD type 17.
+
+    Returns a dict with:
+      - ``unk024``, ``unk028``, ``unk032``: preamble unknowns
+      - ``chapters``: list of {``startpos``: int, ``title``: str}
+    """
+    defs = idb.mhod_defs
+    result: dict[str, Any] = {}
+
+    if body_length < defs.CHAPTER_PREAMBLE_SIZE:
+        logger.warning("MHOD17 (chapter data) too short for preamble: %d bytes", body_length)
+        result["chapters"] = []
+        return result
+
+    # Read 12-byte preamble (little-endian, like the rest of iTunesDB).
+    result["unk024"] = UINT32_LE.unpack_from(data, body_offset)[0]
+    result["unk028"] = UINT32_LE.unpack_from(data, body_offset + 4)[0]
+    result["unk032"] = UINT32_LE.unpack_from(data, body_offset + 8)[0]
+
+    seek = body_offset + defs.CHAPTER_PREAMBLE_SIZE
+    end = body_offset + body_length
+
+    # Check for "sean" atom.
+    if seek + 20 > end:
+        result["chapters"] = []
+        return result
+
+    sean_size = _UINT32_BE.unpack_from(data, seek)[0]
+    if sean_size < 20 or seek + sean_size > end:
+        logger.warning("Chapter data: invalid 'sean' atom size: %d", sean_size)
+        result["chapters"] = []
+        return result
+    sean_magic = data[seek + 4:seek + 8]
+    if sean_magic != defs.SEAN_ATOM:
+        logger.warning("Chapter data: expected 'sean' atom, got %r", sean_magic)
+        result["chapters"] = []
+        return result
+
+    num_children = _UINT32_BE.unpack_from(data, seek + 12)[0]
+    num_chapters = max(0, num_children - 1)  # subtract 1 for hedr
+    seek += 20  # skip sean header
+
+    chapters: list[dict[str, Any]] = []
+    for _ in range(num_chapters):
+        if seek + 20 > end:
+            break
+        chap_magic = data[seek + 4:seek + 8]
+        if chap_magic != defs.CHAP_ATOM:
+            break  # unexpected atom, stop parsing
+
+        chap_size = _UINT32_BE.unpack_from(data, seek)[0]
+        startpos = _UINT32_BE.unpack_from(data, seek + 8)[0]
+        children = _UINT32_BE.unpack_from(data, seek + 12)[0]
+        child_seek = seek + 20
+
+        title = ""
+        for _ in range(children):
+            if child_seek + 22 > end:
+                break
+            child_size = _UINT32_BE.unpack_from(data, child_seek)[0]
+            child_magic = data[child_seek + 4:child_seek + 8]
+            if child_magic == defs.NAME_ATOM:
+                str_len = _UINT16_BE.unpack_from(data, child_seek + 20)[0]
+                str_start = child_seek + 22
+                str_end = str_start + str_len * 2
+                if str_end <= end:
+                    title = data[str_start:str_end].decode("utf-16-be", errors="replace")
+            child_seek += child_size
+
+        chapters.append({"startpos": startpos, "title": title})
+        seek += chap_size
+
+    # Skip hedr atom if present.
+    if seek + 8 <= end:
+        hedr_magic = data[seek + 4:seek + 8]
+        if hedr_magic == defs.HEDR_ATOM:
+            hedr_size = _UINT32_BE.unpack_from(data, seek)[0]
+            seek += hedr_size
+
+    result["chapters"] = chapters
+    return result

src/vendor/iTunesDB_Parser/mhsd_parser.py

@@ -0,0 +1,30 @@
+"""MHSD (DataSet) parser.
+
+An MHSD contains exactly one child chunk whose type is determined by the
+dataset type field at offset 0x0C (see ``constants.chunk_type_map``).
+
+Dataset types: 1=TrackList, 2=PlaylistList, 3=PodcastList, 4=AlbumList,
+5=SmartPlaylistList, 6/10=empty stubs, 8=ArtistList, 9=Genius CUID.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_dataset(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHSD (DataSet) chunk and its single child."""
+    mhsd: dict[str, Any] = idb.read_fields(data, offset, "mhsd", header_length)
+    # MHSD always has exactly one child.
+    mhsd["children"], _ = parse_children(data, offset + header_length, 1)
+    return {"next_offset": offset + chunk_length, "data": mhsd}

src/vendor/iTunesDB_Parser/mhyp_parser.py

@@ -0,0 +1,34 @@
+"""MHYP (Playlist) parser.
+
+An MHYP represents a single playlist.  Its children are split into two
+groups parsed sequentially: MHOD metadata objects first, then MHIP
+playlist-item entries.  The counts are stored separately in the header.
+"""
+
+from __future__ import annotations
+
+import iTunesDB_Shared as idb
+
+from ._parsing import ParseResult
+from .chunk_parser import parse_children
+
+
+def parse_playlist(
+    data: bytes | bytearray,
+    offset: int,
+    header_length: int,
+    chunk_length: int,
+) -> ParseResult:
+    """Parse an MHYP (Playlist) chunk with MHOD + MHIP child groups."""
+    mhyp = idb.read_fields(data, offset, "mhyp", header_length)
+
+    # MHODs come first, then MHIPs — parsed sequentially with shared offset.
+    body_start = offset + header_length
+    mhyp["mhod_children"], mhip_start = parse_children(
+        data, body_start, mhyp["mhod_child_count"],
+    )
+    mhyp["mhip_children"], _ = parse_children(
+        data, mhip_start, mhyp["mhip_child_count"],
+    )
+
+    return {"next_offset": offset + chunk_length, "data": mhyp}

src/vendor/iTunesDB_Parser/otg.py

@@ -0,0 +1,187 @@
+"""On-The-Go (OTG) playlist parser for iPod devices.
+
+The iPod firmware stores device-created playlists in a separate MHPO binary
+file (``OTGPlaylistInfo``) rather than in the iTunesDB.  iTunes and libgpod
+both read these files on connect, import the playlists into the database as
+regular MHYP entries, and then delete the source file.
+
+Reference: libgpod ``process_OTG_file`` / ``read_OTG_playlists`` in ``src/itdb_itunesdb.c``.
+
+MHPO binary layout (little-endian; big-endian devices use magic ``ohpm``):
+
+  +0x00  magic       4 B   "mhpo" (LE) or "ohpm" (BE)
+  +0x04  header_len  u32   size of the header block — always 0x14 (20 B)
+  +0x08  entry_len   u32   size of each track entry — always 0x04 (4 B)
+  +0x0C  entry_num   u32   number of track entries
+  +0x10  (reserved)  4 B   unknown; ignored
+  +0x14  entries     entry_num x entry_len bytes
+           each entry: u32 = 0-based index into the iTunesDB track list (mhlt)
+
+File naming (all in ``iPod_Control/iTunes/``):
+  OTGPlaylistInfo      — first saved OTG playlist
+  OTGPlaylistInfo_1    — second saved OTG playlist
+  OTGPlaylistInfo_2    — third, etc.
+
+The PC sync manager deletes only the base ``OTGPlaylistInfo`` file after
+writing the database.  The iPod firmware removes the numbered variants itself
+once it has processed the updated database.
+(libgpod comment: "the iPod will remove the remaining files".)
+"""
+
+from __future__ import annotations
+
+import hashlib
+import logging
+import os
+import struct
+
+logger = logging.getLogger(__name__)
+
+
+def load_otg_playlists(itunes_dir: str, track_list: list) -> list[dict]:
+    """Parse OTGPlaylistInfo files and return them as regular playlist dicts.
+
+    Each returned dict has the same shape as a playlist produced by
+    ``_inline_playlist_strings`` in ``ipod_library.py``:
+
+      ``Title``       — "On-The-Go 1", "On-The-Go 2", …
+      ``items``       — list of ``{"track_id": <sequential-id>}`` dicts
+      ``playlist_id`` — stable 64-bit ID derived from the file's MD5 so that
+                        repeated rescans without an intervening write don't
+                        introduce duplicates (same file → same ID)
+
+    Args:
+        itunes_dir:  Path to the ``iPod_Control/iTunes`` directory.
+        track_list:  Ordered list of track dicts as returned by the iTunesDB
+                     parser (``data["mhlt"]``).  Entry indices in the MHPO
+                     file are 0-based positions into this list.
+    """
+    paths = _collect_otg_paths(itunes_dir)
+    result: list[dict] = []
+
+    for pl_num, path_str in enumerate(paths, 1):
+        playlist = _parse_one_otg_file(path_str, pl_num, track_list)
+        if playlist is not None:
+            result.append(playlist)
+
+    return result
+
+
+def delete_otg_files(itunes_dir: str) -> None:
+    """Delete the base OTGPlaylistInfo file after a successful database write.
+
+    Matches libgpod's ``itdb_rename_files()`` behaviour: only the base
+    ``OTGPlaylistInfo`` file is removed by the PC sync manager.  The iPod
+    firmware removes the numbered variants (``OTGPlaylistInfo_1``, ``_2``, …)
+    after it processes the new database.
+    """
+    base = os.path.join(itunes_dir, "OTGPlaylistInfo")
+    if not os.path.exists(base):
+        return
+    try:
+        os.unlink(base)
+        logger.info("Deleted OTGPlaylistInfo")
+    except OSError as exc:
+        logger.warning("Could not delete OTGPlaylistInfo: %s", exc)
+
+
+# ── Internal helpers ─────────────────────────────────────────────────────────
+
+
+def _collect_otg_paths(itunes_dir: str) -> list[str]:
+    """Return the ordered list of OTGPlaylistInfo paths that exist.
+
+    Mirrors libgpod's iteration: start with the base file; if it exists,
+    also collect ``_1``, ``_2``, … stopping at the first missing numbered
+    file.  If the base file is absent, return an empty list (libgpod comment:
+    "only parse if OTGPlaylistInfo exists").
+    """
+    base = os.path.join(itunes_dir, "OTGPlaylistInfo")
+    if not os.path.exists(base):
+        return []
+
+    paths = [base]
+    for i in range(1, 20):
+        p = os.path.join(itunes_dir, f"OTGPlaylistInfo_{i}")
+        if not os.path.exists(p):
+            break
+        paths.append(p)
+    return paths
+
+
+def _parse_one_otg_file(
+    path_str: str,
+    pl_num: int,
+    track_list: list,
+) -> dict | None:
+    """Parse a single MHPO file and return a playlist dict, or None on failure."""
+    try:
+        with open(path_str, "rb") as fh:
+            raw = fh.read()
+    except OSError as exc:
+        logger.warning("OTG: could not read %s: %s", path_str, exc)
+        return None
+
+    if len(raw) < 0x14:
+        logger.warning("OTG: %s too short (%d B)", os.path.basename(path_str), len(raw))
+        return None
+
+    magic = raw[0:4]
+    if magic == b"mhpo":
+        fmt = "<I"
+    elif magic == b"ohpm":
+        fmt = ">I"
+    else:
+        logger.warning("OTG: %s has unrecognised magic %r — skipping",
+                       os.path.basename(path_str), magic)
+        return None
+
+    header_len = struct.unpack_from(fmt, raw, 4)[0]
+    entry_len = struct.unpack_from(fmt, raw, 8)[0]
+    entry_num = struct.unpack_from(fmt, raw, 12)[0]
+
+    if header_len < 0x14:
+        logger.warning("OTG: %s header_len %d < 20 — skipping",
+                       os.path.basename(path_str), header_len)
+        return None
+    if entry_len < 4:
+        logger.warning("OTG: %s entry_len %d < 4 — skipping",
+                       os.path.basename(path_str), entry_len)
+        return None
+
+    items: list[dict] = []
+    for i in range(entry_num):
+        offset = header_len + entry_len * i
+        if offset + 4 > len(raw):
+            logger.warning("OTG: %s entry %d extends past EOF — truncating",
+                           os.path.basename(path_str), i)
+            break
+        track_index = struct.unpack_from(fmt, raw, offset)[0]
+        if track_index >= len(track_list):
+            logger.warning(
+                "OTG: %s entry %d references track index %d but track list "
+                "has only %d entries — skipping entry",
+                os.path.basename(path_str), i, track_index, len(track_list),
+            )
+            continue
+        tid = track_list[track_index].get("track_id", 0)
+        if tid:
+            items.append({"track_id": tid})
+
+    # Consistent with libgpod: don't create a playlist for an empty file.
+    if not items:
+        return None
+
+    # Stable playlist_id derived from file content so that re-scanning the
+    # same OTG file before a sync produces the same ID each time, preventing
+    # duplicates in the deduplication step of read_existing_database.
+    playlist_id = int.from_bytes(hashlib.md5(raw).digest()[:8], "little")
+
+    name = f"On-The-Go {pl_num}"
+    logger.info("OTG: imported '%s' (%d tracks) from %s",
+                name, len(items), os.path.basename(path_str))
+    return {
+        "Title": name,
+        "items": items,
+        "playlist_id": playlist_id,
+    }

src/vendor/iTunesDB_Parser/parser.py

@@ -0,0 +1,112 @@
+"""
+iTunesDB / iTunesCDB entry-point parser.
+
+This module provides the public parsing API for Apple's proprietary
+iTunesDB binary database format (and its zlib-compressed variant,
+iTunesCDB).  It accepts either a file path or a file-like object and
+returns a nested dict tree representing the full database hierarchy.
+
+Typical usage::
+
+    from iTunesDB_Parser import parse_itunesdb
+
+    db = parse_itunesdb("/media/ipod/iPod_Control/iTunes/iTunesDB")
+"""
+
+from __future__ import annotations
+
+import logging
+import os
+import zlib
+from typing import Any, BinaryIO
+
+from ._parsing import UINT32_LE
+from .exceptions import CorruptHeaderError
+
+logger = logging.getLogger(__name__)
+
+# Recognized mhbd magic at file offset 0.
+_MHBD_MAGIC = b"mhbd"
+
+# Minimum length to contain the mhbd generic header (magic + header_len + total_len + compressed).
+_MIN_MHBD_HEADER = 16
+
+# iTunesCDB compressed-flag value (mhbd offset 0x0C).
+_COMPRESSED_DB_FLAG = 0x02
+
+
+def decompress_itunescdb(data: bytes | bytearray) -> bytes | bytearray:
+    """Transparently decompress an iTunesCDB into a standard iTunesDB stream.
+
+    If *data* is already an uncompressed iTunesDB (or is too short / has the
+    wrong magic), it is returned as-is.
+
+    Detection logic: the mhbd ``compressed`` field at offset 0x0C is ``2`` for
+    compressed-DB-capable devices, and the payload after the header is a zlib
+    stream.
+
+    Args:
+        data: Raw bytes of an iTunesDB or iTunesCDB file.
+
+    Returns:
+        Decompressed iTunesDB byte stream (original header preserved).
+    """
+    if len(data) < _MIN_MHBD_HEADER or data[:4] != _MHBD_MAGIC:
+        return data
+
+    header_length = UINT32_LE.unpack_from(data, 0x04)[0]
+    compressed_flag = UINT32_LE.unpack_from(data, 0x0C)[0]
+
+    if compressed_flag != _COMPRESSED_DB_FLAG:
+        return data
+
+    try:
+        decompressed = zlib.decompress(data[header_length:])
+    except zlib.error:
+        return data  # not actually compressed — return as-is
+
+    # Reconstruct: original (unmodified) header + decompressed children.
+    # Header's total_length (offset 8) and compression flag are preserved
+    # as-is.  MHBD children are parsed by child_count so the stale
+    # total_length is harmless.
+    logger.debug("iTunesCDB decompressed: %d -> %d payload bytes",
+                 len(data) - header_length, len(decompressed))
+    return data[:header_length] + decompressed
+
+
+def parse_itunesdb(file: str | os.PathLike[str] | BinaryIO) -> dict[str, Any]:
+    """Parse an iTunesDB (or iTunesCDB) file into a nested dict tree.
+
+    Args:
+        file: A filesystem path (``str`` or ``os.PathLike``) or an open
+              binary file-like object positioned at the start of the data.
+
+    Returns:
+        Dict representation of the mhbd root chunk and all children.
+
+    Raises:
+        TypeError: If *file* is not a path or file-like object.
+        ITunesDBParseError: If the binary data cannot be parsed.
+        OSError: If a file path cannot be read.
+    """
+    from .chunk_parser import parse_chunk
+
+    if isinstance(file, (str, os.PathLike)):
+        with open(file, "rb") as fh:
+            data: bytes | bytearray = fh.read()
+    elif hasattr(file, "read"):
+        data = file.read()
+    else:
+        raise TypeError(
+            f"file must be a path (str/PathLike) or a file-like object, "
+            f"got {type(file).__name__}"
+        )
+
+    if not data:
+        raise CorruptHeaderError(0, "empty file")
+
+    # Transparently handle iTunesCDB (compressed database)
+    data = decompress_itunescdb(data)
+
+    parsed, _chunk_type = parse_chunk(data, 0)
+    return parsed["data"]

src/vendor/iTunesDB_Parser/playcounts.py

@@ -0,0 +1,260 @@
+"""
+Play Counts file parser for iPod.
+
+The iPod firmware does NOT modify the iTunesDB directly.  Instead it creates
+a separate binary file at ``/iPod_Control/iTunes/Play Counts`` that records
+per-track deltas (play count, skip count, rating, timestamps) accumulated
+since the last sync.
+
+File layout (iTunes 7+ / entry_length 0x1C):
+
+    Header  (``mhdp``)
+    ┌─────────────┬────────────────────┐
+    │ 0x00  4B    │ magic  "mhdp"      │
+    │ 0x04  4B    │ header_length      │
+    │ 0x08  4B    │ entry_length       │
+    │ 0x0C  4B    │ entry_count        │
+    │ 0x10 …      │ padding → header_length │
+    └─────────────┴────────────────────┘
+
+    Per-entry  (28 bytes for entry_length == 0x1C)
+    ┌─────────────┬────────────────────┐
+    │ 0x00  4B    │ play_count         │
+    │ 0x04  4B    │ last_played (Mac)  │
+    │ 0x08  4B    │ bookmark_time      │
+    │ 0x0C  4B    │ rating (0-100)     │
+    │ 0x10  4B    │ unk16 / podcast    │
+    │ 0x14  4B    │ skip_count         │
+    │ 0x18  4B    │ last_skipped (Mac) │
+    └─────────────┴────────────────────┘
+
+Entries are ordered 1:1 with tracks in the mhlt (matched by index, **not**
+by track ID).  After a sync tool reads this file and folds the deltas into
+the iTunesDB, the file must be **deleted** so the iPod creates a fresh one.
+
+Reference: libgpod ``itdb_itunesdb.c`` → ``playcounts_read()``.
+"""
+
+from __future__ import annotations
+
+import logging
+from dataclasses import dataclass
+from pathlib import Path
+
+from iTunesDB_Shared.field_base import MAC_EPOCH_OFFSET
+
+from ._parsing import UINT32_LE
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass(slots=True)
+class PlayCountEntry:
+    """Delta values for a single track from the Play Counts file."""
+
+    play_count: int = 0
+    last_played_mac: int = 0    # Mac epoch timestamp (0 = not played)
+    bookmark_time: int = 0
+    rating: int = -1            # -1 = no change; 0-100 = new rating
+    skip_count: int = 0
+    last_skipped_mac: int = 0   # Mac epoch timestamp (0 = not skipped)
+
+    # Convenience: is there any delta data in this entry?
+    @property
+    def has_data(self) -> bool:
+        return (
+            self.play_count > 0
+            or self.skip_count > 0
+            or self.rating >= 0
+        )
+
+    @property
+    def last_played_unix(self) -> int:
+        """Last-played as Unix timestamp (0 if never played)."""
+        if self.last_played_mac == 0:
+            return 0
+        return self.last_played_mac - MAC_EPOCH_OFFSET
+
+    @property
+    def last_skipped_unix(self) -> int:
+        """Last-skipped as Unix timestamp (0 if never skipped)."""
+        if self.last_skipped_mac == 0:
+            return 0
+        return self.last_skipped_mac - MAC_EPOCH_OFFSET
+
+
+def parse_playcounts(path: str | Path) -> list[PlayCountEntry] | None:
+    """
+    Parse an iPod Play Counts file.
+
+    Args:
+        path: Path to the ``Play Counts`` file.
+
+    Returns:
+        List of :class:`PlayCountEntry` (one per track, ordered by mhlt
+        index), or ``None`` if the file doesn't exist or can't be parsed.
+    """
+    path = Path(path)
+    if not path.exists():
+        logger.debug("No Play Counts file at %s", path)
+        return None
+
+    try:
+        data = path.read_bytes()
+    except OSError as exc:
+        logger.warning("Could not read Play Counts file: %s", exc)
+        return None
+
+    if len(data) < 16:
+        logger.warning("Play Counts file too small (%d bytes)", len(data))
+        return None
+
+    magic = data[0:4]
+    if magic != b"mhdp":
+        logger.warning("Play Counts file bad magic: %r (expected b'mhdp')", magic)
+        return None
+
+    header_len = UINT32_LE.unpack_from(data, 4)[0]
+    entry_len = UINT32_LE.unpack_from(data, 8)[0]
+    entry_count = UINT32_LE.unpack_from(data, 12)[0]
+
+    expected_size = header_len + entry_len * entry_count
+    if len(data) < expected_size:
+        logger.warning(
+            "Play Counts file truncated: %d bytes < expected %d",
+            len(data), expected_size,
+        )
+        return None
+
+    logger.info(
+        "Play Counts: header=%d, entry_len=%d, entries=%d",
+        header_len, entry_len, entry_count,
+    )
+
+    entries: list[PlayCountEntry] = []
+    for i in range(entry_count):
+        offset = header_len + i * entry_len
+        entry = PlayCountEntry()
+
+        # Minimum fields (always present)
+        entry.play_count = UINT32_LE.unpack_from(data, offset)[0]
+
+        if entry_len >= 8:
+            entry.last_played_mac = UINT32_LE.unpack_from(data, offset + 4)[0]
+
+        if entry_len >= 12:
+            entry.bookmark_time = UINT32_LE.unpack_from(data, offset + 8)[0]
+
+        if entry_len >= 16:
+            raw_rating = UINT32_LE.unpack_from(data, offset + 12)[0]
+            # Convention: rating=0 in the Play Counts file means "no change"
+            # when the track had no user interaction.  The iPod firmware
+            # initialises all entries to zero.  We treat 0 as "unchanged"
+            # to avoid accidentally clearing ratings set on the PC.
+            #
+            # Ratings 20-100 (1-5 stars) are genuine user-set values.
+            # A user *removing* a rating on the iPod is indistinguishable
+            # from "no interaction" — this is a known limitation shared
+            # with libgpod (which checks ``rating != NO_PLAYCOUNT (-1)``
+            # but the firmware never writes -1).
+            if raw_rating > 0:
+                entry.rating = raw_rating
+            # else: stays -1 (no change)
+
+        # entry_len >= 20: unk16 / podcast flag — skipped
+
+        if entry_len >= 24:
+            entry.skip_count = UINT32_LE.unpack_from(data, offset + 20)[0]
+
+        if entry_len >= 28:
+            entry.last_skipped_mac = UINT32_LE.unpack_from(data, offset + 24)[0]
+
+        entries.append(entry)
+
+    active = sum(1 for e in entries if e.has_data)
+    logger.info("Play Counts: %d / %d entries have activity", active, entry_count)
+    return entries
+
+
+def merge_playcounts(
+    tracks: list[dict],
+    entries: list[PlayCountEntry],
+) -> None:
+    """
+    Fold Play Counts deltas into parsed track dicts **in place**.
+
+    After calling this:
+
+    - ``track["play_count_1"]`` is the **new cumulative** play count
+    - ``track["skip_count"]`` is the **new cumulative** skip count
+    - ``track["recent_playcount"]`` is the delta from this session
+    - ``track["recent_skipcount"]`` is the delta from this session
+    - ``track["rating"]`` may be updated if the user rated on the iPod
+    - ``track["last_played"]`` / ``track["last_skipped"]`` may be updated
+
+    This mirrors libgpod's ``get_mhit()`` merge logic.
+    """
+    count = min(len(tracks), len(entries))
+    if len(tracks) != len(entries):
+        logger.warning(
+            "Track count (%d) != Play Counts entry count (%d); "
+            "merging first %d",
+            len(tracks), len(entries), count,
+        )
+
+    merged_plays = 0
+    merged_skips = 0
+    merged_ratings = 0
+
+    for i in range(count):
+        track = tracks[i]
+        entry = entries[i]
+
+        # --- Play count (additive) ---
+        track["recent_playcount"] = entry.play_count
+        track["play_count_1"] = track.get("play_count_1", 0) + entry.play_count
+        if entry.play_count > 0:
+            merged_plays += 1
+
+        # --- Skip count (additive) ---
+        track["recent_skipcount"] = entry.skip_count
+        track["skip_count"] = track.get("skip_count", 0) + entry.skip_count
+        if entry.skip_count > 0:
+            merged_skips += 1
+
+        # --- Rating (override if changed) ---
+        if entry.rating >= 0:  # -1 = no change
+            old_rating = track.get("rating", 0)
+            if old_rating != entry.rating:
+                track["app_rating"] = old_rating  # backup (libgpod convention)
+                track["rating"] = entry.rating
+                merged_ratings += 1
+
+        # --- Bookmark (override — iPod always has the latest position) ---
+        if entry.bookmark_time > 0:
+            track["bookmark_time"] = entry.bookmark_time
+
+        # --- Timestamps (use more-recent value) ---
+        # track["last_played"] is a Unix timestamp (converted from Mac
+        # epoch during iTunesDB parsing).  entry.last_played_mac is raw
+        # Mac epoch.  Use the .last_played_unix property to compare in
+        # the same unit and avoid double-conversion downstream.
+        if entry.last_played_mac > 0:
+            unix_ts = entry.last_played_unix
+            if unix_ts > track.get("last_played", 0):
+                track["last_played"] = unix_ts
+
+        if entry.last_skipped_mac > 0:
+            unix_ts = entry.last_skipped_unix
+            if unix_ts > track.get("last_skipped", 0):
+                track["last_skipped"] = unix_ts
+
+    # Tracks beyond the Play Counts entries get zero deltas
+    for i in range(count, len(tracks)):
+        tracks[i]["recent_playcount"] = 0
+        tracks[i]["recent_skipcount"] = 0
+
+    logger.info(
+        "Merged Play Counts: %d plays, %d skips, %d ratings across %d tracks",
+        merged_plays, merged_skips, merged_ratings, count,
+    )

src/vendor/iTunesDB_Shared/__init__.py

@@ -0,0 +1,32 @@
+from . import field_base as _fb
+from .constants import *  # noqa: F401, F403
+from .extraction import *  # noqa: F401, F403
+from .field_base import *  # noqa: F401, F403
+from .mhbd_defs import *  # noqa: F401, F403
+from .mhbd_defs import MHBD_FIELDS as _mhbd
+from .mhia_defs import *  # noqa: F401, F403
+from .mhia_defs import MHIA_FIELDS as _mhia
+from .mhii_defs import *  # noqa: F401, F403
+from .mhii_defs import MHII_FIELDS as _mhii
+from .mhip_defs import *  # noqa: F401, F403
+from .mhip_defs import MHIP_FIELDS as _mhip
+from .mhit_defs import *  # noqa: F401, F403
+from .mhit_defs import MHIT_FIELDS as _mhit
+from .mhod_defs import *  # noqa: F401, F403
+from .mhod_defs import MHOD_FIELDS as _mhod
+from .mhsd_defs import *  # noqa: F401, F403
+from .mhsd_defs import MHSD_FIELDS as _mhsd
+from .mhyp_defs import *  # noqa: F401, F403
+from .mhyp_defs import MHYP_FIELDS as _mhyp
+
+# ── Build FIELD_REGISTRY from per-chunk defs ────────────────────────
+_fb.FIELD_REGISTRY.update({
+    "mhbd": _mhbd,
+    "mhit": _mhit,
+    "mhsd": _mhsd,
+    "mhia": _mhia,
+    "mhii": _mhii,
+    "mhip": _mhip,
+    "mhyp": _mhyp,
+    "mhod": _mhod,
+})

src/vendor/iTunesDB_Shared/album_identity.py

@@ -0,0 +1,93 @@
+from __future__ import annotations
+
+from collections.abc import Callable, Iterable, Mapping
+from dataclasses import dataclass
+from typing import Generic, TypeVar
+
+T = TypeVar("T")
+
+
+def _clean_text(value: object | None) -> str | None:
+    if value is None:
+        return None
+    text = str(value).strip()
+    return text or None
+
+
+@dataclass(frozen=True)
+class AlbumIdentity:
+    album: str | None
+    album_artist: str | None
+    artist: str | None
+    show_name: str | None
+
+
+def album_identity_from_track(track: object) -> AlbumIdentity:
+    return AlbumIdentity(
+        album=_clean_text(getattr(track, "album", None)),
+        album_artist=_clean_text(getattr(track, "album_artist", None)),
+        artist=_clean_text(getattr(track, "artist", None)),
+        show_name=_clean_text(getattr(track, "show_name", None)),
+    )
+
+
+def album_identity_from_mapping(track: Mapping[str, object]) -> AlbumIdentity:
+    return AlbumIdentity(
+        album=_clean_text(track.get("Album") or track.get("album")),
+        album_artist=_clean_text(
+            track.get("Album Artist") or track.get("album_artist")
+        ),
+        artist=_clean_text(track.get("Artist") or track.get("artist")),
+        show_name=_clean_text(
+            track.get("Show")
+            or track.get("Show Name")
+            or track.get("TV Show")
+            or track.get("show_name")
+        ),
+    )
+
+
+def albums_match(left: AlbumIdentity, right: AlbumIdentity) -> bool:
+    """Match albums using libgpod's album equality rules."""
+    if left.show_name != right.show_name:
+        return False
+    if left.album != right.album:
+        return False
+    if left.album_artist and right.album_artist:
+        return left.album_artist == right.album_artist
+    return left.artist == right.artist
+
+
+@dataclass
+class AlbumGroup(Generic[T]):
+    identity: AlbumIdentity
+    tracks: list[T]
+
+
+def group_tracks_by_album_identity(
+    tracks: Iterable[T],
+    identity_fn: Callable[[T], AlbumIdentity],
+) -> list[AlbumGroup]:
+    """Group tracks into albums using libgpod-compatible matching."""
+    groups: list[AlbumGroup] = []
+    buckets: dict[tuple[str, str], list[int]] = {}
+
+    for track in tracks:
+        identity = identity_fn(track)
+        bucket = (identity.album or "", identity.show_name or "")
+        candidate_idxs = buckets.get(bucket, [])
+
+        match_idx = None
+        for idx in candidate_idxs:
+            if albums_match(identity, groups[idx].identity):
+                match_idx = idx
+                break
+
+        if match_idx is None:
+            match_idx = len(groups)
+            groups.append(AlbumGroup(identity=identity, tracks=[]))
+            buckets.setdefault(bucket, []).append(match_idx)
+
+        groups[match_idx].tracks.append(track)
+
+    return groups

src/vendor/iTunesDB_Shared/constants.py

@@ -0,0 +1,378 @@
+"""
+iTunesDB constants — chunk identifiers, version maps, MHOD type definitions,
+media type bitmask, and playlist sort order values.
+
+Cross-referenced against:
+  - iPodLinux wiki: https://web.archive.org/web/20081006030946/http://ipodlinux.org/wiki/ITunesDB
+  - libgpod itdb_itunesdb.c, itdb.h
+"""
+
+
+# maps the id used in mhsd to the proper header marker
+chunk_type_map = {
+    1: "mhlt",  # Track list (contains MHIT children)
+    2: "mhlp",  # Playlist list (contains MHYP children) — regular playlists
+    3: "mhlp_podcast",  # Podcast list (same MHLP format, different dataset)
+                        # NOTE: Type 3 MHSD MUST come between type 1 and type 2
+                        # for the iPod to list podcasts correctly.
+    4: "mhla",  # Album list (iTunes 7.1+; contains MHIA children)
+    5: "mhlp_smart",  # Smart playlist list (iTunes 7.3+; contains MHYP children)
+    # Types 6–10 were added in iTunes 9+ for Genius and other features.
+    # Their child chunk reuses the 'mhli' magic (same as ArtworkDB's image
+    # list, but here it is a generic item list — different semantics).
+    # We skip their contents but must recognise them to avoid crashing.
+    6: "mhsd_type_6",   # Empty mhlt stub (purpose unknown, written by libgpod/iTunes)
+    7: "mhsd_type_7",   # (reserved, rarely seen)
+    8: "mhsd_type_8",   # Artist list (mhli with mhii children, MHOD type 300)
+    9: "mhsd_type_9",   # Genius Chill list
+    10: "mhsd_type_10",  # Empty mhlt stub (purpose unknown, written by libgpod/iTunes)
+}
+
+# maps the database version to an iTunes version
+version_map = {
+    0x01: "iTunes 1.0",
+    0x02: "iTunes 2.0",
+    0x03: "iTunes 3.0",
+    0x04: "iTunes 4.0",
+    0x05: "iTunes 4.0.1",
+    0x06: "iTunes 4.1",
+    0x07: "iTunes 4.1.1",
+    0x08: "iTunes 4.1.2",
+    0x09: "iTunes 4.2",
+    0x0a: "iTunes 4.5",
+    0x0b: "iTunes 4.7",
+    0x0c: "iTunes 4.71/4.8",
+    0x0d: "iTunes 4.9",
+    0x0e: "iTunes 5",
+    0x0f: "iTunes 6",
+    0x10: "iTunes 6.0.1",
+    0x11: "iTunes 6.0.2-6.0.4",
+    0x12: "iTunes 6.0.5",
+    0x13: "iTunes 7.0",
+    0x14: "iTunes 7.1",
+    0x15: "iTunes 7.2",
+    0x16: "Unknown (0x16)",
+    0x17: "iTunes 7.3.0",
+    0x18: "iTunes 7.3.1-7.3.2",
+    0x19: "iTunes 7.4",
+    0x1a: "iTunes 7.4.1",
+    0x1b: "iTunes 7.4.2",
+    0x1c: "iTunes 7.5",
+    0x1d: "iTunes 7.6",
+    0x1e: "iTunes 7.7",
+    0x1f: "iTunes 8.0",
+    0x20: "iTunes 8.0.1",
+    0x21: "iTunes 8.0.2",
+    0x22: "iTunes 8.1",
+    0x23: "iTunes 8.1.1",
+    0x24: "iTunes 8.2",
+    0x25: "iTunes 8.2.1",
+    0x26: "iTunes 9.0",
+    0x27: "iTunes 9.0.1",
+    0x28: "iTunes 9.0.2",
+    0x29: "iTunes 9.0.3",
+    0x2a: "iTunes 9.1",
+    0x2b: "iTunes 9.1.1",
+    0x2c: "iTunes 9.2",
+    0x2d: "iTunes 9.2.1",
+    0x30: "iTunes 9.2+",
+    # Extended versions for newer databases
+    0x40: "iTunes 10.x",
+    0x50: "iTunes 11.x",
+    0x60: "iTunes 12.x",
+    0x70: "iTunes 12.5+",
+    0x75: "iTunes 12.9+",
+}
+
+
+def get_version_name(version_hex: int | str) -> str:
+    """
+    Get iTunes version name from database version number.
+
+    Args:
+        version_hex: Version as int (0x19) or hex string ('0x19')
+
+    Returns:
+        Human-readable version string
+    """
+    if isinstance(version_hex, str):
+        # Remove '0x' prefix if present and convert
+        version_hex = int(version_hex, 16) if version_hex.startswith('0x') else int(version_hex)
+
+    if version_hex in version_map:
+        return version_map[version_hex]
+
+    # If not exact match, find closest lower version
+    lower_versions = [v for v in version_map if v <= version_hex]
+    if lower_versions:
+        closest = max(lower_versions)
+        return f"{version_map[closest]} (or newer)"
+
+    return f"Unknown (version {hex(version_hex)})"
+
+
+# maps the chunk header marker to a readable name
+# The identifiers read backwards conceptually — the convention is:
+#   mhbd = DataBase Header Marker     mhsd = DataSet Header Marker
+#   mhlt = Track List Header Marker   mhit = Track Item Header Marker
+#   mhlp = Playlist List Header Marker mhla = Album List Header Marker
+#   mhyp = plaYlist Header Marker     mhip = playlist Item Header Marker
+#   mhia = album Item Header Marker   mhod = Data Object Header Marker
+identifier_readable_map = {
+    "mhbd": "Database",
+    "mhsd": "Dataset",
+    "mhlt": "Track List",
+    "mhlp": "Playlist or Podcast List",
+    "mhla": "Album List",
+    "mhli": "Artist List",
+    "mhlp_smart": "Smart Playlist List",
+    "mhia": "Album Item",
+    "mhii": "Artist Item",
+    "mhit": "Track Item",
+    "mhyp": "Playlist",
+    "mhod": "Data Object",
+    "mhip": "Playlist Item",
+}
+
+# maps the mhod type to its readable name
+#
+# Types 1-14:   Track string MHODs (standard sub-header at offset 24)
+# Types 15-16:  Podcast URL MHODs (UTF-8 string at offset 24, NO sub-header)
+# Type 17:      Chapter data (big-endian atom-based binary blob)
+# Types 18-31:  Track string MHODs (standard sub-header)
+# Type 32:      Unknown binary data for video tracks (not a string!)
+# Types 33-44:  Track string MHODs (standard sub-header)
+# Type 50:      Smart playlist preferences (SPLPref binary)
+# Type 51:      Smart playlist rules (SLst — BIG-endian binary)
+# Type 52:      Library playlist sorted index (binary)
+# Type 53:      Library playlist jump table (binary)
+# Type 100:     Playlist column prefs (MHYP child) or position (MHIP child)
+# Type 102:     Playlist settings (post-iTunes 7, binary blob)
+# Types 200-204: Album item string MHODs (standard sub-header)
+mhod_type_map = {
+    1: "Title",
+    2: "Location",
+    3: "Album",
+    4: "Artist",
+    5: "Genre",
+    6: "Filetype",
+    7: "eq_setting",
+    8: "Comment",
+    9: "Category",
+    10: "Lyrics",
+    12: "Composer",
+    13: "Grouping",
+    14: "Description Text",
+    15: "Podcast Enclosure URL",
+    16: "Podcast RSS URL",
+    17: "Chapter Data",
+    18: "Subtitle",
+    19: "Show",
+    20: "Episode",
+    21: "TV Network",
+    22: "Album Artist",
+    23: "Sort Artist",
+    24: "Track Keywords",
+    25: "Show Locale",
+    26: "iTunes Store Asset Info",
+    27: "Sort Title",
+    28: "Sort Album",
+    29: "Sort Album Artist",
+    30: "Sort Composer",
+    31: "Sort Show",
+    32: "Unknown for Video Track",
+    33: "Unknown (33)",
+    34: "Unknown (34)",
+    35: "Unknown (35)",
+    36: "Unknown (36)",
+    37: "Content Provider",
+    38: "Unknown (38)",
+    39: "Copyright",
+    40: "Unknown (40)",
+    41: "Unknown (41)",
+    42: "Encoding Quality Descriptor",
+    43: "Purchase Account",
+    44: "Purchaser Name",
+    50: "Smart Playlist Data",
+    51: "Smart Playlist Rules",
+    52: "Library Playlist Index",
+    53: "Library Playlist Jump Table",
+    100: "Column Size or Playlist Order",
+    102: "Playlist Settings (binary)",
+    200: "Album (Used by Album Item)",
+    201: "Artist (Used by Album Item)",
+    202: "Sort Artist (Used by Album Item)",
+    203: "Podcast URL (Used by Album Item)",
+    204: "Show (Used by Album Item)",
+    # Types 300+: Artist item string MHODs (MHSD type 8)
+    300: "Artist (Used by Artist Item)",
+}
+
+
+# ============================================================
+# Media Type bitmask values (MHIT offset 208 / 0xD0)
+# From libgpod ItdbMediatype enum and iPodLinux wiki.
+# ============================================================
+MEDIA_TYPE_MAP = {
+    0x00000000: "Audio/Video",    # shows in both audio and video menus
+    0x00000001: "Audio",
+    0x00000002: "Video",          # Movie
+    0x00000004: "Podcast",
+    0x00000006: "Video Podcast",
+    0x00000008: "Audiobook",
+    0x00000020: "Music Video",
+    0x00000040: "TV Show",
+    0x00000060: "TV Show (alt)",
+    0x00000100: "Ringtone",        # libgpod ITDB_MEDIATYPE_RINGTONE (1 << 8)
+    0x00000200: "Rental",         # iTunes rental movie
+    0x00004000: "Ringtone (alt)",  # Alternate ringtone value (some firmware)
+    0x00040000: "iTunes Pass",
+    0x00060000: "Memo / Voice Memo",
+}
+
+
+# ============================================================
+# Playlist Sort Order (MHYP offset 44 / 0x2C)
+# From iPodLinux wiki "List Sort Order" and libgpod ItdbPlaylistSortOrder.
+# ============================================================
+PLAYLIST_SORT_ORDER_MAP = {
+    0: "default (unset)",
+    1: "playlist order (manual)",
+    # 2: unknown
+    3: "title",
+    4: "album",
+    5: "artist",
+    6: "bitrate",
+    7: "genre",
+    8: "kind",
+    9: "date modified",
+    10: "track number",
+    11: "size",
+    12: "time",
+    13: "year",
+    14: "sample rate",
+    15: "comment",
+    16: "date added",
+    17: "equalizer",
+    18: "composer",
+    # 19: unknown
+    20: "play count",
+    21: "last played",
+    22: "disc number",
+    23: "my rating",
+    24: "release date",     # used for Podcasts list
+    25: "BPM",
+    26: "grouping",
+    27: "category",
+    28: "description",
+    29: "show",
+    30: "season",
+    31: "episode number",
+}
+
+
+# ============================================================
+# Explicit / content advisory flag values (MHIT offset 146 / 0x92)
+# ============================================================
+EXPLICIT_FLAG_MAP = {
+    0: "none",
+    1: "explicit",
+    2: "clean",
+}
+
+
+# ============================================================
+# MHOD Type Integer Constants
+# Shared by MHOD parser/writer modules.
+# ============================================================
+MHOD_TYPE_TITLE = 1
+MHOD_TYPE_LOCATION = 2
+MHOD_TYPE_ALBUM = 3
+MHOD_TYPE_ARTIST = 4
+MHOD_TYPE_GENRE = 5
+MHOD_TYPE_FILETYPE = 6
+MHOD_TYPE_EQ_SETTING = 7
+MHOD_TYPE_COMMENT = 8
+MHOD_TYPE_CATEGORY = 9
+MHOD_TYPE_LYRICS = 10
+MHOD_TYPE_COMPOSER = 12
+MHOD_TYPE_GROUPING = 13
+MHOD_TYPE_DESCRIPTION = 14
+MHOD_TYPE_PODCAST_ENCLOSURE_URL = 15
+MHOD_TYPE_PODCAST_RSS_URL = 16
+MHOD_TYPE_CHAPTER_DATA = 17
+MHOD_TYPE_SUBTITLE = 18
+MHOD_TYPE_SHOW_NAME = 19
+MHOD_TYPE_EPISODE_ID = 20
+MHOD_TYPE_NETWORK_NAME = 21
+MHOD_TYPE_ALBUM_ARTIST = 22
+MHOD_TYPE_SORT_ARTIST = 23
+MHOD_TYPE_KEYWORDS = 24
+MHOD_TYPE_SHOW_LOCALE = 25
+MHOD_TYPE_SORT_NAME = 27
+MHOD_TYPE_SORT_ALBUM = 28
+MHOD_TYPE_SORT_ALBUM_ARTIST = 29
+MHOD_TYPE_SORT_COMPOSER = 30
+MHOD_TYPE_SORT_SHOW = 31
+MHOD_TYPE_SMART_PLAYLIST_DATA = 50
+MHOD_TYPE_SMART_PLAYLIST_RULES = 51
+MHOD_TYPE_LIBRARY_PLAYLIST_INDEX = 52
+MHOD_TYPE_LIBRARY_PLAYLIST_JUMP_TABLE = 53
+MHOD_TYPE_COLUMN_SIZE_OR_ORDER = 100
+MHOD_TYPE_PLAYLIST_SETTINGS = 102
+# Album item string types
+MHOD_TYPE_ALBUM_ALBUM = 200
+MHOD_TYPE_ALBUM_ARTIST_ITEM = 201
+MHOD_TYPE_ALBUM_SORT_ARTIST = 202
+MHOD_TYPE_ALBUM_PODCAST_URL = 203
+MHOD_TYPE_ALBUM_SHOW = 204
+# Artist item string type
+MHOD_TYPE_ARTIST_NAME = 300
+
+
+# ============================================================
+# File Format Codes (big-endian ASCII stored as LE u32)
+# Shared by track and locations writers.
+# ============================================================
+FILETYPE_CODES: dict[str, int] = {
+    'mp3': 0x4D503320,  # "MP3 "
+    'm4a': 0x4D344120,  # "M4A "
+    'm4p': 0x4D345020,  # "M4P "
+    'm4b': 0x4D344220,  # "M4B "
+    'm4v': 0x4D345620,  # "M4V "
+    'mp4': 0x4D503420,  # "MP4 "
+    'wav': 0x57415620,  # "WAV "
+    'aif': 0x41494646,  # "AIFF"
+    'aiff': 0x41494646,  # "AIFF"
+    'aac': 0x41414320,  # "AAC "
+}
+
+
+# ============================================================
+# Media Type Integer Constants (from libgpod Itdb_Mediatype)
+# Shared by track conversion and writer code.
+# ============================================================
+MEDIA_TYPE_AUDIO = 0x01
+MEDIA_TYPE_VIDEO = 0x02
+MEDIA_TYPE_PODCAST = 0x04
+MEDIA_TYPE_VIDEO_PODCAST = 0x06
+MEDIA_TYPE_AUDIOBOOK = 0x08
+MEDIA_TYPE_MUSIC_VIDEO = 0x20
+MEDIA_TYPE_TV_SHOW = 0x40
+MEDIA_TYPE_RINGTONE = 0x4000
+MEDIA_TYPE_VIDEO_MASK = MEDIA_TYPE_VIDEO | MEDIA_TYPE_MUSIC_VIDEO | MEDIA_TYPE_TV_SHOW
+
+
+# ============================================================
+# Audio Format Flag map (MHIT offset 0x7E)
+# Maps filetype → codec hint value for the audio_format_flag field.
+# 0xFFFF = default (MP3/AAC/ALAC), 0x0000 = lossless (WAV/AIFF),
+# 0x0001 = Audible (M4B audiobooks).
+# ============================================================
+AUDIO_FORMAT_FLAG_MAP: dict[str, int] = {
+    'wav': 0x0000,
+    'aif': 0x0000,
+    'aiff': 0x0000,
+    'm4b': 0x0001,
+}
+AUDIO_FORMAT_FLAG_DEFAULT: int = 0xFFFF

src/vendor/iTunesDB_Shared/extraction.py

@@ -0,0 +1,120 @@
+"""Parser post-processing helpers for flattening parsed iTunesDB dicts.
+
+These functions walk the nested chunk structures produced by the iTunesDB
+parser and extract them into flat, easy-to-consume dictionaries.  They are
+used by ``iTunesDB_Parser.ipod_library`` and ``SyncEngine.sync_executor``.
+"""
+
+from .constants import chunk_type_map, mhod_type_map
+
+
+def extract_datasets(mhbd: dict) -> dict:
+    """Walk the MHBD children and extract datasets into a flat dict.
+
+    Returns a dict with:
+      - All MHBD header fields (excluding 'children')
+      - "mhlt", "mhlp", "mhlp_podcast", "mhla", "mhlp_smart", etc.
+        mapped from MHSD dataset_type via chunk_type_map
+      - Each value is the list of item dicts from the list chunk
+    """
+    result = {}
+    for key, value in mhbd.items():
+        if key != "children":
+            result[key] = value
+
+    for mhsd_wrapper in mhbd.get("children", []):
+        mhsd_data = mhsd_wrapper.get("data", {})
+        dataset_type = mhsd_data.get("dataset_type")
+        result_key = chunk_type_map.get(dataset_type)
+        if result_key is None:
+            continue
+
+        mhsd_children = mhsd_data.get("children", [])
+        if not mhsd_children:
+            result[result_key] = []
+            continue
+
+        # The MHSD has one child: the list chunk (mhlt, mhlp, mhla, mhli)
+        list_chunk = mhsd_children[0]
+        items = list_chunk.get("data", [])
+
+        # Extract items from their wrapper dicts
+        flat_items = []
+        for item in items:
+            if isinstance(item, dict) and "data" in item:
+                flat_items.append(item["data"])
+            else:
+                flat_items.append(item)
+        result[result_key] = flat_items
+
+    return result
+
+
+def extract_mhod_strings(children: list) -> dict:
+    """Extract MHOD string values from a chunk's children list.
+
+    Args:
+        children: The 'children' list from a parsed track/album/artist/playlist.
+
+    Returns:
+        dict mapping mhod_type_map field keys to string values,
+        e.g. {"Title": "My Song", "Artist": "Foo"}
+    """
+    strings = {}
+    for wrapper in children:
+        mhod_data = wrapper.get("data", {})
+        mhod_type = mhod_data.get("mhod_type")
+        if mhod_type is None:
+            continue
+        field_name = mhod_type_map.get(mhod_type)
+        if field_name and "string" in mhod_data:
+            strings[field_name] = mhod_data["string"]
+    return strings
+
+
+def extract_track_extras(mhod_children: list) -> dict:
+    """Extract non-string MHOD data from track children.
+
+    Returns dict with optional keys:
+      - "chapter_data": parsed MHOD type 17 data
+    """
+    extras = {}
+    for wrapper in mhod_children:
+        mhod_data = wrapper.get("data", {})
+        if mhod_data.get("mhod_type") != 17 or "data" not in mhod_data:
+            continue
+
+        raw_chapter_data = mhod_data["data"]
+        if not isinstance(raw_chapter_data, dict):
+            continue
+
+        extras["chapter_data"] = raw_chapter_data
+
+    return extras
+
+
+def extract_playlist_extras(mhod_children: list) -> dict:
+    """Extract non-string MHOD data from playlist children.
+
+    Returns dict with optional keys:
+      - "smart_playlist_data": SPL prefs dict (from MHOD type 50)
+      - "smart_playlist_rules": SPL rules dict (from MHOD type 51)
+      - "library_indices": sorted index data (from MHOD type 52)
+      - "playlist_prefs": column prefs (from MHOD type 100)
+      - "playlist_settings": settings blob (from MHOD type 102)
+    """
+    extras = {}
+    for wrapper in mhod_children:
+        mhod_data = wrapper.get("data", {})
+        mhod_type = mhod_data.get("mhod_type")
+        if mhod_type == 50 and "data" in mhod_data:
+            extras["smart_playlist_data"] = mhod_data["data"]
+        elif mhod_type == 51 and "data" in mhod_data:
+            extras["smart_playlist_rules"] = mhod_data["data"]
+        elif mhod_type == 52 and "data" in mhod_data:
+            extras.setdefault("library_indices", []).append(mhod_data["data"])
+        elif mhod_type == 100 and "data" in mhod_data:
+            extras["playlist_prefs"] = mhod_data["data"]
+        elif mhod_type == 102 and "data" in mhod_data:
+            extras["playlist_settings"] = mhod_data["data"]
+    return extras

src/vendor/iTunesDB_Shared/field_base.py

@@ -0,0 +1,415 @@
+"""Shared infrastructure for bidirectional iTunesDB field definitions.
+
+This module provides the :class:`FieldDef` dataclass, factory helpers,
+transform / validator functions, exception hierarchy, and the read/write
+helpers that all per-chunk ``*_defs.py`` modules build on.
+
+Per-chunk field lists (``MHBD_FIELDS``, ``MHIT_FIELDS``, …) live in their
+own ``*_defs.py`` modules.  The :data:`FIELD_REGISTRY` is assembled at
+import time by :mod:`iTunesDB_Shared.__init__` from those modules.
+"""
+
+from __future__ import annotations
+
+import struct
+from collections.abc import Callable
+from dataclasses import dataclass
+from typing import Any
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  1. Exception Hierarchy
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+
+class WriteError(Exception):
+    """Base exception for iTunesDB write-time errors."""
+
+
+class MissingRequiredFieldError(WriteError):
+    """A field marked ``required=True`` was absent from the values dict."""
+
+    def __init__(self, section_type: str, field_name: str) -> None:
+        super().__init__(
+            f"Required field '{field_name}' missing for section '{section_type}'"
+        )
+        self.section_type = section_type
+        self.field_name = field_name
+
+
+class InvalidFieldValueError(WriteError):
+    """A field validator rejected the value."""
+
+    def __init__(self, section_type: str, field_name: str, detail: str) -> None:
+        super().__init__(
+            f"Invalid value for '{field_name}' in section '{section_type}': {detail}"
+        )
+        self.section_type = section_type
+        self.field_name = field_name
+
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  2. Transform & Validator Functions
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+# Mac HFS+ epoch offset (seconds between 1904-01-01 and 1970-01-01).
+MAC_EPOCH_OFFSET: int = 2082844800
+
+
+def mac_to_unix(mac_ts: int) -> int:
+    """Convert Mac HFS+ timestamp to Unix epoch."""
+    return mac_ts - MAC_EPOCH_OFFSET if mac_ts > 0 else 0
+
+
+def unix_to_mac(unix_ts: int) -> int:
+    """Convert Unix epoch timestamp to Mac HFS+ timestamp."""
+    return unix_ts + MAC_EPOCH_OFFSET if unix_ts > 0 else 0
+
+
+def sample_rate_to_fixed(hz: int) -> int:
+    """Encode sample rate as 16.16 fixed-point for MHIT offset 0x3C."""
+    return (hz << 16) & 0xFFFFFFFF
+
+
+def fixed_to_sample_rate(raw: int) -> int:
+    """Decode 16.16 fixed-point sample rate to integer Hz."""
+    return raw >> 16
+
+
+def validate_rating(value: int) -> None:
+    """Raise if rating is outside 0-100."""
+    if not (0 <= value <= 100):
+        raise ValueError(f"rating {value} outside 0-100")
+
+
+def clamp_rating(value: int) -> int:
+    """Clamp rating to 0-100."""
+    return max(0, min(100, value))
+
+
+def validate_volume(value: int) -> None:
+    """Raise if volume adjustment is outside -255..+255."""
+    if not (-255 <= value <= 255):
+        raise ValueError(f"volume {value} outside -255..+255")
+
+
+def filetype_to_string(val: int) -> str:
+    """Convert a u32 filetype code to its ASCII representation.
+
+    e.g. 0x4D503320 → "MP3", 0x4D344120 → "M4A"
+    """
+    if not isinstance(val, int) or val <= 0:
+        return ""
+    try:
+        return val.to_bytes(4, "big").decode("ascii").rstrip("\x00").strip()
+    except (OverflowError, UnicodeDecodeError):
+        return str(val)
+
+
+def strip_article(name: str) -> str:
+    """Strip leading English articles (A, An, The) for sort field generation.
+
+    iTunes auto-generates sort_title/sort_album/etc. by stripping common
+    English leading articles.  Used by both the binary iTunesDB writer
+    (MHOD type 52 jump tables) and the SQLite writer (sort key columns).
+    """
+    if not name:
+        return name
+    lower = name.lower()
+    for article in ('the ', 'a ', 'an '):
+        if lower.startswith(article):
+            return name[len(article):]
+    return name
+
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  3. FieldDef Dataclass
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+@dataclass(frozen=True, slots=True)
+class FieldDef:
+    """Complete, bidirectional contract for one binary field.
+
+    Attributes:
+        name: Canonical snake_case identifier shared by parser and writer.
+        offset: Byte offset within the section header (relative to chunk start).
+        size: Byte width of the field.
+        struct_format: :mod:`struct` format string (e.g. ``'<I'``, ``'B'``, ``'<8s'``).
+        read_transform: Callable applied AFTER unpacking on parse.
+        write_transform: Callable applied BEFORE packing on write.
+        default: Value used when the field is absent from the data dict.
+        validator: Callable that raises :class:`ValueError` if the value is invalid.
+        min_header_length: Minimum ``header_length`` for this field to exist.
+            ``None`` means the field is always present.
+        required: If ``True``, :func:`write_fields` raises
+            :class:`MissingRequiredFieldError` when the field is absent.
+        section_type: ASCII tag of the parent section (e.g. ``'mhit'``).
+    """
+
+    name: str
+    offset: int
+    size: int
+    struct_format: str
+    read_transform: Callable[..., Any] | None = None
+    write_transform: Callable[..., Any] | None = None
+    default: Any = 0
+    validator: Callable[..., None] | None = None
+    min_header_length: int | None = None
+    required: bool = False
+    section_type: str = ""
+
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  3b. List-container header sizes
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+# Simple list chunks (mhlt, mhla, mhli, mhlp) have only the 12-byte
+# generic header padded to 92 bytes.  They don't carry FieldDef lists.
+
+MHLT_HEADER_SIZE: int = 92
+MHLA_HEADER_SIZE: int = 92
+MHLI_HEADER_SIZE: int = 92
+MHLP_HEADER_SIZE: int = 92
+
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  4. Factory Helpers
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+def _u32(name: str, offset: int, **kw: Any) -> FieldDef:
+    return FieldDef(name=name, offset=offset, size=4, struct_format="<I", **kw)
+
+
+def _i32(name: str, offset: int, **kw: Any) -> FieldDef:
+    return FieldDef(name=name, offset=offset, size=4, struct_format="<i", **kw)
+
+
+def _u16(name: str, offset: int, **kw: Any) -> FieldDef:
+    return FieldDef(name=name, offset=offset, size=2, struct_format="<H", **kw)
+
+
+def _u64(name: str, offset: int, **kw: Any) -> FieldDef:
+    return FieldDef(name=name, offset=offset, size=8, struct_format="<Q", **kw)
+
+
+def _u8(name: str, offset: int, **kw: Any) -> FieldDef:
+    return FieldDef(name=name, offset=offset, size=1, struct_format="B", **kw)
+
+
+def _f32(name: str, offset: int, **kw: Any) -> FieldDef:
+    return FieldDef(name=name, offset=offset, size=4, struct_format="<f", **kw)
+
+
+def _raw(name: str, offset: int, size: int, **kw: Any) -> FieldDef:
+    kw.setdefault("default", b"\x00" * size)
+    return FieldDef(name=name, offset=offset, size=size,
+                    struct_format=f"<{size}s", **kw)
+
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  5. FIELD_REGISTRY & lookup helpers
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+# Populated by __init__.py after all *_defs modules have been imported.
+FIELD_REGISTRY: dict[str, list[FieldDef]] = {}
+
+
+def get_fields(
+    section_type: str,
+    header_length: int | None = None,
+) -> list[FieldDef]:
+    """Return field definitions for *section_type*, optionally filtered.
+
+    Args:
+        section_type: ASCII chunk tag (e.g. ``'mhit'``, ``'mhbd'``).
+        header_length: If provided, fields whose ``min_header_length``
+            exceeds this value are excluded.
+
+    Returns:
+        List of :class:`FieldDef` in offset order.
+    """
+    fields = FIELD_REGISTRY.get(section_type, [])
+    if header_length is not None:
+        return [
+            f for f in fields
+            if f.min_header_length is None or header_length >= f.min_header_length
+        ]
+    return list(fields)
+
+
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+#  6. Read / Write Helpers
+# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+def read_field(
+    data: bytes | bytearray,
+    base_offset: int,
+    field: FieldDef,
+    header_length: int | None = None,
+) -> Any:
+    """Read a single field from *data* at *base_offset*.
+
+    Args:
+        data: Raw byte buffer.
+        base_offset: Start of the chunk in *data*.
+        field: Field definition.
+        header_length: Chunk header length (for version guard).
+
+    Returns:
+        The unpacked (and optionally transformed) value, or
+        ``field.default`` if the header is too small.
+    """
+    if field.min_header_length is not None:
+        if header_length is None or header_length < field.min_header_length:
+            return field.default
+    abs_offset = base_offset + field.offset
+    raw = struct.unpack_from(field.struct_format, data, abs_offset)[0]
+    if field.read_transform is not None:
+        return field.read_transform(raw)
+    return raw
+
+
+def read_fields(
+    data: bytes | bytearray,
+    base_offset: int,
+    section_type: str,
+    header_length: int | None = None,
+) -> dict[str, Any]:
+    """Read all fields for *section_type* into a dict.
+
+    This is the read-side counterpart to :func:`write_fields`.
+
+    Args:
+        data: Raw byte buffer.
+        base_offset: Start of the chunk in *data*.
+        section_type: Chunk tag (e.g. ``'mhit'``).
+        header_length: Actual header length from the chunk.  Extended
+            fields not covered by this length are set to their defaults.
+
+    Returns:
+        Dict mapping field name → value.
+    """
+    result: dict[str, Any] = {}
+    for field in FIELD_REGISTRY.get(section_type, []):
+        result[field.name] = read_field(data, base_offset, field, header_length)
+    return result
+
+
+def write_field(
+    buffer: bytearray,
+    base_offset: int,
+    field: FieldDef,
+    value: Any,
+    section_type: str = "",
+) -> None:
+    """Pack a single field value into *buffer*.
+
+    Applies ``write_transform`` then ``validator`` before packing.
+
+    Args:
+        buffer: Mutable byte buffer to write into.
+        base_offset: Start of the chunk header in *buffer*.
+        field: Field definition.
+        value: The logical value to write.
+        section_type: For error messages only.
+    """
+    if field.write_transform is not None:
+        value = field.write_transform(value)
+    if field.validator is not None:
+        try:
+            field.validator(value)
+        except (ValueError, TypeError) as exc:
+            raise InvalidFieldValueError(
+                section_type or field.section_type, field.name, str(exc),
+            ) from exc
+    # Coerce to the type required by the format code so that floats or other
+    # numeric types from metadata sources never reach struct.pack_into as the
+    # wrong type (e.g. float for an integer field, or int for a float field).
+    format_code = field.struct_format[-1]
+    if format_code in 'IiHhQqBbNnP':
+        if not isinstance(value, int):
+            value = int(value)
+        # Clamp to the valid range for the format so bad metadata (e.g. negative
+        # BPM, oversized play counts) never crashes the packer.
+        int_ranges = {
+            'B': (0, 0xFF),
+            'H': (0, 0xFFFF),
+            'I': (0, 0xFFFF_FFFF),
+            'Q': (0, 0xFFFF_FFFF_FFFF_FFFF),
+            'b': (-0x80, 0x7F),
+            'h': (-0x8000, 0x7FFF),
+            'i': (-0x8000_0000, 0x7FFF_FFFF),
+            'q': (-0x8000_0000_0000_0000, 0x7FFF_FFFF_FFFF_FFFF),
+        }
+        if format_code in int_ranges:
+            lower, upper = int_ranges[format_code]
+            value = max(lower, min(upper, value))
+    elif format_code in 'fd':
+        if not isinstance(value, float):
+            value = float(value)
+    try:
+        struct.pack_into(field.struct_format, buffer, base_offset + field.offset, value)
+    except struct.error as exc:
+        raise struct.error(
+            f"Failed to pack field '{field.name}' (format={field.struct_format!r}, "
+            f"value={value!r} type={type(value).__name__}): {exc}"
+        ) from exc
+
+
+def write_fields(
+    buffer: bytearray,
+    base_offset: int,
+    section_type: str,
+    values: dict[str, Any],
+    header_length: int,
+) -> None:
+    """Write all applicable fields from *values* into *buffer*.
+
+    This is the single serialization entrypoint used by the writer.
+    Fields are written in offset order.  Fields whose
+    ``min_header_length`` exceeds *header_length* are skipped.
+
+    Args:
+        buffer: Pre-allocated mutable buffer (must be ≥ header_length).
+        base_offset: Chunk start position in *buffer*.
+        section_type: Chunk tag (e.g. ``'mhit'``).
+        values: Field name → logical value mapping.
+        header_length: Target header size.  Fields beyond this are skipped.
+
+    Raises:
+        MissingRequiredFieldError: A ``required`` field is missing from *values*.
+        InvalidFieldValueError: A validator rejected a value.
+    """
+    for field in FIELD_REGISTRY.get(section_type, []):
+        # Skip fields outside the target header.
+        if field.min_header_length is not None and header_length < field.min_header_length:
+            continue
+
+        if field.name in values:
+            value = values[field.name]
+        elif field.required:
+            raise MissingRequiredFieldError(section_type, field.name)
+        else:
+            value = field.default
+
+        write_field(buffer, base_offset, field, value, section_type)
+
+
+def write_generic_header(
+    buffer: bytearray,
+    offset: int,
+    tag: bytes,
+    header_length: int,
+    total_length_or_count: int,
+) -> None:
+    """Write the 12-byte generic iTunesDB chunk header.
+
+    Args:
+        buffer: Target buffer.
+        offset: Position in buffer.
+        tag: 4-byte ASCII tag (e.g. ``b'mhit'``).
+        header_length: Header size to write at +0x04.
+        total_length_or_count: Value for +0x08 (total_length for item
+            chunks, child_count for list chunks).
+    """
+    buffer[offset:offset + 4] = tag
+    struct.pack_into("<I", buffer, offset + 4, header_length)
+    struct.pack_into("<I", buffer, offset + 8, total_length_or_count)

src/vendor/iTunesDB_Shared/mhbd_defs.py

@@ -0,0 +1,48 @@
+"""MHBD (Database Header) field definitions.
+
+Declarative :class:`FieldDef` list for the MHBD chunk — the root of
+the iTunesDB file.  Both the parser and writer derive their behaviour
+from these definitions.
+"""
+
+from .field_base import FieldDef, _u32, _i32, _u16, _u64, _raw
+
+_S = "mhbd"
+
+# Writer header size (matching iTunes / libgpod default).
+MHBD_HEADER_SIZE: int = 244  # 0xF4
+
+# Named offsets used by hash modules for zeroing before signing.
+MHBD_OFFSET_DB_ID: int = 0x18           # 8 bytes (u64)
+MHBD_OFFSET_HASHING_SCHEME: int = 0x30  # 2 bytes (u16)
+MHBD_OFFSET_UNK_0x32: int = 0x32        # 20 bytes (raw)
+MHBD_OFFSET_HASH58: int = 0x58          # 20 bytes (raw)
+MHBD_OFFSET_HASH72: int = 0x72          # 46 bytes (raw)
+MHBD_OFFSET_HASHAB: int = 0xAB          # 57 bytes (raw)
+
+MHBD_FIELDS: list[FieldDef] = [
+    _u32("compressed", 0x0C, section_type=_S, default=1),
+    _u32("version", 0x10, section_type=_S, required=True),
+    _u32("child_count", 0x14, section_type=_S),
+    _u64("db_id", 0x18, section_type=_S, required=True),
+    _u16("platform", 0x20, section_type=_S, default=2),
+    _u16("unk0x22", 0x22, section_type=_S, default=0),
+    _u64("db_id_2", 0x24, section_type=_S),
+    _u32("unk0x2c", 0x2C, section_type=_S),
+    _u16("hashing_scheme", 0x30, section_type=_S),
+    _raw("unk0x32", 0x32, 20, section_type=_S),
+    _raw("language", 0x46, 2, section_type=_S, default=b"en"),
+    _u64("db_persistent_id", 0x48, section_type=_S),
+    _u32("unk0x50", 0x50, section_type=_S, default=1),
+    _u32("unk0x54", 0x54, section_type=_S, default=15),
+    _raw("hash58", 0x58, 20, section_type=_S),
+    _i32("timezone_offset", 0x6C, section_type=_S),
+    _u16("hash_type_indicator", 0x70, section_type=_S),
+    _raw("hash72", 0x72, 46, section_type=_S),
+    # Extended fields — only in newer database headers.
+    _u16("audio_language", 0xA0, section_type=_S, min_header_length=0xA2),
+    _u16("subtitle_language", 0xA2, section_type=_S, min_header_length=0xA4),
+    _u16("unk0xa4", 0xA4, section_type=_S, min_header_length=0xA6),
+    _u16("unk0xa6", 0xA6, section_type=_S, min_header_length=0xA8),
+    _u16("cdb_flag", 0xA8, section_type=_S, min_header_length=0xAA),
+]

src/vendor/iTunesDB_Shared/mhia_defs.py

@@ -0,0 +1,21 @@
+"""MHIA (Album Item) field definitions.
+
+Declarative :class:`FieldDef` list for the MHIA chunk — an album
+record inside an MHLA (album list).
+"""
+
+from .field_base import FieldDef, _u32, _u16, _u64
+
+_S = "mhia"
+
+MHIA_HEADER_SIZE: int = 88
+
+MHIA_FIELDS: list[FieldDef] = [
+    _u32("child_count", 0x0C, section_type=_S),
+    _u32("album_id", 0x10, section_type=_S, required=True),
+    _u64("sql_id", 0x14, section_type=_S),
+    _u16("platform_flag", 0x1C, section_type=_S, default=2),
+    _u16("album_compilation_flag", 0x1E, section_type=_S),
+    # Representative track db_track_id — only populated by some iTunes versions
+    _u64("album_track_db_id", 0x20, section_type=_S, min_header_length=0x28),
+]

src/vendor/iTunesDB_Shared/mhii_defs.py

@@ -0,0 +1,18 @@
+"""MHII (Artist Item) field definitions.
+
+Declarative :class:`FieldDef` list for the MHII chunk — an artist
+record inside an MHLI (artist list, MHSD type 8).
+"""
+
+from .field_base import FieldDef, _u32, _u64
+
+_S = "mhii"
+
+MHII_HEADER_SIZE: int = 80
+
+MHII_FIELDS: list[FieldDef] = [
+    _u32("child_count", 0x0C, section_type=_S),
+    _u32("artist_id", 0x10, section_type=_S, required=True),
+    _u64("sql_id", 0x14, section_type=_S),
+    _u32("platform_flag", 0x1C, section_type=_S, default=2),
+]

src/vendor/iTunesDB_Shared/mhip_defs.py

@@ -0,0 +1,26 @@
+"""MHIP (Playlist Item) field definitions.
+
+Declarative :class:`FieldDef` list for the MHIP chunk — a playlist
+entry that references a track by ``track_id``.
+"""
+
+from .field_base import FieldDef, _u32, _u16, _u64, mac_to_unix, unix_to_mac
+
+_S = "mhip"
+
+MHIP_HEADER_SIZE: int = 76
+
+MHIP_FIELDS: list[FieldDef] = [
+    _u32("child_count", 0x0C, section_type=_S),
+    _u16("podcast_group_flag", 0x10, section_type=_S),
+    _u16("unk0x12", 0x12, section_type=_S),
+    _u32("group_id", 0x14, section_type=_S),
+    _u32("track_id", 0x18, section_type=_S, required=True),
+    _u32("timestamp", 0x1C, section_type=_S,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u32("group_id_ref", 0x20, section_type=_S),
+    # Extended (header_length >= 0x34)
+    _u64("track_persistent_id", 0x2C, section_type=_S, min_header_length=0x34),
+    # Extended (header_length >= 0x44) — per-track persistent ID, absent in older iTunes
+    _u64("mhip_persistent_id", 0x3C, section_type=_S, min_header_length=0x44),
+]

src/vendor/iTunesDB_Shared/mhit_defs.py

@@ -0,0 +1,141 @@
+"""MHIT (Track Item) field definitions.
+
+Declarative :class:`FieldDef` list for the MHIT chunk — a single track
+record.  Both the parser and writer derive their behaviour from these
+definitions.
+"""
+
+from .field_base import (
+    FieldDef,
+    _u32, _i32, _u16, _u64, _u8, _f32, _raw,
+    clamp_rating, validate_rating, validate_volume,
+    mac_to_unix, unix_to_mac,
+    fixed_to_sample_rate, sample_rate_to_fixed,
+)
+
+_S = "mhit"
+
+# Writer header size (iTunes 8+ default).
+MHIT_HEADER_SIZE: int = 0x270  # 624 bytes
+
+
+def mhit_header_size_for_version(db_version: int) -> int:
+    """Return the MHIT header size appropriate for *db_version*.
+
+    Older iPod firmware uses smaller MHIT headers.  The writer must pad
+    to the correct boundary so the firmware can locate child MHODs.
+    """
+    if db_version <= 0x12:
+        return 0x9C   # 156 — pre-iTunes 7 minimum
+    if db_version <= 0x19:
+        return 0x148  # 328 — iTunes 7.x
+    if db_version <= 0x2D:
+        return 0x1F8  # 504 — iTunes 9.x
+    return 0x270      # 624 — iTunes 10+ / modern
+
+
+MHIT_FIELDS: list[FieldDef] = [
+    # ── Core fields (always present, minimum header ≥ 0x9C) ──────
+    _u32("child_count", 0x0C, section_type=_S),
+    _u32("track_id", 0x10, section_type=_S, required=True),
+    _u32("visible", 0x14, section_type=_S, default=1),
+    _u32("filetype", 0x18, section_type=_S),
+    _u8("vbr_flag", 0x1C, section_type=_S),
+    _u8("mp3_flag", 0x1D, section_type=_S),
+    _u8("compilation_flag", 0x1E, section_type=_S),
+    _u8("rating", 0x1F, section_type=_S,
+        write_transform=clamp_rating, validator=validate_rating),
+    _u32("last_modified", 0x20, section_type=_S,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u32("size", 0x24, section_type=_S),
+    _u32("length", 0x28, section_type=_S),
+    _u32("track_number", 0x2C, section_type=_S),
+    _u32("total_tracks", 0x30, section_type=_S),
+    _u32("year", 0x34, section_type=_S),
+    _u32("bitrate", 0x38, section_type=_S),
+    _u32("sample_rate_1", 0x3C, section_type=_S,
+         read_transform=fixed_to_sample_rate,
+         write_transform=sample_rate_to_fixed),
+    _i32("volume", 0x40, section_type=_S, validator=validate_volume),
+    _u32("start_time", 0x44, section_type=_S),
+    _u32("stop_time", 0x48, section_type=_S),
+    _u32("sound_check", 0x4C, section_type=_S),
+    _u32("play_count_1", 0x50, section_type=_S),
+    _u32("play_count_2", 0x54, section_type=_S),
+    _u32("last_played", 0x58, section_type=_S,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u32("disc_number", 0x5C, section_type=_S),
+    _u32("total_discs", 0x60, section_type=_S),
+    _u32("user_id", 0x64, section_type=_S),
+    _u32("date_added", 0x68, section_type=_S,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u32("bookmark_time", 0x6C, section_type=_S),
+    _u64("db_track_id", 0x70, section_type=_S, required=True),
+    _u8("checked_flag", 0x78, section_type=_S),
+    _u8("app_rating", 0x79, section_type=_S),
+    _u16("bpm", 0x7A, section_type=_S),
+    _u16("artwork_count", 0x7C, section_type=_S),
+    _u16("audio_format_flag", 0x7E, section_type=_S, default=0xFFFF),
+    _u32("artwork_size", 0x80, section_type=_S),
+    _u32("unk0x84", 0x84, section_type=_S),
+    _f32("sample_rate_2", 0x88, section_type=_S),
+    _u32("date_released", 0x8C, section_type=_S,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u16("mpeg_audio_type", 0x90, section_type=_S),
+    _u8("explicit_flag", 0x92, section_type=_S),
+    _u8("purchased_aac_flag", 0x93, section_type=_S),
+    _u32("unk0x94", 0x94, section_type=_S),
+    _u32("genius_category_id", 0x98, section_type=_S),
+
+    # ── Extended fields (guarded by header_length) ───────────────
+    _u32("skip_count", 0x9C, section_type=_S, min_header_length=0xA0),
+    _u32("last_skipped", 0xA0, section_type=_S, min_header_length=0xA4,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u8("has_artwork", 0xA4, section_type=_S, min_header_length=0xA5),
+    _u8("skip_when_shuffling", 0xA5, section_type=_S, min_header_length=0xA6),
+    _u8("remember_position", 0xA6, section_type=_S, min_header_length=0xA7),
+    _u8("use_podcast_now_playing_flag", 0xA7, section_type=_S, min_header_length=0xA8),
+    _u64("db_track_id_2", 0xA8, section_type=_S, min_header_length=0xB0),
+    _u8("lyrics_flag", 0xB0, section_type=_S, min_header_length=0xB1),
+    _u8("movie_flag", 0xB1, section_type=_S, min_header_length=0xB2),
+    _u8("not_played_flag", 0xB2, section_type=_S, min_header_length=0xB3),
+    _u8("unk0xB3", 0xB3, section_type=_S, min_header_length=0xB4),
+    _u32("unk0xB4", 0xB4, section_type=_S, min_header_length=0xB8),
+    _u32("pregap", 0xB8, section_type=_S, min_header_length=0xBC),
+    _u64("sample_count", 0xBC, section_type=_S, min_header_length=0xC4),
+    _u32("unk0xC4", 0xC4, section_type=_S, min_header_length=0xC8),
+    _u32("postgap", 0xC8, section_type=_S, min_header_length=0xCC),
+    _u32("encoder", 0xCC, section_type=_S, min_header_length=0xD0),
+    _u32("media_type", 0xD0, section_type=_S, min_header_length=0xD4,
+         default=1),
+    _u32("season_number", 0xD4, section_type=_S, min_header_length=0xD8),
+    _u32("episode_number", 0xD8, section_type=_S, min_header_length=0xDC),
+    _u32("date_added_to_itunes", 0xDC, section_type=_S, min_header_length=0xE0,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u32("store_track_id", 0xE0, section_type=_S, min_header_length=0xE4),
+    _u32("store_encoder_version", 0xE4, section_type=_S, min_header_length=0xE8),
+    _u32("store_artist_id", 0xE8, section_type=_S, min_header_length=0xEC),
+    _u32("unk0xEC", 0xEC, section_type=_S, min_header_length=0xF0),
+    _u32("store_album_id", 0xF0, section_type=_S, min_header_length=0xF4),
+    _u32("store_content_flag", 0xF4, section_type=_S, min_header_length=0xF8),
+    _u32("gapless_audio_payload_size", 0xF8, section_type=_S, min_header_length=0xFC),
+    _u32("unk0xFC", 0xFC, section_type=_S, min_header_length=0x100),
+    _u16("gapless_track_flag", 0x100, section_type=_S, min_header_length=0x102),
+    _u16("gapless_album_flag", 0x102, section_type=_S, min_header_length=0x104),
+    _raw("hash_0x104", 0x104, 20, section_type=_S, min_header_length=0x118),
+    _u32("unk0x118", 0x118, section_type=_S, min_header_length=0x11C),
+    _u32("unk0x11C", 0x11C, section_type=_S, min_header_length=0x120),
+    _u32("album_id", 0x120, section_type=_S, min_header_length=0x124),
+    _u64("db_id_2_ref", 0x124, section_type=_S, min_header_length=0x12C),
+    _u32("size_2", 0x12C, section_type=_S, min_header_length=0x130),
+    _u32("unk0x130", 0x130, section_type=_S, min_header_length=0x134),
+    _raw("sort_mhod_indicators", 0x134, 8, section_type=_S, min_header_length=0x13C),
+    # Gap: 0x13C..0x15F (zero padding / unknown fields)
+    _u32("artwork_id_ref", 0x160, section_type=_S, min_header_length=0x164),
+    # 0x168: unknown, libgpod always writes 1
+    _u32("unk0x168", 0x168, section_type=_S, min_header_length=0x16C, default=1),
+    # Gap: 0x16C..0x1DF (zero padding / unknown fields)
+    _u32("artist_id_ref", 0x1E0, section_type=_S, min_header_length=0x1E4),
+    # Gap: 0x1E4..0x1F3 (zero padding / unknown fields)
+    _u32("composer_id", 0x1F4, section_type=_S, min_header_length=0x1F8),
+]

src/vendor/iTunesDB_Shared/mhod_defs.py

@@ -0,0 +1,586 @@
+"""MHOD (Data Object) field definitions and helpers.
+
+Contains the :class:`FieldDef` list for the 24-byte common MHOD header,
+plus type classification sets, string sub-header accessors, and
+SPL / SLst / MHOD-52 / MHOD-53 / MHOD-100 / MHOD-102 parsing helpers.
+
+The body-level layouts vary widely by MHOD type and do NOT fit the
+simple ``FieldDef`` pattern, so they remain as hand-written helpers here.
+"""
+
+import struct
+
+from .field_base import FieldDef, _u32
+
+_S = "mhod"
+
+MHOD_HEADER_SIZE: int = 24  # common header (body varies by type)
+
+# ── String MHOD sub-header layout ──────────────────────────
+MHOD_STRING_SUBHEADER_OFFSET = 0x18   # sub-header start (relative to chunk start)
+MHOD_STRING_SUBHEADER_SIZE = 16       # encoding(4) + length(4) + unk0x20(4) + unk0x24(4)
+MHOD_STRING_DATA_OFFSET = 0x28        # string data start (header + sub-header)
+
+# ── SPLPref body (MHOD type 50) ───────────────────────────
+SPLPREF_BODY_SIZE = 132
+
+# ── SLst rule data (MHOD type 51) non-string body size ────
+SPL_RULE_DATA_SIZE = 0x44  # 68 bytes
+
+# ── MHOD type 52/53 body layout sizes ─────────────────────
+MHOD52_BODY_HEADER_SIZE = 48  # sort_type(4) + count(4) + padding(40)
+MHOD53_BODY_HEADER_SIZE = 16  # sort_type(4) + count(4) + padding(8)
+MHOD53_ENTRY_SIZE = 12        # letter(2) + pad(2) + start(4) + count(4)
+
+# ── MHOD type 100 body layout ─────────────────────────────
+MHOD100_POSITION_BODY_SIZE = 20  # position(4) + padding(16)
+
+# ── MHOD 52/53 sort type constants (from libgpod MHOD52_SORTTYPE) ──
+SORT_TITLE = 0x03
+SORT_ALBUM = 0x04
+SORT_ARTIST = 0x05
+SORT_GENRE = 0x07
+SORT_COMPOSER = 0x12
+SORT_SHOW = 0x1D
+SORT_SEASON = 0x1E
+SORT_EPISODE = 0x1F
+SORT_ALBUM_ARTIST = 0x23
+
+# ── Chapter Data atom constants (MHOD type 17, all big-endian) ──
+# The chapter data body starts with 12 bytes of unknown data
+# (unk024, unk028, unk032 per libgpod), followed by a "sean" atom tree.
+CHAPTER_PREAMBLE_SIZE = 12  # 3 × u32 LE before the atom tree
+SEAN_ATOM = b'sean'
+CHAP_ATOM = b'chap'
+NAME_ATOM = b'name'
+HEDR_ATOM = b'hedr'
+HEDR_SIZE = 28  # hedr atom is always 28 bytes
+
+MHOD_FIELDS: list[FieldDef] = [
+    _u32("mhod_type", 0x0C, section_type=_S, required=True),
+    _u32("unk0x10", 0x10, section_type=_S),
+    _u32("unk0x14", 0x14, section_type=_S),
+]
+
+
+# ============================================================
+# Type Classification Sets
+# ============================================================
+
+# String MHOD types that use the standard sub-header at offset 0x18.
+# Types 1-14, 18-31, 33-44 are track/item string metadata.
+# Types 200-204 are album item strings.
+#
+# EXCLUDED from this set (handled separately):
+#   15-16: Podcast URLs — UTF-8 string with NO sub-header
+#   17:    Chapter data — big-endian atom blob
+#   32:    Video track data — binary, not a string
+STRING_MHOD_TYPES = (
+    set(range(1, 15))      # 1..14
+    | set(range(18, 32))   # 18..31
+    | set(range(33, 45))   # 33..44
+    | set(range(200, 205))  # 200..204
+    | {300}                # artist item name (MHSD type 8)
+)
+
+# Podcast URL types — UTF-8/ASCII string directly at body start, no sub-header.
+PODCAST_URL_MHOD_TYPES = {15, 16}
+
+# Chapter data MHOD type — big-endian atom tree (sean/chap/name/hedr).
+CHAPTER_DATA_MHOD_TYPES = {17}
+
+# Binary / opaque MHOD types — stored as raw hex for round-tripping.
+BINARY_BLOB_MHOD_TYPES = {32}
+
+# Non-string MHOD types with dedicated binary formats.
+NON_STRING_MHOD_TYPES = {50, 51, 52, 53, 100, 102}
+
+
+# ============================================================
+# Common MHOD Header (24 bytes — always 0x18)
+# ============================================================
+# The 3 common header fields (type, unk0x10, unk0x14) are defined in
+# MHOD_FIELDS above and read via read_fields().  The per-type body
+# helpers below still use struct directly since they don't fit FieldDef.
+
+
+def write_mhod_header(mhod_type: int, total_length: int,
+                      unk0x10: int = 0, unk0x14: int = 0) -> bytes:
+    """Build the 24-byte MHOD common header.
+
+    This is the shared pattern used by every MHOD writer — string,
+    SPL, index, position, etc.
+
+    Args:
+        mhod_type: MHOD type ID (e.g. 1, 50, 51, 52, 53, 100, 102).
+        total_length: Total length of the complete MHOD chunk
+            (header + body).
+        unk0x10: Unknown field at offset 0x10 (preserved from parser).
+        unk0x14: Unknown field at offset 0x14 (preserved from parser).
+
+    Returns:
+        24-byte packed header.
+    """
+    return struct.pack(
+        '<4sIIIII',
+        b'mhod',
+        MHOD_HEADER_SIZE,
+        total_length,
+        mhod_type,
+        unk0x10,
+        unk0x14,
+    )
+
+
+# ============================================================
+# String MHOD Sub-Header (starts at 0x18, 16 bytes)
+# ============================================================
+# Present on STRING_MHOD_TYPES only. NOT present on podcast URLs (15/16).
+# All functions take offset = start of the MHOD chunk.
+#
+#   +0x18: encoding (4 bytes) — 1=UTF-16LE, 2=UTF-8
+#   +0x1C: string_length (4 bytes) — byte count of string data
+#   +0x20: unk0x20 (4 bytes)
+#   +0x24: unk0x24 (4 bytes)
+#   +0x28: string data begins (string_length bytes)
+
+def mhod_string_encoding(data, offset) -> int:
+    """Position/encoding indicator at 0x18.
+    1 (or 0) = UTF-16LE (standard iPod, little-endian strings).
+    2 = UTF-8 (mobile-phone iTunesDBs, inversed endian).
+    libgpod checks this same field to decide encoding."""
+    return struct.unpack("<I", data[offset + 0x18:offset + 0x1C])[0]
+
+
+def mhod_string_length(data, offset) -> int:
+    """Byte length of string data at 0x1C."""
+    return struct.unpack("<I", data[offset + 0x1C:offset + 0x20])[0]
+
+
+def mhod_string_unk0x20(data, offset) -> int:
+    return struct.unpack("<I", data[offset + 0x20:offset + 0x24])[0]
+
+
+def mhod_string_unk0x24(data, offset) -> int:
+    return struct.unpack("<I", data[offset + 0x24:offset + 0x28])[0]
+
+
+# ============================================================
+# SPLPref — Smart Playlist Preferences (MHOD type 50)
+# ============================================================
+# All functions take body_offset = start of SPLPref data (MHOD chunk + header_length).
+#
+# Based on libgpod's SPLPref struct (itdb_spl.c) and the iPodLinux wiki.
+#
+#   +0x00: liveUpdate (1 byte) — 1 = auto-update when library changes
+#   +0x01: checkRules (1 byte) — 1 = limit by rules (match checked items)
+#   +0x02: checkLimits (1 byte) — 1 = limit by size/count/time
+#   +0x03: limitType (1 byte) — what the limit applies to (see SPL_LIMIT_TYPE_MAP)
+#   +0x04: limitSort (1 byte) — how to choose items when limited (see SPL_LIMIT_SORT_MAP)
+#   +0x05: pad (3 bytes)
+#   +0x08: limitValue (4 bytes LE) — the limit value
+#   +0x0C: matchCheckedOnly (1 byte) — 1 = only match checked items
+#   +0x0D: reverseSort (1 byte) — if set, limitsort |= 0x80000000
+
+def mhod_spl_live_update(data, body_offset) -> int:
+    return data[body_offset]
+
+
+def mhod_spl_check_rules(data, body_offset) -> int:
+    return data[body_offset + 1]
+
+
+def mhod_spl_check_limits(data, body_offset) -> int:
+    return data[body_offset + 2]
+
+
+def mhod_spl_limit_type(data, body_offset) -> int:
+    return data[body_offset + 3]
+
+
+def mhod_spl_limit_sort_raw(data, body_offset) -> int:
+    """Raw limit sort byte at +0x04 (before reverse flag is applied)."""
+    return data[body_offset + 4]
+
+
+def mhod_spl_limit_value(data, body_offset) -> int:
+    return struct.unpack("<I", data[body_offset + 8:body_offset + 12])[0]
+
+
+def mhod_spl_match_checked_only(data, body_offset) -> int:
+    return data[body_offset + 12]
+
+
+def mhod_spl_reverse_sort(data, body_offset) -> int:
+    """Reverse flag at +0x0D. If set, limitsort |= 0x80000000."""
+    return data[body_offset + 13]
+
+
+# Limit type names (from libgpod ItdbLimitType)
+SPL_LIMIT_TYPE_MAP = {
+    0x01: "minutes",
+    0x02: "MB",
+    0x03: "songs",
+    0x04: "hours",
+    0x05: "GB",
+}
+
+# Limit sort names (from libgpod ItdbLimitSort).
+# The 0x80000000 bit is the "reverse" flag, stored separately at SPLPref +13.
+SPL_LIMIT_SORT_MAP = {
+    0x02: "random",
+    0x03: "song_name",
+    0x04: "album",
+    0x05: "artist",
+    0x07: "genre",
+    0x10: "most_recently_added",
+    0x80000010: "least_recently_added",
+    0x14: "most_often_played",
+    0x80000014: "least_often_played",
+    0x15: "most_recently_played",
+    0x80000015: "least_recently_played",
+    0x17: "highest_rating",
+    0x80000017: "lowest_rating",
+}
+
+
+# ============================================================
+# SLst — Smart Playlist Rules (MHOD type 51)
+# ============================================================
+# CRITICAL: The SLst blob is the ONLY part of the iTunesDB that uses
+# big-endian encoding. All multi-byte integers within SLst use big-endian.
+#
+# SLst header (136 bytes):
+#   +0x00: 'SLst' magic (4 bytes)
+#   +0x04: unk004 (4 bytes BE) — usually 0
+#   +0x08: rule_count (4 bytes BE)
+#   +0x0C: conjunction (4 bytes BE) — 0=AND, 1=OR
+#   +0x10: padding (120 bytes)
+#
+# All SLst header functions take body_offset = start of SLst data.
+
+SLST_HEADER_SIZE = 136
+
+
+def mhod_slst_magic(data, body_offset) -> bytes:
+    return data[body_offset:body_offset + 4]
+
+
+def mhod_slst_unk004(data, body_offset) -> int:
+    return struct.unpack(">I", data[body_offset + 4:body_offset + 8])[0]
+
+
+def mhod_slst_rule_count(data, body_offset) -> int:
+    return struct.unpack(">I", data[body_offset + 8:body_offset + 12])[0]
+
+
+def mhod_slst_conjunction(data, body_offset) -> int:
+    """0=AND (match all), 1=OR (match any)."""
+    return struct.unpack(">I", data[body_offset + 12:body_offset + 16])[0]
+
+
+# SPL Rule header fields.
+# Each rule starts at a variable offset within the SLst body.
+# Functions take rule_offset = start of the individual rule.
+#
+# Rule layout:
+#   +0x00: field (4 bytes BE) — what field to match (see SPL_FIELD_MAP)
+#   +0x04: action (4 bytes BE) — comparison operator (see SPL_ACTION_MAP)
+#   +0x08: padding (44 bytes)
+#   +0x34: data_length (4 bytes BE) — byte length of following data
+#   +0x38: data (data_length bytes)
+#
+# Total rule size = 56 + data_length.
+
+SPL_RULE_HEADER_SIZE = 56
+
+
+def mhod_spl_rule_field(data, rule_offset) -> int:
+    return struct.unpack(">I", data[rule_offset:rule_offset + 4])[0]
+
+
+def mhod_spl_rule_action(data, rule_offset) -> int:
+    return struct.unpack(">I", data[rule_offset + 4:rule_offset + 8])[0]
+
+
+def mhod_spl_rule_data_length(data, rule_offset) -> int:
+    return struct.unpack(">I", data[rule_offset + 0x34:rule_offset + 0x38])[0]
+
+
+# SPL Rule non-string data fields (0x44 = 68 bytes).
+# Functions take data_offset = rule_offset + 0x38.
+#
+#   +0x00: fromValue  (8 bytes BE, guint64)
+#   +0x08: fromDate   (8 bytes BE, gint64 — signed)
+#   +0x10: fromUnits  (8 bytes BE, guint64)
+#   +0x18: toValue    (8 bytes BE, guint64)
+#   +0x20: toDate     (8 bytes BE, gint64 — signed)
+#   +0x28: toUnits    (8 bytes BE, guint64)
+#   +0x30: unk052     (4 bytes BE)
+#   +0x34: unk056     (4 bytes BE)
+#   +0x38: unk060     (4 bytes BE)
+#   +0x3C: unk064     (4 bytes BE)
+#   +0x40: unk068     (4 bytes BE)
+
+def mhod_spl_rule_from_value(data, data_offset) -> int:
+    return struct.unpack(">Q", data[data_offset:data_offset + 8])[0]
+
+
+def mhod_spl_rule_from_date(data, data_offset) -> int:
+    """Signed 64-bit big-endian."""
+    return struct.unpack(">q", data[data_offset + 8:data_offset + 16])[0]
+
+
+def mhod_spl_rule_from_units(data, data_offset) -> int:
+    return struct.unpack(">Q", data[data_offset + 16:data_offset + 24])[0]
+
+
+def mhod_spl_rule_to_value(data, data_offset) -> int:
+    return struct.unpack(">Q", data[data_offset + 24:data_offset + 32])[0]
+
+
+def mhod_spl_rule_to_date(data, data_offset) -> int:
+    """Signed 64-bit big-endian."""
+    return struct.unpack(">q", data[data_offset + 32:data_offset + 40])[0]
+
+
+def mhod_spl_rule_to_units(data, data_offset) -> int:
+    return struct.unpack(">Q", data[data_offset + 40:data_offset + 48])[0]
+
+
+def mhod_spl_rule_unk052(data, data_offset) -> int:
+    return struct.unpack(">I", data[data_offset + 48:data_offset + 52])[0]
+
+
+def mhod_spl_rule_unk056(data, data_offset) -> int:
+    return struct.unpack(">I", data[data_offset + 52:data_offset + 56])[0]
+
+
+def mhod_spl_rule_unk060(data, data_offset) -> int:
+    return struct.unpack(">I", data[data_offset + 56:data_offset + 60])[0]
+
+
+def mhod_spl_rule_unk064(data, data_offset) -> int:
+    return struct.unpack(">I", data[data_offset + 60:data_offset + 64])[0]
+
+
+def mhod_spl_rule_unk068(data, data_offset) -> int:
+    return struct.unpack(">I", data[data_offset + 64:data_offset + 68])[0]
+
+
+# Field ID → human-readable name (from libgpod ItdbSPLField enum in itdb.h)
+SPL_FIELD_MAP = {
+    0x02: "Song Name",
+    0x03: "Album",
+    0x04: "Artist",
+    0x05: "Bitrate",
+    0x06: "Sample Rate",
+    0x07: "Year",
+    0x08: "Genre",
+    0x09: "Kind",
+    0x0A: "Date Modified",
+    0x0B: "Track Number",
+    0x0C: "Size",
+    0x0D: "Time",
+    0x0E: "Comment",
+    0x10: "Date Added",
+    0x12: "Composer",
+    0x16: "Play Count",
+    0x17: "Last Played",
+    0x18: "Disc Number",
+    0x19: "Rating",
+    0x1F: "Compilation",
+    0x23: "BPM",
+    0x27: "Grouping",
+    0x28: "Playlist",
+    0x29: "Purchased",
+    0x36: "Description",
+    0x37: "Category",
+    0x39: "Podcast",
+    0x3C: "Media Type",
+    0x3E: "TV Show",
+    0x3F: "Season Number",
+    0x44: "Skip Count",
+    0x45: "Last Skipped",
+    0x47: "Album Artist",
+    0x4E: "Sort Song Name",
+    0x4F: "Sort Album",
+    0x50: "Sort Artist",
+    0x51: "Sort Album Artist",
+    0x52: "Sort Composer",
+    0x53: "Sort TV Show",
+    0x5A: "Album Rating",
+}
+
+# Action ID → human-readable name (from libgpod ItdbSPLAction enum in itdb.h;
+# confirmed against iPodLinux wiki).
+# Actions are 32-bit bitmapped values, NOT small sequential integers.
+# Byte layout:
+#   Bits 24-25: 0x00=int/date, 0x01=string, 0x02=negated int, 0x03=negated string
+#   Bits 0-10:  comparison operator flags
+SPL_ACTION_MAP = {
+    # Integer / date comparisons (0x00xxxxxx)
+    0x00000001: "is",
+    0x00000010: "is greater than",
+    0x00000020: "is greater than or equal to",  # not in iTunes UI
+    0x00000040: "is less than",
+    0x00000080: "is less than or equal to",  # not in iTunes UI
+    0x00000100: "is in the range",
+    0x00000200: "is in the last",
+    0x00000400: "binary AND",  # used for Media Type / Video Kind
+    0x00000800: "binary unknown1",
+    # String comparisons (0x01xxxxxx)
+    0x01000001: "is (string)",
+    0x01000002: "contains",
+    0x01000004: "starts with",
+    0x01000008: "ends with",
+    # Negated integer / date (0x02xxxxxx)
+    0x02000001: "is not",
+    0x02000010: "is not greater than",  # not in iTunes UI
+    0x02000020: "is not greater than or equal to",  # not in iTunes UI
+    0x02000040: "is not less than",  # not in iTunes UI
+    0x02000080: "is not less than or equal to",  # not in iTunes UI
+    0x02000100: "is not in the range",  # not in iTunes UI
+    0x02000200: "is not in the last",
+    0x02000400: "not binary AND",
+    0x02000800: "binary unknown2",
+    # Negated string (0x03xxxxxx)
+    0x03000001: "is not (string)",
+    0x03000002: "does not contain",
+    0x03000004: "does not start with",  # not in iTunes UI
+    0x03000008: "does not end with",  # not in iTunes UI
+}
+
+# Field type enum (from libgpod ItdbSPLFieldType — values start at 1)
+SPLFT_STRING = 1
+SPLFT_INT = 2
+SPLFT_BOOLEAN = 3
+SPLFT_DATE = 4
+SPLFT_PLAYLIST = 5
+SPLFT_UNKNOWN = 6
+SPLFT_BINARY_AND = 7
+
+# Map field ID → field type (equivalent to libgpod's itdb_splr_get_field_type).
+# This is how libgpod determines how to parse the rule data — NOT from a binary field.
+SPL_FIELD_TYPE_MAP = {
+    # String fields
+    0x02: SPLFT_STRING,    # Song Name
+    0x03: SPLFT_STRING,    # Album
+    0x04: SPLFT_STRING,    # Artist
+    0x08: SPLFT_STRING,    # Genre
+    0x09: SPLFT_STRING,    # Kind
+    0x0E: SPLFT_STRING,    # Comment
+    0x12: SPLFT_STRING,    # Composer
+    0x27: SPLFT_STRING,    # Grouping
+    0x36: SPLFT_STRING,    # Description
+    0x37: SPLFT_STRING,    # Category
+    0x3E: SPLFT_STRING,    # TV Show
+    0x47: SPLFT_STRING,    # Album Artist
+    0x4E: SPLFT_STRING,    # Sort Song Name
+    0x4F: SPLFT_STRING,    # Sort Album
+    0x50: SPLFT_STRING,    # Sort Artist
+    0x51: SPLFT_STRING,    # Sort Album Artist
+    0x52: SPLFT_STRING,    # Sort Composer
+    0x53: SPLFT_STRING,    # Sort TV Show
+    # Integer fields
+    0x05: SPLFT_INT,       # Bitrate
+    0x06: SPLFT_INT,       # Sample Rate
+    0x07: SPLFT_INT,       # Year
+    0x0B: SPLFT_INT,       # Track Number
+    0x0C: SPLFT_INT,       # Size
+    0x0D: SPLFT_INT,       # Time
+    0x16: SPLFT_INT,       # Play Count
+    0x18: SPLFT_INT,       # Disc Number
+    0x19: SPLFT_INT,       # Rating
+    0x23: SPLFT_INT,       # BPM
+    0x3F: SPLFT_INT,       # Season Number
+    0x44: SPLFT_INT,       # Skip Count
+    0x5A: SPLFT_INT,       # Album Rating
+    # Date fields
+    0x0A: SPLFT_DATE,      # Date Modified
+    0x10: SPLFT_DATE,      # Date Added
+    0x17: SPLFT_DATE,      # Last Played
+    0x45: SPLFT_DATE,      # Last Skipped
+    # Boolean fields
+    0x1F: SPLFT_BOOLEAN,   # Compilation
+    0x29: SPLFT_BOOLEAN,   # Purchased
+    0x39: SPLFT_INT,       # Podcast
+    # Playlist field
+    0x28: SPLFT_PLAYLIST,  # Playlist
+    # Binary AND
+    0x3C: SPLFT_BINARY_AND,  # Video Kind
+}
+
+# Date units for relative date rules
+SPL_DATE_UNITS_MAP = {
+    1: "seconds",
+    60: "minutes",
+    3600: "hours",
+    86400: "days",
+    604800: "weeks",
+    2628000: "months",  # ~30.4 days
+}
+
+
+def spl_get_field_type(field_id: int) -> int:
+    """Determine SPL field type from field ID (equivalent to libgpod's itdb_splr_get_field_type)."""
+    return SPL_FIELD_TYPE_MAP.get(field_id, SPLFT_UNKNOWN)
+
+
+# ============================================================
+# MHOD Type 52/53 — Library Playlist Index / Jump Table
+# ============================================================
+# Both types share header structure (sort_type + count).
+# Functions take body_offset = start of body data (MHOD chunk + header_length).
+#
+# Type 52 layout:
+#   +0x00: sort_type (4 bytes LE) — 3=title, 4=album, 5=artist, 7=genre, 18=composer
+#   +0x04: count (4 bytes LE) — number of index entries
+#   +0x08: padding (40 bytes)
+#   +0x30: indices (count × 4 bytes LE) — sorted track positions
+#
+# Type 53 layout:
+#   +0x00: sort_type (4 bytes LE) — must match corresponding type 52
+#   +0x04: count (4 bytes LE) — number of jump entries
+#   +0x08: padding (8 bytes)
+#   +0x10: entries (count × 12 bytes):
+#          letter (2 bytes UTF-16 LE) + pad (2 bytes) + start (4 bytes) + count (4 bytes)
+
+SORT_TYPE_MAP = {
+    0x03: "title",
+    0x04: "album",          # then disc/track number, then title
+    0x05: "artist",         # then album, then disc/track number, then title
+    0x07: "genre",          # then artist, then album, then disc/track number, then title
+    0x12: "composer",       # then title
+    0x1D: "show",           # iTunes 7.2+; secondary sort TBD
+    0x1E: "season_number",  # iTunes 7.2+; secondary sort TBD
+    0x1F: "episode_number",  # iTunes 7.2+; secondary sort TBD
+    0x23: "album_artist",   # then artist (ignoring sort-artist), then album, disc/track, title
+    0x24: "artist_nosort",  # artist (ignoring sort-artist), then album, disc/track, title
+}
+
+
+def mhod52_sort_type(data, body_offset) -> int:
+    return struct.unpack("<I", data[body_offset:body_offset + 4])[0]
+
+
+def mhod52_count(data, body_offset) -> int:
+    return struct.unpack("<I", data[body_offset + 4:body_offset + 8])[0]
+
+
+def mhod53_sort_type(data, body_offset) -> int:
+    return struct.unpack("<I", data[body_offset:body_offset + 4])[0]
+
+
+def mhod53_count(data, body_offset) -> int:
+    return struct.unpack("<I", data[body_offset + 4:body_offset + 8])[0]
+
+
+# ============================================================
+# MHOD Type 100 — Playlist Position (MHIP context)
+# ============================================================
+# In MHIP context (body ≤ 20 bytes):
+#   +0x00: position (4 bytes LE) — 0-based track position in playlist
+
+def mhod100_position(data, body_offset) -> int:
+    return struct.unpack("<I", data[body_offset:body_offset + 4])[0]

src/vendor/iTunesDB_Shared/mhsd_defs.py

@@ -0,0 +1,15 @@
+"""MHSD (DataSet) field definitions.
+
+Declarative :class:`FieldDef` list for the MHSD chunk — a dataset
+container with a type field that determines its child.
+"""
+
+from .field_base import FieldDef, _u32
+
+_S = "mhsd"
+
+MHSD_HEADER_SIZE: int = 96
+
+MHSD_FIELDS: list[FieldDef] = [
+    _u32("dataset_type", 0x0C, section_type=_S, required=True),
+]

src/vendor/iTunesDB_Shared/mhyp_defs.py

@@ -0,0 +1,35 @@
+"""MHYP (Playlist) field definitions.
+
+Declarative :class:`FieldDef` list for the MHYP chunk — a single
+playlist record.
+"""
+
+from .field_base import FieldDef, _u8, _u16, _u32, _u64, mac_to_unix, unix_to_mac
+
+_S = "mhyp"
+
+MHYP_HEADER_SIZE: int = 184
+
+MHYP_FIELDS: list[FieldDef] = [
+    _u32("mhod_child_count", 0x0C, section_type=_S),
+    _u32("mhip_child_count", 0x10, section_type=_S),
+    _u8("master_flag", 0x14, section_type=_S),
+    _u8("flag1", 0x15, section_type=_S),
+    _u8("flag2", 0x16, section_type=_S),
+    _u8("flag3", 0x17, section_type=_S),
+    _u32("timestamp", 0x18, section_type=_S,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+    _u64("playlist_id", 0x1C, section_type=_S),
+    _u32("unk0x24", 0x24, section_type=_S),
+    _u16("string_mhod_child_count", 0x28, section_type=_S),
+    _u16("podcast_flag", 0x2A, section_type=_S),
+    _u32("sort_order", 0x2C, section_type=_S),
+    # Extended
+    _u64("db_id_2", 0x3C, section_type=_S, min_header_length=0x44),
+    _u64("playlist_id_2", 0x44, section_type=_S, min_header_length=0x4C),
+    _u16("mhsd5_type", 0x50, section_type=_S, min_header_length=0x52),
+    _u16("mhsd5_type_2", 0x52, section_type=_S, min_header_length=0x54),
+    _u32("mhsd5_special_flag", 0x54, section_type=_S, min_header_length=0x58),
+    _u32("timestamp_2", 0x58, section_type=_S, min_header_length=0x5C,
+         read_transform=mac_to_unix, write_transform=unix_to_mac),
+]

src/vendor/iTunesDB_Writer/__init__.py

@@ -0,0 +1,148 @@
+"""
+iTunesDB Writer module for iOpenPod.
+
+This module provides write support for iTunesDB (and iTunesCDB) files.
+
+Supported devices:
+- Pre-2007 iPods (1G-5G, Mini, Photo, Nano 1G-2G): No hash required
+- iPod Classic (all gens), Nano 3G, Nano 4G: HASH58 (needs FireWire ID)
+- iPod Nano 5G: HASH72 (requires HashInfo file from an iTunes sync)
+- iPod Nano 6G/7G: HASHAB (needs FireWire ID + WASM runtime)
+
+Usage:
+    from iTunesDB_Writer import write_checksum, detect_checksum_type
+
+    checksum_type = detect_checksum_type(ipod_path)
+    with open(itunesdb_path, 'rb') as f:
+        itdb_data = bytearray(f.read())
+
+    success = write_checksum(itdb_data, ipod_path)
+"""
+
+from ipod_device import ChecksumType
+from ipod_device import detect_checksum_type, get_firewire_id
+
+from .hash58 import (
+    compute_hash58,
+    write_hash58,
+)
+
+from .hash72 import (
+    compute_hash72,
+    write_hash72,
+    read_hash_info,
+    extract_hash_info,
+    extract_hash_info_to_dict,
+)
+
+from .hashab import (
+    compute_hashab,
+    write_hashab,
+)
+
+from .mhit_writer import TrackInfo, write_mhit
+from iTunesDB_Shared.constants import (
+    MEDIA_TYPE_AUDIO,
+    MEDIA_TYPE_VIDEO,
+    MEDIA_TYPE_PODCAST,
+    MEDIA_TYPE_VIDEO_PODCAST,
+    MEDIA_TYPE_AUDIOBOOK,
+    MEDIA_TYPE_MUSIC_VIDEO,
+    MEDIA_TYPE_TV_SHOW,
+    MEDIA_TYPE_RINGTONE,
+)
+from .mhyp_writer import PlaylistInfo, write_playlist, write_mhyp
+from .mhli_writer import write_mhli, write_mhii_artist, write_mhli_empty
+from .mhod_spl_writer import (
+    SmartPlaylistPrefs,
+    SmartPlaylistRules,
+    SmartPlaylistRule,
+    prefs_from_parsed,
+    rules_from_parsed,
+)
+from .mhbd_writer import write_itunesdb, write_mhbd, extract_db_info
+
+
+def write_checksum(itdb_data: bytearray, ipod_path: str) -> bool:
+    """
+    Write appropriate checksum to iTunesDB based on device type.
+
+    Args:
+        itdb_data: Mutable bytearray of complete iTunesDB file
+        ipod_path: Mount point of iPod
+
+    Returns:
+        True if checksum was written successfully
+
+    Raises:
+        ValueError: For unsupported devices
+    """
+    checksum_type = detect_checksum_type(ipod_path)
+
+    if checksum_type == ChecksumType.NONE:
+        # No hash needed
+        return True
+
+    elif checksum_type == ChecksumType.HASH58:
+        firewire_id = get_firewire_id(ipod_path)
+        write_hash58(itdb_data, firewire_id)
+        return True
+
+    elif checksum_type == ChecksumType.HASH72:
+        write_hash72(itdb_data, ipod_path)
+        return True
+
+    elif checksum_type == ChecksumType.HASHAB:
+        firewire_id = get_firewire_id(ipod_path)
+        write_hashab(itdb_data, firewire_id)
+        return True
+
+    else:
+        raise ValueError(
+            f"Unsupported checksum type: {checksum_type}."
+        )
+
+
+__all__ = [
+    'ChecksumType',
+    'detect_checksum_type',
+    'get_firewire_id',
+    'compute_hash58',
+    'write_hash58',
+    'compute_hash72',
+    'write_hash72',
+    'read_hash_info',
+    'extract_hash_info',
+    'extract_hash_info_to_dict',
+    'compute_hashab',
+    'write_hashab',
+    'write_checksum',
+    # Writer
+    'TrackInfo',
+    'write_mhit',
+    # Media type constants
+    'MEDIA_TYPE_AUDIO',
+    'MEDIA_TYPE_VIDEO',
+    'MEDIA_TYPE_PODCAST',
+    'MEDIA_TYPE_VIDEO_PODCAST',
+    'MEDIA_TYPE_AUDIOBOOK',
+    'MEDIA_TYPE_MUSIC_VIDEO',
+    'MEDIA_TYPE_TV_SHOW',
+    'MEDIA_TYPE_RINGTONE',
+    'write_mhbd',
+    'write_itunesdb',
+    'extract_db_info',
+    # Artist list
+    'write_mhli',
+    'write_mhii_artist',
+    'write_mhli_empty',
+    # Playlists
+    'PlaylistInfo',
+    'write_playlist',
+    'write_mhyp',
+    'SmartPlaylistPrefs',
+    'SmartPlaylistRules',
+    'SmartPlaylistRule',
+    'prefs_from_parsed',
+    'rules_from_parsed',
+]

src/vendor/iTunesDB_Writer/hash58.py

@@ -0,0 +1,280 @@
+"""
+HASH58 implementation for iPod Classic (all gens), Nano 3G, and Nano 4G.
+Ported from libgpod's itdb_hash58.c.
+
+This is the complete, working implementation for signing iTunesDB files
+for devices that use hashing_scheme=1 (HASH58).
+
+Usage:
+    from hash58 import write_hash58
+
+    with open("iTunesDB", "rb") as f:
+        itdb_data = bytearray(f.read())
+
+    firewire_id = bytes.fromhex("0011223344556677")  # From SysInfo
+    write_hash58(itdb_data, firewire_id)
+
+    with open("iTunesDB", "wb") as f:
+        f.write(itdb_data)
+"""
+
+import hashlib
+from math import gcd
+
+from iTunesDB_Shared.mhbd_defs import (
+    MHBD_OFFSET_DB_ID as OFFSET_DB_ID,
+    MHBD_OFFSET_HASHING_SCHEME as OFFSET_HASHING_SCHEME,
+    MHBD_OFFSET_UNK_0x32 as OFFSET_UNK_0x32,
+    MHBD_OFFSET_HASH58 as OFFSET_HASH58,
+)
+
+# AES S-Box (from libgpod itdb_hash58.c lines 45-76)
+TABLE1 = bytes([
+    0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5,
+    0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
+    0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0,
+    0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
+    0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC,
+    0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
+    0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A,
+    0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
+    0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0,
+    0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
+    0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B,
+    0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
+    0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85,
+    0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
+    0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5,
+    0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
+    0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17,
+    0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
+    0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88,
+    0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
+    0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C,
+    0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
+    0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9,
+    0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
+    0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6,
+    0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
+    0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E,
+    0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
+    0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94,
+    0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
+    0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68,
+    0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
+])
+
+# AES Inverse S-Box (from libgpod itdb_hash58.c lines 78-115)
+TABLE2 = bytes([
+    0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38,
+    0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
+    0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87,
+    0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
+    0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D,
+    0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
+    0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2,
+    0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
+    0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16,
+    0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
+    0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA,
+    0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
+    0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A,
+    0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
+    0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02,
+    0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
+    0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA,
+    0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
+    0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85,
+    0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
+    0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89,
+    0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
+    0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20,
+    0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
+    0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31,
+    0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
+    0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D,
+    0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
+    0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0,
+    0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
+    0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26,
+    0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
+])
+
+# Fixed bytes for key derivation (from libgpod itdb_hash58.c lines 113-115)
+FIXED = bytes([
+    0x67, 0x23, 0xFE, 0x30, 0x45, 0x33, 0xF8, 0x90, 0x99,
+    0x21, 0x07, 0xC1, 0xD0, 0x12, 0xB2, 0xA1, 0x07, 0x81
+])
+
+# Hash scheme identifier for HASH58
+ITDB_CHECKSUM_HASH58 = 1
+
+
+def _lcm(a: int, b: int) -> int:
+    """Least common multiple."""
+    if a == 0 or b == 0:
+        return 1
+    return (a * b) // gcd(a, b)
+
+
+def _generate_key(firewire_id: bytes) -> bytes:
+    """
+    Generate a 64-byte HMAC key from the 8-byte FireWire ID.
+
+    Algorithm:
+    1. Take LCM of each pair of consecutive bytes in the FireWire ID
+    2. Use the high and low bytes of each LCM to index into TABLE1 and TABLE2
+    3. SHA1 hash the FIXED bytes + derived bytes
+    4. Pad to 64 bytes
+    """
+    if len(firewire_id) < 8:
+        raise ValueError(f"FireWire ID must be at least 8 bytes, got {len(firewire_id)}")
+
+    y = bytearray(16)
+    for i in range(4):
+        a = firewire_id[i * 2]
+        b = firewire_id[i * 2 + 1]
+        cur_lcm = _lcm(a, b)
+
+        hi = (cur_lcm >> 8) & 0xFF
+        lo = cur_lcm & 0xFF
+
+        y[i * 4] = TABLE1[hi]
+        y[i * 4 + 1] = TABLE2[hi]
+        y[i * 4 + 2] = TABLE1[lo]
+        y[i * 4 + 3] = TABLE2[lo]
+
+    # SHA1(FIXED + y), then pad to 64 bytes
+    h = hashlib.sha1(FIXED + y).digest()
+    key = bytearray(64)
+    key[:len(h)] = h
+    return bytes(key)
+
+
+def compute_hash58(firewire_id: bytes, itdb_data: bytes) -> bytes:
+    """
+    Compute HMAC-SHA1 of iTunesDB data using FireWire ID-derived key.
+
+    This is a standard HMAC-SHA1 implementation with a custom key derivation.
+
+    Args:
+        firewire_id: 8-20 byte FireWire GUID from SysInfo
+        itdb_data: Complete iTunesDB file contents (with hash fields zeroed)
+
+    Returns:
+        20-byte SHA1 hash to write at offset 0x58
+    """
+    key = _generate_key(firewire_id)
+
+    # HMAC-SHA1: H(K XOR opad, H(K XOR ipad, message))
+    # Inner hash
+    inner_key = bytes(b ^ 0x36 for b in key)
+    inner_hash = hashlib.sha1(inner_key + itdb_data).digest()
+
+    # Outer hash
+    outer_key = bytes(b ^ 0x5c for b in key)
+    return hashlib.sha1(outer_key + inner_hash).digest()
+
+
+def write_hash58(itdb_data: bytearray, firewire_id: bytes) -> None:
+    """
+    Compute and write HASH58 checksum to iTunesDB data in-place.
+
+    From libgpod itdb_hash58_write_hash():
+    1. Backs up db_id and unk_0x32 fields
+    2. Zeros out db_id, unk_0x32, and hash58 fields (required for hash computation)
+    3. Sets hashing_scheme to HASH58 (1)
+    4. Computes HMAC-SHA1 hash
+    5. Writes hash to offset 0x58
+    6. Restores backed up fields
+
+    NOTE: Unlike HASH72, HASH58 zeros unk_0x32 before computing the hash!
+    This is a key difference between the two algorithms.
+
+    Args:
+        itdb_data: Mutable bytearray of complete iTunesDB file
+        firewire_id: 8-20 byte FireWire GUID from /iPod_Control/Device/SysInfo
+
+    Raises:
+        ValueError: If iTunesDB is too small or FireWire ID is invalid
+    """
+    if len(itdb_data) < 0x6C:
+        raise ValueError(f"iTunesDB file too small ({len(itdb_data)} bytes), need at least 0x6C")
+
+    # Verify this is an mhbd header
+    if itdb_data[:4] != b'mhbd':
+        raise ValueError("Invalid iTunesDB: expected 'mhbd' header")
+
+    # Backup fields that will be zeroed
+    backup_db_id = bytes(itdb_data[OFFSET_DB_ID:OFFSET_DB_ID + 8])
+    backup_unk32 = bytes(itdb_data[OFFSET_UNK_0x32:OFFSET_UNK_0x32 + 20])
+
+    # Zero out fields for hash computation
+    itdb_data[OFFSET_DB_ID:OFFSET_DB_ID + 8] = b'\x00' * 8
+    itdb_data[OFFSET_UNK_0x32:OFFSET_UNK_0x32 + 20] = b'\x00' * 20
+    itdb_data[OFFSET_HASH58:OFFSET_HASH58 + 20] = b'\x00' * 20
+
+    # Set hashing scheme to HASH58
+    itdb_data[OFFSET_HASHING_SCHEME:OFFSET_HASHING_SCHEME + 2] = \
+        ITDB_CHECKSUM_HASH58.to_bytes(2, 'little')
+
+    # Compute and write hash
+    hash_val = compute_hash58(firewire_id, bytes(itdb_data))
+    if len(hash_val) != 20:
+        raise RuntimeError(f"Hash computation failed: expected 20 bytes, got {len(hash_val)}")
+    itdb_data[OFFSET_HASH58:OFFSET_HASH58 + 20] = hash_val
+
+    # Restore backed up fields
+    itdb_data[OFFSET_DB_ID:OFFSET_DB_ID + 8] = backup_db_id
+    itdb_data[OFFSET_UNK_0x32:OFFSET_UNK_0x32 + 20] = backup_unk32
+
+
+def read_firewire_id(ipod_path: str) -> bytes:
+    """Return the FireWire GUID for the connected iPod.
+
+    Reads from the centralised DeviceInfo store.  Raises if not available.
+    """
+    from ipod_device import get_current_device
+    device = get_current_device()
+    if device is not None:
+        fwid = device.firewire_id_bytes
+        if fwid:
+            return fwid
+    raise RuntimeError(
+        "FireWire GUID not available. Device info was not populated "
+        "by the device scanner."
+    )
+
+
+if __name__ == "__main__":
+    # Example usage
+    import sys
+
+    if len(sys.argv) < 3:
+        print("Usage: python hash58.py <ipod_path> <itunesdb_path>")
+        print("Example: python hash58.py E: E:/iPod_Control/iTunes/iTunesDB")
+        sys.exit(1)
+
+    ipod_path = sys.argv[1]
+    itunesdb_path = sys.argv[2]
+
+    try:
+        firewire_id = read_firewire_id(ipod_path)
+        print(f"FireWire ID: {firewire_id.hex()}")
+
+        with open(itunesdb_path, 'rb') as f:
+            itdb_data = bytearray(f.read())
+
+        print(f"Read {len(itdb_data)} bytes from iTunesDB")
+
+        write_hash58(itdb_data, firewire_id)
+        print("Hash computed successfully!")
+
+        # Write back (uncomment to actually write)
+        # with open(itunesdb_path, 'wb') as f:
+        #     f.write(itdb_data)
+        # print("iTunesDB updated!")
+
+    except Exception as e:
+        print(f"Error: {e}")
+        sys.exit(1)

src/vendor/iTunesDB_Writer/hash72.py

@@ -0,0 +1,476 @@
+"""
+HASH72 implementation for iPod Nano 5G.
+Ported from libgpod's itdb_hash72.c.
+
+Note: iTunes also writes a HASH72 signature on iPod Classic devices, but
+the Classic firmware only checks HASH58 (scheme=1).  We preserve HASH72
+from a reference database when available but do not require it for Classic.
+
+IMPORTANT: This requires a HashInfo file that must be extracted from a valid
+iTunes sync. The HashInfo file contains the IV and random bytes needed to
+generate signatures.
+
+If you don't have a HashInfo file:
+1. Sync once with iTunes (creates /iPod_Control/Device/HashInfo)
+2. OR use extract_hash_info() with a known-good iTunesDB from iTunes
+
+Usage:
+    from hash72 import write_hash72
+
+    with open("iTunesDB", "rb") as f:
+        itdb_data = bytearray(f.read())
+
+    # Requires HashInfo file to exist at /iPod_Control/Device/HashInfo
+    write_hash72(itdb_data, ipod_path="/media/ipod")
+
+    with open("iTunesDB", "wb") as f:
+        f.write(itdb_data)
+"""
+
+import hashlib
+import os
+from typing import Optional
+
+from iTunesDB_Shared.mhbd_defs import (
+    MHBD_OFFSET_DB_ID as OFFSET_DB_ID,
+    MHBD_OFFSET_HASHING_SCHEME as OFFSET_HASHING_SCHEME,
+    MHBD_OFFSET_HASH58 as OFFSET_HASH58,
+    MHBD_OFFSET_HASH72 as OFFSET_HASH72,
+)
+
+# AES-128 key (from libgpod itdb_hash72.c line 40)
+AES_KEY = bytes([
+    0x61, 0x8c, 0xa1, 0x0d, 0xc7, 0xf5, 0x7f, 0xd3,
+    0xb4, 0x72, 0x3e, 0x08, 0x15, 0x74, 0x63, 0xd7
+])
+
+# Hash scheme identifier for HASH72
+ITDB_CHECKSUM_HASH72 = 2
+
+# HashInfo file structure
+HASHINFO_HEADER = b"HASHv0"
+HASHINFO_HEADER_LEN = 6
+HASHINFO_UUID_LEN = 20
+HASHINFO_RNDPART_LEN = 12
+HASHINFO_IV_LEN = 16
+
+
+class HashInfo:
+    """Parsed HashInfo file data."""
+
+    def __init__(self, uuid: bytes, rndpart: bytes, iv: bytes):
+        self.uuid = uuid
+        self.rndpart = rndpart
+        self.iv = iv
+
+
+def _get_hash_info_path(ipod_path: str) -> str:
+    """Get path to HashInfo file."""
+    return os.path.join(ipod_path, "iPod_Control", "Device", "HashInfo")
+
+
+def read_hash_info(ipod_path: str) -> Optional[HashInfo]:
+    """
+    Read and parse HashInfo file from iPod.
+
+    HashInfo structure (54 bytes total):
+    - header[6]: "HASHv0"
+    - uuid[20]: Device UUID (should match FirewireGuid)
+    - rndpart[12]: Random bytes for signature
+    - iv[16]: AES initialization vector
+
+    Args:
+        ipod_path: Mount point of iPod
+
+    Returns:
+        HashInfo object or None if file doesn't exist
+    """
+    # Check centralized device_info store first
+    try:
+        from ipod_device import get_current_device
+        dev = get_current_device()
+        if dev and dev.hash_info_iv and dev.hash_info_rndpart:
+            return HashInfo(uuid=b'\x00' * 20, rndpart=dev.hash_info_rndpart, iv=dev.hash_info_iv)
+    except Exception:
+        pass
+
+    # Fallback: read from disk
+    path = _get_hash_info_path(ipod_path)
+
+    if not os.path.exists(path):
+        return None
+
+    with open(path, 'rb') as f:
+        data = f.read()
+
+    if len(data) < 54:
+        return None
+
+    if data[:6] != HASHINFO_HEADER:
+        return None
+
+    # Parse structure
+    uuid = data[6:26]
+    rndpart = data[26:38]
+    iv = data[38:54]
+
+    return HashInfo(uuid, rndpart, iv)
+
+
+def write_hash_info(ipod_path: str, uuid: bytes, iv: bytes, rndpart: bytes) -> bool:
+    """
+    Write HashInfo file to iPod.
+
+    Args:
+        ipod_path: Mount point of iPod
+        uuid: 20-byte device UUID
+        iv: 16-byte AES IV
+        rndpart: 12-byte random bytes
+
+    Returns:
+        True if successful
+    """
+    if len(uuid) != 20 or len(iv) != 16 or len(rndpart) != 12:
+        return False
+
+    data = HASHINFO_HEADER + uuid + rndpart + iv
+
+    path = _get_hash_info_path(ipod_path)
+    device_dir = os.path.dirname(path)
+    os.makedirs(device_dir, exist_ok=True)
+
+    with open(path, 'wb') as f:
+        f.write(data)
+
+    return True
+
+
+def _compute_itunesdb_sha1(itdb_data: bytearray) -> bytes:
+    """
+    Compute SHA1 of iTunesDB with hash fields zeroed.
+
+    From libgpod itdb_hash72_compute_itunesdb_sha1():
+    - db_id (offset 0x18, 8 bytes) is zeroed
+    - hash58 (offset 0x58, 20 bytes) is zeroed
+    - hash72 (offset 0x72, 46 bytes) is zeroed
+
+    NOTE: Unlike HASH58, unk_0x32 is NOT zeroed for HASH72!
+    libgpod backs it up and restores it, but since it's never zeroed,
+    we don't need to do anything with it.
+    """
+    # Work on a copy to avoid modifying original
+    data = bytearray(itdb_data)
+
+    # Zero fields for hash computation (same as libgpod)
+    # hash58 lives at offset 0x58 (20 bytes), hash72 at 0x72 (46 bytes)
+    data[OFFSET_DB_ID:OFFSET_DB_ID + 8] = b'\x00' * 8
+    data[OFFSET_HASH58:OFFSET_HASH58 + 20] = b'\x00' * 20
+    data[OFFSET_HASH72:OFFSET_HASH72 + 46] = b'\x00' * 46
+
+    return hashlib.sha1(bytes(data)).digest()
+
+
+def _hash_generate(sha1: bytes, iv: bytes, rndpart: bytes) -> bytes:
+    """
+    Generate 46-byte signature using AES encryption.
+
+    Signature format:
+    - bytes 0-1: 0x01 0x00 (prefix)
+    - bytes 2-13: rndpart (12 bytes)
+    - bytes 14-45: AES-CBC encrypted (sha1 + rndpart) (32 bytes)
+
+    Args:
+        sha1: 20-byte SHA1 of iTunesDB
+        iv: 16-byte initialization vector
+        rndpart: 12-byte random bytes
+
+    Returns:
+        46-byte signature
+    """
+    try:
+        from Crypto.Cipher import AES
+    except ImportError:
+        try:
+            from Cryptodome.Cipher import AES  # type: ignore[import-not-found]
+        except ImportError:
+            raise ImportError(
+                "PyCryptodome is required for HASH72. "
+                "Install with: pip install pycryptodome"
+            )
+
+    # Plaintext: sha1 (20 bytes) + rndpart (12 bytes) = 32 bytes
+    plaintext = sha1 + rndpart
+
+    # AES-CBC encrypt
+    cipher = AES.new(AES_KEY, AES.MODE_CBC, iv)
+    encrypted = cipher.encrypt(plaintext)
+
+    # Build signature
+    signature = bytearray(46)
+    signature[0] = 0x01
+    signature[1] = 0x00
+    signature[2:14] = rndpart
+    signature[14:46] = encrypted
+
+    return bytes(signature)
+
+
+def _hash_extract(signature: bytes, sha1: bytes) -> Optional[tuple]:
+    """
+    Extract IV and random bytes from a valid signature.
+
+    This can be used to create a HashInfo file from a known-good
+    iTunes-generated iTunesDB.
+
+    Algorithm from libgpod itdb_hash72.c hash_extract():
+
+    The signature was created by:
+        C = AES_encrypt_CBC(plaintext, IV) where plaintext = sha1 + rndpart
+
+    In CBC mode, the first block is:
+        C_0 = AES_encrypt(P_0 XOR IV) where P_0 = sha1[:16]
+
+    To recover IV, we decrypt C_0 using sha1[:16] as a fake IV:
+        output = AES_decrypt(C_0) XOR sha1[:16]
+               = (P_0 XOR IV) XOR sha1[:16]
+               = (sha1[:16] XOR IV) XOR sha1[:16]
+               = IV
+
+    The libgpod code also does a sanity check comparing plaintext[16:32]
+    to output[16:32], but since only the first 16 bytes are decrypted,
+    output[16:32] is always equal to plaintext[16:32]. We keep this check
+    for compatibility.
+
+    Args:
+        signature: 46-byte signature from valid iTunesDB
+        sha1: 20-byte SHA1 that was used to generate the signature
+
+    Returns:
+        (iv, rndpart) tuple or None if invalid
+    """
+    try:
+        from Crypto.Cipher import AES
+    except ImportError:
+        try:
+            from Cryptodome.Cipher import AES  # type: ignore[import-not-found]
+        except ImportError:
+            raise ImportError(
+                "PyCryptodome is required for HASH72. "
+                "Install with: pip install pycryptodome"
+            )
+
+    if len(signature) < 46 or signature[0] != 0x01 or signature[1] != 0x00:
+        return None
+
+    # Build plaintext = sha1 + rndpart (matches libgpod)
+    rndpart = signature[2:14]
+    plaintext = bytearray(32)
+    plaintext[:20] = sha1
+    plaintext[20:32] = rndpart
+
+    # Initialize output as copy of plaintext (matches libgpod: memcpy(output, plaintext, 32))
+    output = bytearray(plaintext)
+
+    # AES-CBC decrypt first 16 bytes only, using sha1[:16] as IV
+    # This recovers the real IV through the XOR cancellation described above
+    cipher = AES.new(AES_KEY, AES.MODE_CBC, bytes(plaintext[:16]))
+    decrypted_block = cipher.decrypt(bytes(signature[14:30]))
+    output[:16] = decrypted_block
+
+    # Sanity check from libgpod - always passes since output[16:32] was
+    # copied from plaintext[16:32] and never modified
+    if bytes(plaintext[16:32]) != bytes(output[16:32]):
+        return None
+
+    # The IV is now in output[:16]
+    iv = bytes(output[:16])
+
+    return (iv, bytes(rndpart))
+
+
+def extract_hash_info(ipod_path: str, valid_itdb_data: bytes) -> bool:
+    """
+    Extract HashInfo from a valid iTunes-generated iTunesDB.
+
+    Use this when you have an iTunesDB that was created by iTunes
+    but you don't have a HashInfo file.
+
+    Args:
+        ipod_path: Mount point of iPod
+        valid_itdb_data: Contents of valid iTunes-generated iTunesDB
+
+    Returns:
+        True if HashInfo was successfully extracted and saved
+    """
+    if len(valid_itdb_data) < 0xA0:
+        return False
+
+    if valid_itdb_data[:4] != b'mhbd':
+        return False
+
+    # Get existing hash72 from CORRECT offset (0x72)
+    hash72 = bytes(valid_itdb_data[OFFSET_HASH72:OFFSET_HASH72 + 46])
+
+    # Check for valid signature marker
+    if hash72[0:2] != bytes([0x01, 0x00]):
+        # Not a valid hash72 signature
+        return False
+
+    # Compute SHA1
+    itdb_copy = bytearray(valid_itdb_data)
+    sha1 = _compute_itunesdb_sha1(itdb_copy)
+
+    # Extract IV and rndpart
+    result = _hash_extract(hash72, sha1)
+    if result is None:
+        return False
+
+    iv, rndpart = result
+
+    # Get UUID from device (or use zeros if not available)
+    try:
+        from .hash58 import read_firewire_id
+        fw_id = read_firewire_id(ipod_path)
+        uuid = bytearray(20)
+        uuid[:len(fw_id)] = fw_id
+    except Exception:
+        uuid = bytes(20)
+
+    return write_hash_info(ipod_path, bytes(uuid), iv, rndpart)
+
+
+def extract_hash_info_to_dict(valid_itdb_data: bytes) -> dict | None:
+    """
+    Extract HashInfo from a valid iTunes-generated iTunesDB.
+
+    Returns the extracted info as a dict instead of writing to disk.
+
+    Args:
+        valid_itdb_data: Contents of valid iTunes-generated iTunesDB
+
+    Returns:
+        Dict with 'iv' and 'rndpart' keys, or None if extraction failed
+    """
+    if len(valid_itdb_data) < 0xA0:
+        return None
+
+    if valid_itdb_data[:4] != b'mhbd':
+        return None
+
+    # Get existing hash72 from CORRECT offset (0x72)
+    hash72 = bytes(valid_itdb_data[OFFSET_HASH72:OFFSET_HASH72 + 46])
+
+    # Check for valid signature marker
+    if hash72[0:2] != bytes([0x01, 0x00]):
+        return None
+
+    # Compute SHA1
+    itdb_copy = bytearray(valid_itdb_data)
+    sha1 = _compute_itunesdb_sha1(itdb_copy)
+
+    # Extract IV and rndpart
+    result = _hash_extract(hash72, sha1)
+    if result is None:
+        return None
+
+    iv, rndpart = result
+    return {'iv': iv, 'rndpart': rndpart}
+
+
+def compute_hash72(ipod_path: str, itdb_data: bytes) -> bytes:
+    """
+    Compute HASH72 signature for iTunesDB data.
+
+    Args:
+        ipod_path: Mount point of iPod (for reading HashInfo)
+        itdb_data: Complete iTunesDB file contents
+
+    Returns:
+        46-byte signature
+
+    Raises:
+        FileNotFoundError: If HashInfo file doesn't exist
+    """
+    hash_info = read_hash_info(ipod_path)
+    if hash_info is None:
+        raise FileNotFoundError(
+            f"HashInfo file not found at {_get_hash_info_path(ipod_path)}. "
+            "Sync once with iTunes to create it, or use extract_hash_info() "
+            "with a valid iTunes-generated iTunesDB."
+        )
+
+    sha1 = _compute_itunesdb_sha1(bytearray(itdb_data))
+    return _hash_generate(sha1, hash_info.iv, hash_info.rndpart)
+
+
+def write_hash72(itdb_data: bytearray, ipod_path: str) -> None:
+    """
+    Compute and write HASH72 checksum to iTunesDB data in-place.
+
+    Args:
+        itdb_data: Mutable bytearray of complete iTunesDB file
+        ipod_path: Mount point of iPod (for reading HashInfo)
+
+    Raises:
+        ValueError: If iTunesDB is too small
+        FileNotFoundError: If HashInfo file doesn't exist
+    """
+    if len(itdb_data) < 0x6C:
+        raise ValueError(f"iTunesDB file too small ({len(itdb_data)} bytes)")
+
+    if itdb_data[:4] != b'mhbd':
+        raise ValueError("Invalid iTunesDB: expected 'mhbd' header")
+
+    # Set hashing scheme
+    itdb_data[OFFSET_HASHING_SCHEME:OFFSET_HASHING_SCHEME + 2] = \
+        ITDB_CHECKSUM_HASH72.to_bytes(2, 'little')
+
+    # Compute and write signature
+    signature = compute_hash72(ipod_path, bytes(itdb_data))
+    itdb_data[OFFSET_HASH72:OFFSET_HASH72 + 46] = signature
+
+
+if __name__ == "__main__":
+    import sys
+
+    if len(sys.argv) < 3:
+        print("Usage: python hash72.py <ipod_path> <itunesdb_path>")
+        print("Example: python hash72.py /media/ipod /media/ipod/iPod_Control/iTunes/iTunesDB")
+        sys.exit(1)
+
+    ipod_path = sys.argv[1]
+    itunesdb_path = sys.argv[2]
+
+    try:
+        # Check for HashInfo
+        hash_info = read_hash_info(ipod_path)
+        if hash_info:
+            print(f"HashInfo found: IV={hash_info.iv.hex()[:16]}...")
+        else:
+            print("HashInfo not found. Attempting to extract from iTunesDB...")
+            with open(itunesdb_path, 'rb') as f:
+                itdb_data = f.read()
+            if extract_hash_info(ipod_path, itdb_data):
+                print("HashInfo extracted and saved successfully!")
+            else:
+                print("Failed to extract HashInfo. Sync with iTunes first.")
+                sys.exit(1)
+
+        with open(itunesdb_path, 'rb') as f:
+            itdb_data = bytearray(f.read())
+
+        print(f"Read {len(itdb_data)} bytes from iTunesDB")
+
+        write_hash72(itdb_data, ipod_path)
+        print("Hash computed successfully!")
+
+        # Write back (uncomment to actually write)
+        # with open(itunesdb_path, 'wb') as f:
+        #     f.write(itdb_data)
+        # print("iTunesDB updated!")
+
+    except Exception as e:
+        print(f"Error: {e}")
+        import traceback
+        traceback.print_exc()
+        sys.exit(1)

src/vendor/iTunesDB_Writer/hashab.py

@@ -0,0 +1,287 @@
+"""
+HASHAB implementation for iPod Nano 6G and 7G.
+
+Uses a WebAssembly module (calcHashAB.wasm) from dstaley/hashab — a clean-room
+reimplementation of Apple's white-box AES signing algorithm.  The WASM binary
+is executed via wasmtime-py, giving cross-platform support without compiling
+native code.
+
+Algorithm overview (4 phases inside the WASM module):
+  1. CBC-MAC compression of UUID with AES
+  2. Key material expansion (44 → 190 bytes)
+  3. Initial buffer generation (190 → 16 bytes)
+  4. White-box AES-128 encryption
+
+The output is a 57-byte signature written at mhbd offset 0xAB.  This is
+analogous to HASH58 (20 bytes at 0x58) and HASH72 (46 bytes at 0x72).
+
+Source: https://github.com/dstaley/hashab (The Unlicense)
+WASM release: https://github.com/dstaley/hashab/releases/tag/2025-01-04
+
+Usage:
+    from hashab import write_hashab
+
+    with open("iTunesDB", "rb") as f:
+        itdb_data = bytearray(f.read())
+
+    firewire_id = bytes.fromhex("0011223344556677")  # From SysInfo
+    write_hashab(itdb_data, firewire_id)
+
+    with open("iTunesDB", "wb") as f:
+        f.write(itdb_data)
+"""
+
+import hashlib
+import logging
+from pathlib import Path
+
+from iTunesDB_Shared.mhbd_defs import (
+    MHBD_OFFSET_DB_ID as OFFSET_DB_ID,
+    MHBD_OFFSET_HASHING_SCHEME as OFFSET_HASHING_SCHEME,
+    MHBD_OFFSET_UNK_0x32 as OFFSET_UNK_0x32,
+    MHBD_OFFSET_HASH58 as OFFSET_HASH58,
+    MHBD_OFFSET_HASH72 as OFFSET_HASH72,
+    MHBD_OFFSET_HASHAB as OFFSET_HASHAB,
+)
+
+logger = logging.getLogger(__name__)
+
+HASHAB_SIZE = 57
+ITDB_CHECKSUM_HASHAB = 4     # hashing_scheme value for HASHAB
+
+# Path to the WASM module (shipped alongside this file)
+_WASM_DIR = Path(__file__).parent / "wasm"
+_WASM_PATH = _WASM_DIR / "calcHashAB.wasm"
+
+# Lazy-loaded WASM engine (expensive to create — reuse across calls)
+_wasm_instance = None
+_wasm_store = None
+
+
+def _get_wasm_instance():
+    """Load the WASM module and return (store, instance).
+
+    The module exports:
+      memory         — linear memory
+      getInputSha1() — returns pointer to 20-byte SHA1 input buffer
+      getInputUuid() — returns pointer to 8-byte UUID input buffer
+      getOutput()    — returns pointer to 57-byte output buffer
+      calculateHash()— run the hash computation
+    """
+    global _wasm_instance, _wasm_store
+
+    if _wasm_instance is not None:
+        return _wasm_store, _wasm_instance
+
+    try:
+        import wasmtime
+    except ImportError:
+        raise ImportError(
+            "wasmtime is required for HASHAB (iPod Nano 6G/7G). "
+            "Install with: uv add wasmtime   or   pip install wasmtime"
+        )
+
+    if not _WASM_PATH.exists():
+        raise FileNotFoundError(
+            f"WASM module not found at {_WASM_PATH}. "
+            "Download calcHashAB.wasm from "
+            "https://github.com/dstaley/hashab/releases/tag/2025-01-04"
+        )
+
+    engine = wasmtime.Engine()
+    store = wasmtime.Store(engine)
+    module = wasmtime.Module.from_file(engine, str(_WASM_PATH))
+    instance = wasmtime.Instance(store, module, [])
+
+    _wasm_store = store
+    _wasm_instance = instance
+
+    logger.debug("HASHAB WASM module loaded from %s", _WASM_PATH)
+    return store, instance
+
+
+def compute_hashab(sha1_digest: bytes, uuid: bytes) -> bytes:
+    """
+    Compute 57-byte HASHAB signature using the WASM module.
+
+    Args:
+        sha1_digest: 20-byte SHA1 hash of the iTunesDB (with hash fields zeroed)
+        uuid: 8-byte FireWire GUID / UUID from SysInfo
+
+    Returns:
+        57-byte signature to write at mhbd offset 0xAB
+    """
+    if len(sha1_digest) != 20:
+        raise ValueError(f"SHA1 must be 20 bytes, got {len(sha1_digest)}")
+    if len(uuid) < 8:
+        raise ValueError(f"UUID must be at least 8 bytes, got {len(uuid)}")
+
+    store, instance = _get_wasm_instance()
+
+    # Get exported functions and memory
+    # wasmtime stubs type exports() return as a union; runtime types are correct
+    exports = instance.exports(store)  # type: ignore[arg-type]
+    memory = exports["memory"]
+    get_input_sha1 = exports["getInputSha1"]
+    get_input_uuid = exports["getInputUuid"]
+    get_output = exports["getOutput"]
+    calculate_hash = exports["calculateHash"]
+
+    # Get pointers into WASM linear memory
+    sha1_ptr = get_input_sha1(store)  # type: ignore[misc]
+    uuid_ptr = get_input_uuid(store)  # type: ignore[misc]
+    output_ptr = get_output(store)  # type: ignore[misc]
+
+    # Write inputs into WASM memory
+    mem_data = memory.data_ptr(store)  # type: ignore[union-attr]
+
+    # Write SHA1 (20 bytes)
+    for i in range(20):
+        mem_data[sha1_ptr + i] = sha1_digest[i]
+
+    # Write UUID (8 bytes)
+    for i in range(8):
+        mem_data[uuid_ptr + i] = uuid[i]
+
+    # Execute the hash computation
+    calculate_hash(store)  # type: ignore[misc]
+
+    # Read 57-byte output
+    result = bytes(mem_data[output_ptr + i] for i in range(HASHAB_SIZE))
+
+    logger.debug("HASHAB computed: %s…", result[:4].hex())
+    return result
+
+
+def _compute_itunesdb_sha1_for_hashab(itdb_data: bytearray) -> bytes:
+    """
+    Compute SHA1 of iTunesDB with all hash fields zeroed for HASHAB.
+
+    Zeroed fields before hashing:
+    - db_id      (offset 0x18, 8 bytes)
+    - unk_0x32   (offset 0x32, 20 bytes)
+    - hash58     (offset 0x58, 20 bytes)
+    - hash72     (offset 0x72, 46 bytes)
+    - hashAB     (offset 0xAB, 57 bytes)
+
+    We zero unk_0x32 (matching HASH58 behavior) because HASHAB devices
+    (Nano 6G/7G) also maintain hash58 compatibility fields.
+    """
+    data = bytearray(itdb_data)
+
+    data[OFFSET_DB_ID:OFFSET_DB_ID + 8] = b'\x00' * 8
+    data[OFFSET_UNK_0x32:OFFSET_UNK_0x32 + 20] = b'\x00' * 20
+    data[OFFSET_HASH58:OFFSET_HASH58 + 20] = b'\x00' * 20
+    data[OFFSET_HASH72:OFFSET_HASH72 + 46] = b'\x00' * 46
+    data[OFFSET_HASHAB:OFFSET_HASHAB + HASHAB_SIZE] = b'\x00' * HASHAB_SIZE
+
+    return hashlib.sha1(bytes(data)).digest()
+
+
+def write_hashab(itdb_data: bytearray, firewire_id: bytes) -> None:
+    """
+    Compute and write HASHAB signature to iTunesDB data in-place.
+
+    Steps:
+    1. Zero db_id, unk_0x32, hash58, hash72, hashAB
+    2. Set hashing_scheme to 4 (HASHAB)
+    3. Compute SHA1 of entire database
+    4. Call WASM module with SHA1 + UUID
+    5. Write 57-byte result at offset 0xAB
+    6. Restore backed-up fields
+
+    Args:
+        itdb_data: Mutable bytearray of complete iTunesDB file
+        firewire_id: 8+ byte FireWire GUID from /iPod_Control/Device/SysInfo
+
+    Raises:
+        ValueError: If iTunesDB is too small or FireWire ID is invalid
+    """
+    min_size = OFFSET_HASHAB + HASHAB_SIZE  # 0xAB + 57 = 0xE4 = 228
+    if len(itdb_data) < min_size:
+        raise ValueError(
+            f"iTunesDB file too small ({len(itdb_data)} bytes), "
+            f"need at least {min_size} (0x{min_size:X})"
+        )
+
+    if itdb_data[:4] != b'mhbd':
+        raise ValueError("Invalid iTunesDB: expected 'mhbd' header")
+
+    if len(firewire_id) < 8:
+        raise ValueError(
+            f"FireWire ID must be at least 8 bytes, got {len(firewire_id)}"
+        )
+
+    # Backup fields that will be zeroed for SHA1 computation
+    backup_db_id = bytes(itdb_data[OFFSET_DB_ID:OFFSET_DB_ID + 8])
+    backup_unk32 = bytes(itdb_data[OFFSET_UNK_0x32:OFFSET_UNK_0x32 + 20])
+
+    # Set hashing scheme to HASHAB (4)
+    itdb_data[OFFSET_HASHING_SCHEME:OFFSET_HASHING_SCHEME + 2] = \
+        ITDB_CHECKSUM_HASHAB.to_bytes(2, 'little')
+
+    # Compute SHA1 with hash fields zeroed
+    sha1_digest = _compute_itunesdb_sha1_for_hashab(itdb_data)
+
+    # Compute HASHAB via WASM
+    signature = compute_hashab(sha1_digest, firewire_id[:8])
+
+    if len(signature) != HASHAB_SIZE:
+        raise RuntimeError(
+            f"WASM returned {len(signature)} bytes, expected {HASHAB_SIZE}"
+        )
+
+    # Write signature to mhbd header
+    itdb_data[OFFSET_HASHAB:OFFSET_HASHAB + HASHAB_SIZE] = signature
+
+    # Restore backed-up fields
+    itdb_data[OFFSET_DB_ID:OFFSET_DB_ID + 8] = backup_db_id
+    itdb_data[OFFSET_UNK_0x32:OFFSET_UNK_0x32 + 20] = backup_unk32
+
+    logger.info("HASHAB signature written at offset 0x%X (%d bytes)",
+                OFFSET_HASHAB, HASHAB_SIZE)
+
+
+def read_firewire_id(ipod_path: str) -> bytes:
+    """Return the FireWire GUID for the connected iPod.
+
+    Reads from the centralised DeviceInfo store.  Raises if not available.
+    """
+    from ipod_device import get_current_device
+    device = get_current_device()
+    if device is not None:
+        fwid = device.firewire_id_bytes
+        if fwid:
+            return fwid
+    raise RuntimeError(
+        "FireWire GUID not available. Device info was not populated "
+        "by the device scanner."
+    )
+
+
+if __name__ == "__main__":
+    import sys
+
+    if len(sys.argv) < 3:
+        print("Usage: python hashab.py <ipod_path> <itunesdb_path>")
+        print("Example: python hashab.py /media/ipod /media/ipod/iPod_Control/iTunes/iTunesDB")
+        sys.exit(1)
+
+    ipod_path = sys.argv[1]
+    itunesdb_path = sys.argv[2]
+
+    try:
+        firewire_id = read_firewire_id(ipod_path)
+        print(f"FireWire ID: {firewire_id.hex()}")
+
+        with open(itunesdb_path, 'rb') as f:
+            itdb_data = bytearray(f.read())
+
+        print(f"Read {len(itdb_data)} bytes from iTunesDB")
+
+        write_hashab(itdb_data, firewire_id)
+        print("HASHAB computed successfully!")
+
+    except Exception as e:
+        print(f"Error: {e}")
+        sys.exit(1)

src/vendor/iTunesDB_Writer/mhip_writer.py

@@ -0,0 +1,138 @@
+"""MHIP Writer — Write playlist item chunks for iTunesDB.
+
+MHIP chunks are playlist entries that reference tracks by their ID.
+Each playlist (MHYP) contains MHIP entries for each track in the playlist.
+
+The binary layout of the header is defined declaratively in
+``iTunesDB_Shared.field_defs.MHIP_FIELDS``.
+
+Cross-referenced against:
+  - iTunesDB_Shared/field_defs.py (single source of truth for offsets)
+  - iTunesDB_Parser/mhip_parser.py parse_playlistItem()
+  - libgpod itdb_itunesdb.c: mk_mhip(), write_podcast_mhips()
+"""
+
+import struct
+
+from iTunesDB_Shared.field_base import write_fields, write_generic_header
+from iTunesDB_Shared.mhip_defs import MHIP_HEADER_SIZE
+from iTunesDB_Shared.mhod_defs import (
+    MHOD_HEADER_SIZE as _MHOD_HEADER_SIZE,
+    MHOD100_POSITION_BODY_SIZE,
+    write_mhod_header,
+)
+from iTunesDB_Shared.constants import MHOD_TYPE_TITLE
+
+
+def write_mhip(
+    track_id: int,
+    position: int = 0,
+    mhip_id: int = 0,
+    timestamp: int = 0,
+    podcast_group_flag: int = 0,
+    podcast_group_ref: int = 0,
+    track_persistent_id: int = 0,
+    mhip_persistent_id: int = 0,
+) -> bytes:
+    """
+    Write an MHIP (playlist item) chunk.
+
+    MHIP entries link tracks to playlists by referencing the track ID.
+    Each entry also includes an MHOD type 100 with the position.
+
+    Args:
+        track_id: The track's ID (from MHIT)
+        position: Position in playlist (0-based)
+        mhip_id: Unique ID for this MHIP entry (written at offset 0x14)
+                 In libgpod this is called "podcastgroupid" but it's used
+                 for ALL playlists as a unique entry identifier.
+        timestamp: Mac timestamp (usually 0)
+        podcast_group_flag: For podcast grouping (usually 0)
+        podcast_group_ref: For podcast grouping (usually 0)
+        track_persistent_id: The track's db_track_id (persistent identifier)
+        mhip_persistent_id: Per-track persistent ID for this playlist item
+
+    Returns:
+        Complete MHIP chunk bytes
+    """
+    mhod_position = write_mhod_position(position)
+    total_length = MHIP_HEADER_SIZE + len(mhod_position)
+
+    header = bytearray(MHIP_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhip', MHIP_HEADER_SIZE, total_length)
+    write_fields(header, 0, 'mhip', {
+        'child_count': 1,
+        'podcast_group_flag': podcast_group_flag,
+        'group_id': mhip_id,
+        'track_id': track_id,
+        'timestamp': timestamp,
+        'group_id_ref': podcast_group_ref,
+        'track_persistent_id': track_persistent_id,
+        'mhip_persistent_id': mhip_persistent_id,
+    }, MHIP_HEADER_SIZE)
+
+    return bytes(header) + mhod_position
+
+
+def write_mhod_position(position: int) -> bytes:
+    """
+    Write an MHOD type 100 (playlist position).
+
+    This MHOD is attached to each MHIP and indicates the track's
+    position within the playlist.
+
+    Args:
+        position: Track position in playlist (0-based)
+
+    Returns:
+        MHOD chunk bytes
+    """
+    total_len = _MHOD_HEADER_SIZE + MHOD100_POSITION_BODY_SIZE
+    header = write_mhod_header(100, total_len)
+
+    # Data section: position(4) + padding(16)
+    data = struct.pack('<I', position) + (b'\x00' * 16)
+
+    return header + data
+
+
+def write_mhip_podcast_group(album_name: str, group_id: int) -> bytes:
+    """Write a podcast group header MHIP.
+
+    In the type 3 (podcast) MHSD dataset, episodes are grouped under
+    their podcast show.  Each show gets a "group header" MHIP that
+    serves as a parent node.  Child episode MHIPs reference it via
+    ``group_id_ref``.
+
+    Group header MHIPs differ from regular MHIPs:
+      - ``podcast_group_flag`` = 256 (0x100)
+      - ``track_id`` = 0 (no track reference)
+      - Contains an MHOD type 1 (title) with the album/show name
+        instead of an MHOD type 100 (position)
+
+    This matches libgpod's ``write_one_podcast_group()`` in
+    ``itdb_itunesdb.c``.
+
+    Args:
+        album_name: Podcast show / album name for the group header
+        group_id:   Unique identifier for this group (child MHIPs
+                    reference this value in their ``group_id_ref`` field)
+
+    Returns:
+        Complete MHIP chunk bytes (header + MHOD title)
+    """
+    from .mhod_writer import write_mhod_string
+
+    mhod_title = write_mhod_string(MHOD_TYPE_TITLE, album_name)
+    total_length = MHIP_HEADER_SIZE + len(mhod_title)
+
+    header = bytearray(MHIP_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhip', MHIP_HEADER_SIZE, total_length)
+    write_fields(header, 0, 'mhip', {
+        'child_count': 1,
+        'podcast_group_flag': 256,  # 0x100 = podcast group header
+        'group_id': group_id,
+        'track_id': 0,             # group headers don't reference a track
+    }, MHIP_HEADER_SIZE)
+
+    return bytes(header) + mhod_title

src/vendor/iTunesDB_Writer/mhit_writer.py

@@ -0,0 +1,394 @@
+"""
+MHIT Writer — Write track item chunks for iTunesDB.
+
+MHIT chunks contain all metadata for a single track, plus child MHOD
+chunks for strings (title, artist, path, etc.).
+
+The binary layout of the header is defined declaratively in
+``iTunesDB_Shared.field_defs.MHIT_FIELDS``.  This writer builds a
+values dict and delegates serialization to ``write_fields()``,
+guaranteeing that field offsets / sizes / transforms stay in sync
+with the parser.
+
+Cross-referenced against:
+  - iTunesDB_Shared/field_defs.py (single source of truth for offsets)
+  - iTunesDB_Parser/mhit_parser.py parse_trackItem()
+  - libgpod itdb_itunesdb.c: mk_mhit()
+  - iPodLinux wiki MHIT documentation
+"""
+
+import random
+import time
+from dataclasses import dataclass
+
+from iTunesDB_Shared.constants import (
+    AUDIO_FORMAT_FLAG_DEFAULT,
+    AUDIO_FORMAT_FLAG_MAP,
+    FILETYPE_CODES,
+    MEDIA_TYPE_AUDIO,
+    MEDIA_TYPE_MUSIC_VIDEO,
+    MEDIA_TYPE_PODCAST,
+    MEDIA_TYPE_TV_SHOW,
+    MEDIA_TYPE_VIDEO,
+    MEDIA_TYPE_VIDEO_PODCAST,
+)
+from iTunesDB_Shared.field_base import write_fields, write_generic_header
+from iTunesDB_Shared.mhit_defs import MHIT_HEADER_SIZE, mhit_header_size_for_version
+
+from .mhod_writer import write_track_mhods
+
+
+def generate_db_track_id() -> int:
+    """Generate a random 64-bit persistent ID for a track."""
+    return random.getrandbits(64)
+
+
+generate_db_id = generate_db_track_id
+
+
+@dataclass
+class TrackInfo:
+    """Track metadata for writing to iTunesDB."""
+
+    # Required
+    title: str
+    location: str  # iPod path like ":iPod_Control:Music:F00:ABCD.mp3"
+
+    # File info
+    size: int = 0  # File size in bytes
+    length: int = 0  # Duration in milliseconds
+    filetype: str = 'mp3'  # mp3, m4a, m4p, etc.
+    bitrate: int = 0  # kbps
+    sample_rate: int = 44100  # Hz
+    vbr: bool = False
+
+    # Metadata
+    artist: str | None = None
+    album: str | None = None
+    album_artist: str | None = None
+    genre: str | None = None
+    composer: str | None = None
+    comment: str | None = None
+    year: int = 0
+    track_number: int = 0
+    total_tracks: int = 0
+    disc_number: int = 1
+    total_discs: int = 1
+    bpm: int = 0
+    compilation_flag: bool = False
+
+    # Playback
+    rating: int = 0  # 0-100 (stars × 20)
+    play_count: int = 0
+    skip_count: int = 0
+    volume: int = 0  # -255 to +255
+    start_time: int = 0  # ms
+    stop_time: int = 0  # ms
+    sound_check: int = 0  # Volume normalization value (from ReplayGain)
+    bookmark_time: int = 0  # Resume position in ms (audiobooks/podcasts)
+    checked_flag: int = 0  # 0 = checked/enabled, 1 = unchecked/disabled
+
+    # Gapless playback
+    gapless_data: int = 0  # Gapless playback encoder delay data
+    gapless_track_flag: int = 0  # 1 = track has gapless info
+    gapless_album_flag: int = 0  # 1 = album is gapless
+    pregap: int = 0  # Encoder pregap samples
+    postgap: int = 0  # Encoder postgap/padding samples (0xC8)
+    sample_count: int = 0  # Total decoded sample count (64-bit)
+    encoder_flag: int = 0  # 0xCC: 0x01=MP3 encoder, 0x00=other
+
+    # Track flags
+    skip_when_shuffling: bool = False  # 1 = skip in shuffle mode
+    remember_position: bool = False    # 1 = resume from bookmark (audiobooks)
+    podcast_flag: int = 0  # 0xA7: 0x00=normal, 0x01/0x02=podcast
+    movie_file_flag: int = 0  # 0xB1: 0x01=video/movie file, 0x00=audio
+    played_mark: int = -1  # 0xB2: -1=auto (derive from play_count), 0x01=played, 0x02=unplayed
+    explicit_flag: int = 0  # 0=none, 1=explicit, 2=clean
+    purchased_aac_flag: int = 0  # 0x93: 1 for M4A/iTunes purchases, 0 for most MP3s
+    has_lyrics: bool = False  # True if track has embedded lyrics
+    lyrics: str | None = None  # Full lyrics text (MHOD type 10)
+    eq_setting: str | None = None  # EQ preset name (MHOD type 7), e.g. "Bass Booster"
+
+    # Timestamps (Unix)
+    date_added: int = 0  # Will be set to now if 0
+    date_released: int = 0
+    last_modified: int = 0  # 0x20: file modification time (0 = use date_added)
+    last_played: int = 0
+    last_skipped: int = 0
+
+    # iPod-specific
+    track_id: int = 0  # Will be assigned during write
+    db_track_id: int = 0  # Will be generated if 0
+    media_type: int = MEDIA_TYPE_AUDIO
+    season_number: int = 0  # 0xD4: TV show season number
+    episode_number: int = 0  # 0xD8: TV show episode number
+    artwork_count: int = 0
+    artwork_size: int = 0
+    mhii_link: int = 0  # Link to ArtworkDB
+    album_id: int = 0  # Links to MHIA album entry
+    source_path: str | None = None  # PC source path; internal write-time helper context
+    source_relative_path: str | None = None  # PC path relative to library root, if known
+
+    # Sorting
+    sort_artist: str | None = None
+    sort_name: str | None = None
+    sort_album: str | None = None
+    sort_album_artist: str | None = None
+    sort_composer: str | None = None
+
+    # Extra string metadata
+    grouping: str | None = None
+    keywords: str | None = None  # MHOD type 24 (track keywords)
+
+    # Podcast string metadata (written as MHODs)
+    podcast_enclosure_url: str | None = None  # MHOD type 15
+    podcast_rss_url: str | None = None        # MHOD type 16
+    category: str | None = None               # MHOD type 9
+
+    # Video string metadata (written as MHODs)
+    description: str | None = None       # MHOD type 14
+    subtitle: str | None = None          # MHOD type 18
+    show_name: str | None = None         # MHOD type 19 (TV show name)
+    episode_id: str | None = None        # MHOD type 20 (e.g. "S01E05")
+    network_name: str | None = None      # MHOD type 21 (TV network)
+    sort_show: str | None = None         # MHOD type 31
+    show_locale: str | None = None       # MHOD type 25 (show locale, e.g. "en_US")
+
+    # Filetype description
+    filetype_desc: str | None = None  # e.g., "MPEG audio file"
+
+    # Round-trip fields (preserved from existing iPod database)
+    user_id: int = 0      # 0x64: DRM user ID (preserved for round-trip)
+    app_rating: int = 0   # 0x79: Application-computed rating (preserved for round-trip)
+    mpeg_audio_type: int = 0  # 0x90: MPEG Audio Object Type (12=MP3, 51=AAC, 41=Audible)
+
+    # iTunes Store metadata (round-trip, only for Store purchases)
+    date_added_to_itunes: int = 0    # 0xDC: Unix ts, original iTunes library add date
+    store_track_id: int = 0          # 0xE0: iTunes Store per-track content ID
+    store_encoder_version: int = 0   # 0xE4: iTunes version that encoded the file
+    store_artist_id: int = 0         # 0xE8: iTunes Store artist/collection ID
+    store_album_id: int = 0          # 0xF0: iTunes Store album ID
+    store_content_flag: int = 0      # 0xF4: iTunes Store content type flag
+
+    # Internal IDs (assigned during database write, NOT user-provided)
+    artist_id: int = 0   # Links to artist entry (assigned by writer)
+    composer_id: int = 0  # Links to composer entry (assigned by writer)
+
+    # Chapter data (MHOD type 17) lives in iTunesDB, independent of filetype.
+    chapter_data: dict | None = None
+
+    # Internal sync hint (transient, not written to database)
+    # Used by ArtworkDB writer to determine preservation strategy:
+    # "preserve_existing" = use existing art without re-encoding
+    # "clear_art" = remove art for this track
+    # "" (empty) = normal processing
+    _iop_artwork_sync_hint: str = ""
+
+    @property
+    def db_id(self) -> int:
+        """Backward-compatible alias for the track persistent ID."""
+        return self.db_track_id
+
+    @db_id.setter
+    def db_id(self, value: int) -> None:
+        self.db_track_id = value
+
+
+def _compute_sort_indicators(track: TrackInfo) -> bytes:
+    """Build the 8-byte sort_mhod_indicators field from sort field presence.
+
+    Byte layout (verified via exhaustive bit-correlation across 9 databases):
+      [0] = sort_title (MHOD 27)
+      [1] = sort_album (MHOD 28)
+      [2] = sort_artist (MHOD 23)
+      [3] = sort_album_artist (MHOD 29)
+      [4] = sort_composer (MHOD 30)
+      [5] = sort_show (MHOD 31)
+      [6..7] = unused (always 0)
+
+    bit 0 = has corresponding sort MHOD override
+    bit 7 = collation flag (0x80), always set for compatibility
+    """
+    ind = bytearray(8)
+    ind[0] = 0x81 if track.sort_name else 0x80
+    ind[1] = 0x81 if track.sort_album else 0x80
+    ind[2] = 0x81 if track.sort_artist else 0x80
+    ind[3] = 0x81 if track.sort_album_artist else 0x80
+    ind[4] = 0x81 if track.sort_composer else 0x80
+    ind[5] = 0x81 if track.sort_show else 0x80
+    return bytes(ind)
+
+
+def _resolve_media_type(track: TrackInfo, capabilities) -> int:
+    """Downgrade media type when the device lacks required capability."""
+    media_type = track.media_type
+    if capabilities is None:
+        return media_type
+    if not capabilities.supports_video:
+        if media_type in (MEDIA_TYPE_VIDEO, MEDIA_TYPE_MUSIC_VIDEO, MEDIA_TYPE_TV_SHOW):
+            return MEDIA_TYPE_AUDIO
+        if media_type == MEDIA_TYPE_VIDEO_PODCAST:
+            return MEDIA_TYPE_PODCAST
+    if not capabilities.supports_podcast:
+        if media_type in (MEDIA_TYPE_PODCAST, MEDIA_TYPE_VIDEO_PODCAST):
+            return MEDIA_TYPE_AUDIO
+    return media_type
+
+
+def _resolve_movie_flag(track: TrackInfo, media_type: int) -> int:
+    """Derive movie_flag from media_type when not explicitly set."""
+    if track.movie_file_flag != 0:
+        return track.movie_file_flag
+    if media_type in (MEDIA_TYPE_VIDEO, MEDIA_TYPE_MUSIC_VIDEO,
+                      MEDIA_TYPE_TV_SHOW, MEDIA_TYPE_VIDEO_PODCAST):
+        return 1
+    return 0
+
+
+def _resolve_not_played(track: TrackInfo) -> int:
+    """Resolve the not_played_flag: auto-derive from play_count when -1."""
+    if track.played_mark >= 0:
+        return track.played_mark
+    return 0x01 if track.play_count > 0 else 0x02
+
+
+def _gapless_or_zero(value: int, capabilities) -> int:
+    """Return *value* when the device supports gapless, else 0."""
+    if capabilities is not None and not capabilities.supports_gapless:
+        return 0
+    return value
+
+
+def write_mhit(track: TrackInfo, track_id: int, db_id_2: int = 0,
+               capabilities=None, db_version: int = 0) -> bytes:
+    """Write a complete MHIT chunk with all child MHODs.
+
+    Args:
+        track: TrackInfo dataclass with all track metadata.
+        track_id: Unique track ID within this database.
+        db_id_2: Database-wide ID from MHBD offset 0x24 (written into every track).
+        capabilities: Optional DeviceCapabilities for gapless/video filtering.
+        db_version: Database version — controls the MHIT header size.
+                    Older iPods require smaller headers (e.g. 0x148 for db_version ≤ 0x19).
+
+    Returns:
+        Complete MHIT chunk bytes (header + MHODs).
+    """
+    if track.db_track_id == 0:
+        track.db_track_id = generate_db_track_id()
+    if track.date_added == 0:
+        track.date_added = int(time.time())
+
+    ft = track.filetype.lower()
+    filetype_code = FILETYPE_CODES.get(ft, FILETYPE_CODES['mp3'])
+    media_type = _resolve_media_type(track, capabilities)
+    has_lyrics = track.has_lyrics or bool(track.lyrics)
+
+    # Build child MHODs first to know count + size.
+    mhod_data, mhod_count = write_track_mhods(
+        title=track.title, location=track.location,
+        artist=track.artist, album=track.album, genre=track.genre,
+        album_artist=track.album_artist, composer=track.composer,
+        comment=track.comment, filetype_desc=track.filetype_desc,
+        sort_artist=track.sort_artist, sort_name=track.sort_name,
+        sort_album=track.sort_album, sort_album_artist=track.sort_album_artist,
+        sort_composer=track.sort_composer, grouping=track.grouping,
+        keywords=track.keywords, description=track.description,
+        subtitle=track.subtitle, show_name=track.show_name,
+        episode_id=track.episode_id, network_name=track.network_name,
+        sort_show=track.sort_show, show_locale=track.show_locale,
+        podcast_enclosure_url=track.podcast_enclosure_url,
+        podcast_rss_url=track.podcast_rss_url, category=track.category,
+        lyrics=track.lyrics, eq_setting=track.eq_setting,
+        chapter_data=track.chapter_data,
+    )
+
+    # Use device-appropriate header size.  Older iPod firmware expects smaller
+    # MHIT headers; fields beyond the header boundary are automatically skipped
+    # by write_fields() via each field's min_header_length attribute.
+    header_size = mhit_header_size_for_version(db_version) if db_version else MHIT_HEADER_SIZE
+    total_length = header_size + len(mhod_data)
+
+    # Assemble the values dict — write_fields handles transforms & packing.
+    values: dict = {
+        'child_count': mhod_count,
+        'track_id': track_id,
+        'visible': 1,
+        'filetype': filetype_code,
+        'vbr_flag': 1 if track.vbr else 0,
+        'mp3_flag': 1 if ft == 'mp3' else 0,
+        'compilation_flag': 1 if track.compilation_flag else 0,
+        'rating': track.rating,
+        'last_modified': track.last_modified or track.date_added,
+        'size': track.size,
+        'length': track.length,
+        'track_number': track.track_number,
+        'total_tracks': track.total_tracks,
+        'year': track.year,
+        'bitrate': track.bitrate,
+        'sample_rate_1': track.sample_rate,
+        'volume': track.volume,
+        'start_time': track.start_time,
+        'stop_time': track.stop_time,
+        'sound_check': track.sound_check,
+        'play_count_1': track.play_count,
+        'play_count_2': 0,  # reset after sync
+        'last_played': track.last_played,
+        'disc_number': track.disc_number,
+        'total_discs': track.total_discs,
+        'user_id': track.user_id,
+        'date_added': track.date_added,
+        'bookmark_time': track.bookmark_time,
+        'db_track_id': track.db_track_id,
+        'checked_flag': track.checked_flag,
+        'app_rating': track.app_rating,
+        'bpm': max(0, track.bpm) if track.bpm is not None else 0,
+        'artwork_count': track.artwork_count,
+        'audio_format_flag': AUDIO_FORMAT_FLAG_MAP.get(ft, AUDIO_FORMAT_FLAG_DEFAULT),
+        'artwork_size': track.artwork_size,
+        'sample_rate_2': float(track.sample_rate),
+        'date_released': track.date_released,
+        'mpeg_audio_type': track.mpeg_audio_type,
+        'explicit_flag': track.explicit_flag,
+        'purchased_aac_flag': track.purchased_aac_flag,
+        # Extended fields
+        'skip_count': track.skip_count,
+        'last_skipped': track.last_skipped,
+        'has_artwork': 1 if track.artwork_count > 0 else 2,
+        'skip_when_shuffling': 1 if track.skip_when_shuffling else 0,
+        'remember_position': 1 if track.remember_position else 0,
+        'use_podcast_now_playing_flag': track.podcast_flag,
+        'db_track_id_2': track.db_track_id,
+        'lyrics_flag': 1 if has_lyrics else 0,
+        'movie_flag': _resolve_movie_flag(track, media_type),
+        'not_played_flag': _resolve_not_played(track),
+        'pregap': _gapless_or_zero(track.pregap, capabilities),
+        'sample_count': _gapless_or_zero(track.sample_count, capabilities),
+        'postgap': _gapless_or_zero(track.postgap, capabilities),
+        'encoder': track.encoder_flag,
+        'media_type': media_type,
+        'season_number': track.season_number,
+        'episode_number': track.episode_number,
+        'date_added_to_itunes': track.date_added_to_itunes,
+        'store_track_id': track.store_track_id,
+        'store_encoder_version': track.store_encoder_version,
+        'store_artist_id': track.store_artist_id,
+        'store_album_id': track.store_album_id,
+        'store_content_flag': track.store_content_flag,
+        'gapless_audio_payload_size': _gapless_or_zero(track.gapless_data, capabilities),
+        'gapless_track_flag': _gapless_or_zero(track.gapless_track_flag, capabilities),
+        'gapless_album_flag': _gapless_or_zero(track.gapless_album_flag, capabilities),
+        'album_id': track.album_id,
+        'db_id_2_ref': db_id_2,
+        'size_2': track.size,
+        'sort_mhod_indicators': _compute_sort_indicators(track),
+        'artwork_id_ref': track.mhii_link,
+        'artist_id_ref': track.artist_id,
+        'composer_id': track.composer_id,
+    }
+
+    header = bytearray(header_size)
+    write_generic_header(header, 0, b'mhit', header_size, total_length)
+    write_fields(header, 0, 'mhit', values, header_size)
+
+    return bytes(header) + mhod_data

src/vendor/iTunesDB_Writer/mhla_writer.py

@@ -0,0 +1,199 @@
+"""MHLA Writer — Write album list chunks for iTunesDB.
+
+MHLA (album list) contains MHIA (album item) entries that group tracks.
+Introduced in iTunes 7.1 (dbversion >= 0x14).
+
+MHLA header layout (MHLA_HEADER_SIZE = 92 bytes):
+    +0x00: 'mhla' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: album_count (4B)
+
+MHIA header layout (MHIA_HEADER_SIZE = 88 bytes):
+    +0x00: 'mhia' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: total_length (4B) — header + child MHODs
+    +0x0C: child_count (4B)
+    +0x10: album_id (4B) — links to MHIT.albumID
+    +0x14: sql_id (8B) — internal iPod DB id (must be non-zero)
+    +0x1C: platform_flag (2B, always 2) + album_compilation_flag (2B, 0=normal, 1=compilation)
+
+    Children: MHOD types 200 (album name), 201 (artist), 202 (sort artist)
+
+Cross-referenced against:
+  - iTunesDB_Parser/mhia_parser.py parse_albumItem()
+  - libgpod itdb_itunesdb.c: mk_mhia()
+"""
+
+import random
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from .mhit_writer import TrackInfo
+
+from iTunesDB_Shared.album_identity import (
+    album_identity_from_track,
+    group_tracks_by_album_identity,
+)
+from iTunesDB_Shared.constants import (
+    MHOD_TYPE_ALBUM_ALBUM,
+    MHOD_TYPE_ALBUM_ARTIST_ITEM,
+    MHOD_TYPE_ALBUM_PODCAST_URL,
+    MHOD_TYPE_ALBUM_SHOW,
+    MHOD_TYPE_ALBUM_SORT_ARTIST,
+)
+from iTunesDB_Shared.field_base import (
+    MHLA_HEADER_SIZE,
+    write_fields,
+    write_generic_header,
+)
+from iTunesDB_Shared.mhia_defs import MHIA_HEADER_SIZE
+
+from .mhod_writer import write_mhod_string
+
+
+def write_mhia(album_id: int, album_name: str, album_artist: str,
+               sort_album_artist: str = "",
+               podcast_url: str = "", show_name: str = "",
+               is_compilation: bool = False,
+               album_track_db_id: int = 0) -> bytes:
+    """
+    Write an MHIA (album item) chunk.
+
+    Args:
+        album_id: Unique album ID (used to link tracks to albums)
+        album_name: Album name
+        album_artist: Album artist
+        sort_album_artist: Sort album artist (for proper alphabetical sorting)
+        podcast_url: Podcast RSS URL (MHOD type 203)
+        show_name: Show/series name (MHOD type 204)
+        is_compilation: True for Various Artists / compilation albums
+        album_track_db_id: db_track_id of a representative track in this album
+
+    Returns:
+        Complete MHIA chunk with MHODs
+    """
+    # Build child MHODs
+    children = bytearray()
+    child_count = 0
+
+    if album_name:
+        children.extend(write_mhod_string(MHOD_TYPE_ALBUM_ALBUM, album_name))
+        child_count += 1
+
+    if album_artist:
+        children.extend(write_mhod_string(MHOD_TYPE_ALBUM_ARTIST_ITEM, album_artist))
+        child_count += 1
+
+    if sort_album_artist:
+        children.extend(write_mhod_string(MHOD_TYPE_ALBUM_SORT_ARTIST, sort_album_artist))
+        child_count += 1
+
+    if podcast_url:
+        children.extend(write_mhod_string(MHOD_TYPE_ALBUM_PODCAST_URL, podcast_url))
+        child_count += 1
+
+    if show_name:
+        children.extend(write_mhod_string(MHOD_TYPE_ALBUM_SHOW, show_name))
+        child_count += 1
+
+    # Total chunk length
+    total_length = MHIA_HEADER_SIZE + len(children)
+
+    # Build header
+    header = bytearray(MHIA_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhia', MHIA_HEADER_SIZE, total_length)
+
+    # CRITICAL: sql_id must be non-zero! Clean iTunes DBs have random u64 values here.
+    sql_id = random.getrandbits(64)
+    write_fields(header, 0, 'mhia', {
+        'child_count': child_count,
+        'album_id': album_id,
+        'sql_id': sql_id,
+        'platform_flag': 2,
+        'album_compilation_flag': 1 if is_compilation else 0,
+        'album_track_db_id': album_track_db_id,
+    }, MHIA_HEADER_SIZE)
+
+    return bytes(header) + bytes(children)
+
+
+def _pick_first(tracks: list["TrackInfo"], attr: str) -> str:
+    for track in tracks:
+        value = getattr(track, attr, None) or ""
+        if value:
+            return value
+    return ""
+
+
+def write_mhla(
+    tracks: list["TrackInfo"],
+    starting_index_for_album_id,
+) -> tuple[bytes, dict[tuple[str, str], int], int]:
+    """
+    Write an MHLA (album list) chunk with albums derived from tracks.
+
+    Args:
+        tracks: List of TrackInfo objects
+
+    Returns:
+        Tuple of (MHLA chunk bytes, album_map dict mapping (album, artist) to album_id)
+    """
+    groups = group_tracks_by_album_identity(tracks, album_identity_from_track)
+
+    # Build album items
+    album_items = bytearray()
+    album_map: dict[tuple[str, str], int] = {}  # (album, artist) -> album_id
+
+    def _album_sort_key(group):
+        identity = group.identity
+        album_name = identity.album or ""
+        album_artist = identity.album_artist or identity.artist or ""
+        show_name = identity.show_name or ""
+        return (album_name, album_artist, show_name)
+
+    album_id = starting_index_for_album_id
+    for group in sorted(groups, key=_album_sort_key):
+        identity = group.identity
+        album_name = identity.album or ""
+        album_artist = identity.album_artist or identity.artist or ""
+        album_map[(album_name, album_artist)] = album_id
+        # Use sort_albumartist from track first, fall back to sort_artist (per libgpod mk_mhia)
+        sort_artist = _pick_first(group.tracks, "sort_album_artist")
+        if not sort_artist:
+            sort_artist = _pick_first(group.tracks, "sort_artist")
+        podcast_url = _pick_first(group.tracks, "podcast_rss_url")
+        show_name = identity.show_name or _pick_first(group.tracks, "show_name")
+        # Album is a compilation if any track in it has compilation_flag=True
+        is_compilation = any(t.compilation_flag for t in group.tracks)
+        # Use first track's db_track_id as the representative track for this album
+        rep_db_track_id = group.tracks[0].db_track_id if group.tracks else 0
+        for track in group.tracks:
+            track.album_id = album_id
+        album_items.extend(write_mhia(
+            album_id, album_name, album_artist, sort_artist,
+            podcast_url=podcast_url, show_name=show_name,
+            is_compilation=is_compilation,
+            album_track_db_id=rep_db_track_id,
+        ))
+        album_id += 1
+
+    album_count = len(album_map)
+
+    # Build header
+    header = bytearray(MHLA_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhla', MHLA_HEADER_SIZE, album_count)
+
+    return bytes(header) + bytes(album_items), album_map, album_id
+
+
+def write_mhla_empty() -> bytes:
+    """
+    Write an empty MHLA (album list) chunk.
+
+    Returns:
+        MHLA header with 0 albums
+    """
+    header = bytearray(MHLA_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhla', MHLA_HEADER_SIZE, 0)
+
+    return bytes(header)

src/vendor/iTunesDB_Writer/mhli_writer.py

@@ -0,0 +1,136 @@
+"""MHLI Writer — Write artist list chunks for iTunesDB.
+
+MHSD type 8 contains an artist list using 'mhli' as the list header and
+'mhii' as individual artist items.  Despite sharing the 'mhii' magic with
+ArtworkDB image items, these are structurally different chunks.
+
+MHLI header layout (MHLI_HEADER_SIZE = 92 bytes):
+    +0x00: 'mhli' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: artist_count (4B)
+
+MHII header layout (MHII_HEADER_SIZE = 80 bytes, per libgpod mk_mhii):
+    +0x00: 'mhii' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: total_length (4B) — header + child MHODs
+    +0x0C: child_count (4B) — always 1 (the artist-name MHOD)
+    +0x10: artist_id (4B) — links to MHIT.artist_id
+    +0x14: sql_id (8B) — internal iPod DB id (must be non-zero)
+    +0x1C: platform_flag (4B) — always 2
+
+    Children: MHOD type 300 (artist name / album-artist name)
+
+Cross-referenced against:
+  - libgpod itdb_itunesdb.c: mk_mhii() (artist variant)
+  - docs/iTunesCDB-internals.md §Type 8
+"""
+
+import random
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from .mhit_writer import TrackInfo
+
+from iTunesDB_Shared.field_base import (
+    MHLI_HEADER_SIZE,
+    write_fields,
+    write_generic_header,
+)
+from iTunesDB_Shared.mhii_defs import MHII_HEADER_SIZE
+from iTunesDB_Shared.constants import MHOD_TYPE_ARTIST_NAME
+from .mhod_writer import write_mhod_string
+
+
+def write_mhii_artist(artist_id: int, artist_name: str) -> bytes:
+    """
+    Write an MHII (artist item) chunk for the artist list.
+
+    Args:
+        artist_id: Unique artist ID (used to link tracks to artists)
+        artist_name: Artist name string
+
+    Returns:
+        Complete MHII chunk with MHOD type 300
+    """
+    # Build child MHOD (always exactly 1: the artist name)
+    children = bytearray()
+    child_count = 0
+
+    if artist_name:
+        children.extend(write_mhod_string(MHOD_TYPE_ARTIST_NAME, artist_name))
+        child_count += 1
+
+    # Total chunk length
+    total_length = MHII_HEADER_SIZE + len(children)
+
+    # Build header
+    header = bytearray(MHII_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhii', MHII_HEADER_SIZE, total_length)
+
+    # CRITICAL: sql_id must be non-zero! Clean iTunes DBs have random u64 values here.
+    sql_id = random.getrandbits(64)
+    write_fields(header, 0, 'mhii', {
+        'child_count': child_count,
+        'artist_id': artist_id,
+        'sql_id': sql_id,
+        'platform_flag': 2,
+    }, MHII_HEADER_SIZE)
+
+    return bytes(header) + bytes(children)
+
+
+def write_mhli(tracks: list["TrackInfo"], starting_index_for_artist_id: int) -> tuple[bytes, dict[str, int], int]:
+    """
+    Write an MHLI (artist list) chunk with artists derived from tracks.
+
+    Deduplicates artists using case-insensitive matching (same as album
+    deduplication in mhla_writer.py).
+
+    Args:
+        tracks: List of TrackInfo objects
+
+    Returns:
+        Tuple of (MHLI chunk bytes, artist_map dict mapping artist_name_lower to artist_id)
+    """
+    # Collect unique artists: lowercase artist name → display name
+    # Use the first occurrence's casing as the canonical display name
+    artist_display: dict[str, str] = {}
+    for track in tracks:
+        artist_name = track.artist or ""
+        if not artist_name:
+            continue
+        key = artist_name.lower()
+        if key not in artist_display:
+            artist_display[key] = artist_name
+
+    # Build artist items
+    artist_items = bytearray()
+    artist_map: dict[str, int] = {}  # lowercase artist → artist_id
+
+    artist_id = starting_index_for_artist_id
+    for key in sorted(artist_display.keys()):
+        display_name = artist_display[key]
+        artist_map[key] = artist_id
+        artist_items.extend(write_mhii_artist(artist_id, display_name))
+        artist_id += 1
+
+    artist_count = len(artist_map)
+
+    # Build header
+    header = bytearray(MHLI_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhli', MHLI_HEADER_SIZE, artist_count)
+
+    return bytes(header) + bytes(artist_items), artist_map, artist_id
+
+
+def write_mhli_empty() -> bytes:
+    """
+    Write an empty MHLI (artist list) chunk.
+
+    Returns:
+        MHLI header with 0 artists
+    """
+    header = bytearray(MHLI_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhli', MHLI_HEADER_SIZE, 0)
+
+    return bytes(header)

src/vendor/iTunesDB_Writer/mhlp_writer.py

@@ -0,0 +1,238 @@
+"""MHLP Writer — Write playlist list chunks for iTunesDB.
+
+MHLP (playlist list) wraps all MHYP (playlist) chunks and provides
+the playlist count in its header. Every iTunesDB needs at least a
+"master playlist" referencing all tracks.
+
+Header layout (MHLP_HEADER_SIZE = 92 bytes):
+    +0x00: 'mhlp' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: playlist_count (4B)
+
+Supports:
+- Master + user playlists (write_mhlp_with_playlists)
+- Dataset 3 podcast playlists (podcast clone of dataset 2)
+- Dataset 5 smart playlists (write_mhlp_smart)
+
+Cross-referenced against:
+  - iTunesDB_Parser/mhlp_parser.py
+  - libgpod itdb_itunesdb.c: mk_mhlp()
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import List, Optional, TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from .mhit_writer import TrackInfo
+    from .mhyp_writer import PlaylistInfo
+
+from iTunesDB_Shared.field_base import MHLP_HEADER_SIZE, write_generic_header
+from .mhyp_writer import write_master_playlist, write_playlist
+
+logger = logging.getLogger(__name__)
+
+
+def write_mhlp_empty() -> bytes:
+    """
+    Write an empty MHLP (playlist list) chunk.
+
+    Note: An empty MHLP means NO playlists, which may cause issues
+    on some iPods. Use write_mhlp_with_playlists() for a valid database.
+
+    Returns:
+        MHLP header with 0 playlists
+    """
+    header = bytearray(MHLP_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhlp', MHLP_HEADER_SIZE, 0)
+
+    return bytes(header)
+
+
+def write_mhlp(playlist_chunks: List[bytes]) -> bytes:
+    """
+    Write a MHLP chunk with playlists.
+
+    Args:
+        playlist_chunks: List of MHYP (playlist) chunks
+
+    Returns:
+        Complete MHLP chunk
+    """
+    # Concatenate all playlist data
+    playlists_data = b''.join(playlist_chunks)
+
+    header = bytearray(MHLP_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhlp', MHLP_HEADER_SIZE, len(playlist_chunks))
+
+    return bytes(header) + playlists_data
+
+
+def write_mhlp_with_playlists(
+    track_ids: List[int],
+    playlists: List[PlaylistInfo],
+    db_id_2,
+    tracks: Optional[List[TrackInfo]] = None,
+    capabilities=None,
+    master_playlist_name: str = "iPod",
+    master_playlist_id: Optional[int] = None,
+) -> bytes:
+    """
+    Write an MHLP chunk with the master playlist + user playlists.
+
+    The master playlist is always first, followed by regular/smart playlists.
+    This is used for MHSD type 2 (playlists dataset).
+
+    The master playlist is auto-generated from the full track list; its
+    display name is controlled by *master_playlist_name*.  The *playlists*
+    list should contain only user playlists (no master).
+
+    Args:
+        track_ids: List of ALL track IDs in the database (for master playlist)
+        playlists: List of user PlaylistInfo objects (master is NOT included)
+        tracks: List of ALL TrackInfo objects (needed for library indices)
+        db_id_2: Database-wide ID from MHBD offset 0x24
+        capabilities: Optional DeviceCapabilities for video sort indices.
+        master_playlist_name: Display name for the auto-generated master playlist.
+
+    Returns:
+        Complete MHLP chunk
+    """
+    chunks = []
+
+    # Master playlist MUST be first
+    master = write_master_playlist(
+        track_ids, tracks=tracks, db_id_2=db_id_2,
+        capabilities=capabilities, name=master_playlist_name,
+        playlist_id=master_playlist_id,
+    )
+    chunks.append(master)
+
+    # Sanity: strip rogue master flags from dataset-2 user playlists.
+    # Only the auto-generated master above should have master=True.
+    # Dataset 5 built-in categories (mhsd5_type != 0) legitimately
+    # need master=True, so we never touch those — even if they end up
+    # here by accident.
+    for p in playlists:
+        if p.master and not p.mhsd5_type:
+            logger.warning(
+                "Stripped master flag from user playlist '%s' — "
+                "master is auto-generated for dataset 2",
+                p.name,
+            )
+            p.master = False
+
+    # Write all user playlists (regular and smart).
+    for pl in playlists:
+        chunks.append(write_playlist(pl, db_id_2=db_id_2))
+
+    return write_mhlp(chunks)
+
+
+def write_mhlp_with_playlists_type3(
+    track_ids: List[int],
+    playlists: List["PlaylistInfo"],
+    db_id_2: int,
+    track_album_map: dict[int, str],
+    tracks: Optional[List["TrackInfo"]] = None,
+    capabilities=None,
+    master_playlist_name: str = "iPod",
+    next_mhip_id_start: int = 1,
+    master_playlist_id: Optional[int] = None,
+) -> bytes:
+    """Write an MHLP for MHSD type 3 with podcast grouping.
+
+    Identical to :func:`write_mhlp_with_playlists` **except** that playlist
+    entries marked as podcast (``podcast_flag == 1``) use the grouped
+    MHIP structure described by libgpod's ``write_podcast_mhips()``.
+
+    In the grouped structure, podcast episodes are nested under their
+    podcast show (album).  Each show gets a group-header MHIP
+    (``podcast_group_flag=256``, MHOD title = album name) followed by
+    child episode MHIPs whose ``group_id_ref`` points back to the header.
+
+    Non-podcast playlists are written with the standard flat MHIP layout,
+    identical to type 2.
+
+    Args:
+        track_ids: ALL track IDs in the database (for the master playlist)
+        playlists: User playlist list (same objects as type 2; master is
+                   auto-generated)
+        db_id_2: Database-wide ID from MHBD offset 0x24
+        track_album_map: track_id → album name for podcast grouping
+        tracks: TrackInfo list (needed for master playlist library indices)
+        capabilities: DeviceCapabilities (for video sort indices etc.)
+        master_playlist_name: Display name for the master playlist.
+        next_mhip_id_start: Starting ID for generated MHIP identifiers.
+
+    Returns:
+        Complete MHLP chunk bytes.
+    """
+    chunks = []
+
+    # Master playlist — identical to type 2
+    master = write_master_playlist(
+        track_ids, tracks=tracks, db_id_2=db_id_2,
+        capabilities=capabilities, name=master_playlist_name,
+        playlist_id=master_playlist_id,
+    )
+    chunks.append(master)
+
+    for p in playlists:
+        if p.master and not p.mhsd5_type:
+            logger.warning(
+                "Stripped master flag from user playlist '%s' — "
+                "master is auto-generated for dataset 3",
+                p.name,
+            )
+            p.master = False
+
+    for pl in playlists:
+        chunks.append(write_playlist(
+            pl, db_id_2=db_id_2,
+            podcast_grouping=True,
+            track_album_map=track_album_map,
+            next_mhip_id_start=next_mhip_id_start,
+        ))
+
+    return write_mhlp(chunks)
+
+
+def write_mhlp_smart(
+    playlists: List[PlaylistInfo],
+    db_id_2: int = 0,
+) -> bytes:
+    """
+    Write an MHLP chunk for dataset type 5 (smart playlist list).
+
+    These playlists define iPod built-in browse categories (Music, Movies,
+    TV Shows, Audiobooks, Podcasts, Rentals). Each has a mhsd5_type value
+    and smart rules that filter by media type.
+
+    **Master flag semantics for dataset 5:**
+    All built-in categories legitimately have ``master=True`` which writes
+    ``type=1`` at MHYP offset +0x14.  This is the SAME byte used by the
+    master playlist in dataset 2, but the meaning differs:
+
+    - Dataset 2 ``type=1``: "this is the master playlist" (exactly one)
+    - Dataset 5 ``type=1``: "this is a built-in system category" (all of them)
+
+    No single-master constraint is enforced here — every ds5 category
+    needs ``master=True`` for the iPod firmware to recognise it.
+
+    Args:
+        playlists: List of PlaylistInfo objects (smart playlists only)
+        db_id_2: Database-wide ID from MHBD offset 0x24
+
+    Returns:
+        Complete MHLP chunk, or empty MHLP if no smart playlists
+    """
+    if not playlists:
+        return write_mhlp_empty()
+
+    chunks = []
+    for pl in playlists:
+        chunks.append(write_playlist(pl, db_id_2=db_id_2))
+
+    return write_mhlp(chunks)

src/vendor/iTunesDB_Writer/mhlt_writer.py

@@ -0,0 +1,59 @@
+"""MHLT Writer — Write track list chunks for iTunesDB.
+
+MHLT (track list) wraps all MHIT (track) chunks and provides
+the track count in its header.
+
+Header layout (MHLT_HEADER_SIZE = 92 bytes):
+    +0x00: 'mhlt' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: track_count (4B)
+
+Cross-referenced against:
+  - iTunesDB_Parser/mhlt_parser.py
+  - libgpod itdb_itunesdb.c: mk_mhlt()
+"""
+
+from typing import List
+
+from iTunesDB_Shared.field_base import MHLT_HEADER_SIZE, write_generic_header
+from .mhit_writer import write_mhit, TrackInfo
+
+
+def write_mhlt(tracks: List[TrackInfo], start_track_id: int, db_id_2: int,
+               capabilities=None, db_version: int = 0) -> tuple[bytes, int]:
+    """
+    Write a complete MHLT chunk with all tracks.
+
+    Args:
+        tracks: List of TrackInfo objects
+        start_track_id: Starting track ID (increments for each track)
+        db_id_2: Database-wide ID from MHBD (written into every MHIT db_id_2_ref at offset 0x124)
+        capabilities: Optional DeviceCapabilities for gapless/video filtering
+        db_version: Database version — forwarded to write_mhit for header sizing
+
+    Returns:
+        Tuple of (complete MHLT chunk bytes, next available track ID)
+    """
+
+    # Build all track chunks first
+    track_chunks = []
+    track_id = start_track_id
+
+    for track in tracks:
+        try:
+            mhit_data = write_mhit(track, track_id, db_id_2, capabilities=capabilities,
+                                   db_version=db_version)
+        except Exception as exc:
+            raise type(exc)(
+                f"{exc} (track #{track_id}: {track.artist!r} – {track.title!r})"
+            ) from exc
+        track_chunks.append(mhit_data)
+        track_id += 1
+
+    # Concatenate all track data
+    all_tracks_data = b''.join(track_chunks)
+
+    header = bytearray(MHLT_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhlt', MHLT_HEADER_SIZE, len(tracks))
+
+    return bytes(header) + all_tracks_data, track_id

src/vendor/iTunesDB_Writer/mhod52_writer.py

@@ -0,0 +1,334 @@
+"""
+MHOD Type 52/53 Writer - Library Playlist Index for iTunesDB.
+
+These MHODs are written ONLY for the Master Playlist and provide
+pre-sorted track indices that the iPod uses to build its browsing
+views (Songs, Artists, Albums, Genres, Composers).
+
+Without these indices, the iPod Classic shows "no songs, no albums"
+even if tracks exist in the database.
+
+Based on libgpod's mk_mhod52(), mk_mhod53(), and write_playlist()
+in itdb_itunesdb.c.
+
+Type 52 (MHOD_ID_LIBPLAYLISTINDEX):
+  Pre-sorted track position arrays for each sort category.
+  Format: header(24) + sort_type(4) + count(4) + padding(40) + indices(count*4)
+  Total = 4*count + 72
+
+Type 53 (MHOD_ID_LIBPLAYLISTJUMPTABLE):
+  Letter-jump table for quick scrolling in each category.
+  Format: header(24) + sort_type(4) + count(4) + padding(8) + entries(count*12)
+  Total = 12*count + 40
+"""
+
+import struct
+import unicodedata
+from typing import TYPE_CHECKING
+
+from iTunesDB_Shared.field_base import strip_article
+from iTunesDB_Shared.mhod_defs import (
+    MHOD52_BODY_HEADER_SIZE,
+    MHOD53_BODY_HEADER_SIZE,
+    MHOD53_ENTRY_SIZE,
+    MHOD_HEADER_SIZE,
+    SORT_ALBUM,
+    SORT_ALBUM_ARTIST,
+    SORT_ARTIST,
+    SORT_COMPOSER,
+    SORT_EPISODE,
+    SORT_GENRE,
+    SORT_SEASON,
+    SORT_SHOW,
+    SORT_TITLE,
+    write_mhod_header,
+)
+
+if TYPE_CHECKING:
+    from .mhit_writer import TrackInfo
+
+# Base sort types — always written
+BASE_SORT_TYPES = [SORT_TITLE, SORT_ALBUM, SORT_ARTIST, SORT_GENRE, SORT_COMPOSER]
+
+# Video sort types — only for devices with supports_video
+VIDEO_SORT_TYPES = [SORT_SHOW, SORT_SEASON, SORT_EPISODE]
+
+# Legacy alias for backward compatibility
+ALL_SORT_TYPES = BASE_SORT_TYPES
+
+
+def _sort_key(s: str) -> str:
+    """
+    Create a case-insensitive sort key for a string.
+
+    Strips leading articles (A, An, The) for sorting (matching iTunes behavior),
+    normalizes unicode, and lowercases.
+    """
+    if not s:
+        return ""
+    s = strip_article(s)
+    # Normalize unicode for consistent comparison
+    return unicodedata.normalize('NFKD', s).casefold()
+
+
+def _jump_table_letter(s: str) -> int:
+    """
+    Get the first alphanumeric character for jump table grouping.
+
+    Returns uppercase letter (A-Z) as Unicode codepoint, or ord('0')
+    for strings starting with digits.
+
+    Based on libgpod's jump_table_letter().
+    """
+    if not s:
+        return ord('0')
+
+    for ch in s:
+        if ch.isalnum():
+            if ch.isdigit():
+                return ord('0')
+            upper = ord(ch.upper()[0])
+            if upper > 0xFFFF:
+                continue  # non-BMP char can't fit in UTF-16 jump table
+            return upper
+
+    return ord('0')
+
+
+def _get_sort_fields(track: "TrackInfo", sort_type: int) -> tuple:
+    """
+    Get sort key fields for a track based on sort type.
+
+    Returns a tuple used for sorting. Multi-field sorts match
+    libgpod's mhod52_sort_* comparison functions.
+
+    IMPORTANT: For every field, prefer the sort_* variant over the
+    display variant (e.g. sort_album over album).  This matches
+    libgpod's ``sort_compare(track->sort_X ? track->sort_X : track->X, ...)``
+    pattern used in mhod52_sort_album(), mhod52_sort_artist(), etc.
+    """
+    title = _sort_key(track.sort_name or track.title or "")
+    album = _sort_key(track.sort_album or track.album or "")
+    artist = _sort_key(track.sort_artist or track.artist or "")
+    genre = _sort_key(track.genre or "")
+    composer = _sort_key(track.sort_composer or track.composer or "")
+    track_nr = track.track_number or 0
+    cd_nr = track.disc_number or 0
+
+    if sort_type == SORT_TITLE:
+        return (title,)
+    elif sort_type == SORT_ALBUM:
+        return (album, cd_nr, track_nr, title)
+    elif sort_type == SORT_ARTIST:
+        return (artist, album, cd_nr, track_nr, title)
+    elif sort_type == SORT_GENRE:
+        return (genre, artist, album, cd_nr, track_nr, title)
+    elif sort_type == SORT_COMPOSER:
+        return (composer, album, cd_nr, track_nr, title)
+    elif sort_type == SORT_SHOW:
+        show = _sort_key(track.sort_show or track.show_name or "")
+        season = track.season_number or 0
+        episode = track.episode_number or 0
+        return (show, season, episode, title)
+    elif sort_type == SORT_SEASON:
+        season = track.season_number or 0
+        episode = track.episode_number or 0
+        show = _sort_key(track.sort_show or track.show_name or "")
+        return (season, episode, show, title)
+    elif sort_type == SORT_EPISODE:
+        episode = track.episode_number or 0
+        season = track.season_number or 0
+        show = _sort_key(track.sort_show or track.show_name or "")
+        return (episode, season, show, title)
+    elif sort_type == SORT_ALBUM_ARTIST:
+        album_artist = _sort_key(
+            track.sort_album_artist
+            or track.album_artist
+            or track.sort_artist or track.artist or ""
+        )
+        return (album_artist, album, cd_nr, track_nr, title)
+    else:
+        return (title,)
+
+
+def _get_jump_letter(track: "TrackInfo", sort_type: int) -> int:
+    """Get the letter for jump table grouping based on sort type.
+
+    Uses sort_* field variants for consistency with ``_get_sort_fields``.
+    """
+    if sort_type == SORT_TITLE:
+        return _jump_table_letter(track.sort_name or track.title or "")
+    elif sort_type == SORT_ALBUM:
+        return _jump_table_letter(track.sort_album or track.album or "")
+    elif sort_type == SORT_ARTIST:
+        s = track.sort_artist or track.artist or ""
+        return _jump_table_letter(s)
+    elif sort_type == SORT_GENRE:
+        return _jump_table_letter(track.genre or "")
+    elif sort_type == SORT_COMPOSER:
+        return _jump_table_letter(track.sort_composer or track.composer or "")
+    elif sort_type == SORT_SHOW:
+        return _jump_table_letter(track.sort_show or track.show_name or "")
+    elif sort_type == SORT_SEASON:
+        n = track.season_number or 0
+        return _jump_table_letter(str(n)) if n else ord('0')
+    elif sort_type == SORT_EPISODE:
+        n = track.episode_number or 0
+        return _jump_table_letter(str(n)) if n else ord('0')
+    elif sort_type == SORT_ALBUM_ARTIST:
+        s = (
+            track.sort_album_artist
+            or track.album_artist
+            or track.sort_artist or track.artist or ""
+        )
+        return _jump_table_letter(s)
+    else:
+        return _jump_table_letter(track.sort_name or track.title or "")
+
+
+def write_mhod_type52(tracks: list["TrackInfo"], sort_type: int) -> tuple[bytes, list[tuple[int, int, int]]]:
+    """
+    Write a Type 52 MHOD (library playlist index) for one sort category.
+
+    Args:
+        tracks: List of all TrackInfo objects (in original order)
+        sort_type: Sort category (SORT_TITLE, SORT_ALBUM, etc.)
+
+    Returns:
+        Tuple of (MHOD bytes, jump_table_entries) where jump_table_entries
+        is a list of (letter, start, count) tuples for the corresponding
+        Type 53 MHOD.
+    """
+    num_tracks = len(tracks)
+
+    # Create indexed list: (sort_key, original_index, track)
+    indexed = []
+    for i, track in enumerate(tracks):
+        sort_key = _get_sort_fields(track, sort_type)
+        indexed.append((sort_key, i, track))
+
+    # Sort by the sort key
+    indexed.sort(key=lambda x: x[0])
+
+    # Build sorted track indices (original position in track list)
+    sorted_indices = [idx for _, idx, _ in indexed]
+
+    # Build jump table entries: group by first letter
+    jump_entries: list[tuple[int, int, int]] = []
+    last_letter = -1
+    current_entry = None
+
+    for pos, (_, _, track) in enumerate(indexed):
+        letter = _get_jump_letter(track, sort_type)
+        if letter != last_letter:
+            current_entry = (letter, pos, 0)
+            jump_entries.append(current_entry)
+            last_letter = letter
+        # Increment count for current entry
+        letter_val, start, count = jump_entries[-1]
+        jump_entries[-1] = (letter_val, start, count + 1)
+
+    # Build MHOD type 52 binary data
+    # Body: sort_type(4) + count(4) + padding(40) + indices(count*4)
+    total_len = 4 * num_tracks + MHOD_HEADER_SIZE + MHOD52_BODY_HEADER_SIZE
+
+    header = write_mhod_header(52, total_len)
+
+    # Body header
+    body_header = bytearray(MHOD52_BODY_HEADER_SIZE)
+    struct.pack_into('<I', body_header, 0, sort_type)    # sort type
+    struct.pack_into('<I', body_header, 4, num_tracks)   # number of entries
+    # Remaining 40 bytes are zero padding
+
+    # Track indices
+    indices_data = bytearray(4 * num_tracks)
+    for i, idx in enumerate(sorted_indices):
+        struct.pack_into('<I', indices_data, i * 4, idx)
+
+    return bytes(header) + bytes(body_header) + bytes(indices_data), jump_entries
+
+
+def write_mhod_type53(sort_type: int, jump_entries: list[tuple[int, int, int]]) -> bytes:
+    """
+    Write a Type 53 MHOD (library playlist jump table) for one sort category.
+
+    Args:
+        sort_type: Sort category (must match corresponding type 52)
+        jump_entries: List of (letter, start, count) tuples from write_mhod_type52()
+
+    Returns:
+        Complete MHOD type 53 bytes
+    """
+    num_entries = len(jump_entries)
+
+    # Build MHOD type 53 binary data
+    # Body: sort_type(4) + count(4) + padding(8) + entries(count*12)
+    total_len = MHOD53_ENTRY_SIZE * num_entries + MHOD_HEADER_SIZE + MHOD53_BODY_HEADER_SIZE
+
+    header = write_mhod_header(53, total_len)
+
+    # Body header
+    body_header = bytearray(MHOD53_BODY_HEADER_SIZE)
+    struct.pack_into('<I', body_header, 0, sort_type)     # sort type
+    struct.pack_into('<I', body_header, 4, num_entries)    # number of entries
+    # 8 bytes zero padding
+
+    # Jump table entries: each is letter(u16) + pad(u16) + start(u32) + count(u32)
+    entries_data = bytearray(MHOD53_ENTRY_SIZE * num_entries)
+    for i, (letter, start, count) in enumerate(jump_entries):
+        offset = i * MHOD53_ENTRY_SIZE
+        struct.pack_into('<H', entries_data, offset, letter)       # letter (UTF-16)
+        struct.pack_into('<H', entries_data, offset + 2, 0)        # padding
+        struct.pack_into('<I', entries_data, offset + 4, start)    # start index
+        struct.pack_into('<I', entries_data, offset + 8, count)    # count
+
+    return bytes(header) + bytes(body_header) + bytes(entries_data)
+
+
+def write_library_indices(tracks: list["TrackInfo"], capabilities=None) -> tuple[bytes, int]:
+    """
+    Write all library index MHODs (type 52 + type 53 pairs) for the
+    master playlist.
+
+    Base sort categories (always written):
+    - Title (0x03), Album (0x04), Artist (0x05), Genre (0x07), Composer (0x12)
+
+    Video sort categories (when capabilities.supports_video is True):
+    - Show (0x1D), Season (0x1E), Episode (0x1F)
+
+    Album Artist sort (0x23) is written for all devices with capabilities
+    (i.e. modern iPods that use the capabilities system).
+
+    Args:
+        tracks: List of all TrackInfo objects
+        capabilities: Optional DeviceCapabilities for conditional sort types.
+
+    Returns:
+        Tuple of (concatenated MHOD bytes, count of MHODs written)
+    """
+    if not tracks:
+        return b'', 0
+
+    # Build the list of sort types to write
+    sort_types = list(BASE_SORT_TYPES)
+    if capabilities is not None:
+        if capabilities.supports_video:
+            sort_types.extend(VIDEO_SORT_TYPES)
+        # Album artist sort for all modern iPods
+        sort_types.append(SORT_ALBUM_ARTIST)
+
+    result = bytearray()
+    mhod_count = 0
+
+    for sort_type in sort_types:
+        # Write type 52 (sorted index)
+        mhod52_data, jump_entries = write_mhod_type52(tracks, sort_type)
+        result.extend(mhod52_data)
+        mhod_count += 1
+
+        # Write type 53 (jump table)
+        mhod53_data = write_mhod_type53(sort_type, jump_entries)
+        result.extend(mhod53_data)
+        mhod_count += 1
+
+    return bytes(result), mhod_count

src/vendor/iTunesDB_Writer/mhod_spl_writer.py

@@ -0,0 +1,329 @@
+"""
+MHOD Type 50/51 Writer — Smart Playlist Preferences & Rules.
+
+Type 50 (SPLPref): Controls live-update, checked-only, and limit settings.
+Type 51 (SPLRules/SLst): The actual filter rules that define the smart playlist.
+
+The SLst blob is the ONLY part of the iTunesDB that uses big-endian encoding.
+All multi-byte integers within SLst must be written as big-endian, and
+string values use UTF-16 BE (not LE like the rest of the database).
+
+Based on libgpod's SPLPref/SPLRules structs in itdb_spl.c / itdb_itunesdb.c
+and the parser in iTunesDB_Parser/mhod_parser.py.
+"""
+
+import struct
+from dataclasses import dataclass, field
+
+from iTunesDB_Shared.mhod_defs import (
+    MHOD_HEADER_SIZE,
+    SLST_HEADER_SIZE,
+    SPL_RULE_DATA_SIZE,
+    SPL_RULE_HEADER_SIZE,
+    SPLFT_DATE,
+    SPLFT_STRING,
+    SPLPREF_BODY_SIZE,
+    spl_get_field_type,
+    write_mhod_header,
+)
+
+DATE_RELATIVE_ACTION_IDS = {0x00000200, 0x02000200}
+
+
+# ────────────────────────────────────────────────────────────
+# Data classes
+# ────────────────────────────────────────────────────────────
+
+@dataclass
+class SmartPlaylistPrefs:
+    """Smart playlist preferences (MHOD type 50 / SPLPref).
+
+    Mirrors the fields parsed by _parse_mhod50_smart_playlist_data().
+    """
+    live_update: bool = True
+    check_rules: bool = True
+    check_limits: bool = False
+    limit_type: int = 0x03       # 1=minutes, 2=MB, 3=songs, 4=hours, 5=GB
+    limit_sort: int = 0x02       # 2=random (low byte); high bit 0x80000000 = reverse
+    limit_value: int = 25
+    match_checked_only: bool = False
+
+
+@dataclass
+class SmartPlaylistRule:
+    """A single smart playlist rule (one entry inside SLst).
+
+    field_id and action_id use the raw integer codes from the parser
+    constants (SPL_FIELD_MAP, SPL_ACTION_MAP).
+    """
+    field_id: int = 0x02         # e.g. 0x02=Song Name, 0x3C=Media Type
+    action_id: int = 0x01000002  # e.g. 0x01000002 = "contains"
+
+    # For STRING rules
+    string_value: str | None = None
+
+    # For non-string rules (INT/DATE/BOOLEAN/PLAYLIST/BINARY_AND)
+    from_value: int = 0
+    from_date: int = 0
+    from_units: int = 0
+    to_value: int = 0
+    to_date: int = 0
+    to_units: int = 0
+
+    # Five unknown trailing 32-bit values (preserved for round-trip)
+    unk052: int = 0
+    unk056: int = 0
+    unk060: int = 0
+    unk064: int = 0
+    unk068: int = 0
+
+
+@dataclass
+class SmartPlaylistRules:
+    """Full smart playlist rules container (MHOD type 51 / SLst).
+
+    conjunction: "AND" (match all) or "OR" (match any)
+    """
+    conjunction: str = "AND"  # "AND" or "OR"
+    rules: list[SmartPlaylistRule] = field(default_factory=list)
+    unk004: int = 0  # SLst header +0x04, usually 0 (preserved for round-trip)
+
+
+def _signed_i64(value: int) -> int:
+    value = int(value or 0)
+    if value >= (1 << 63):
+        return value - (1 << 64)
+    return value
+
+
+def _normalize_relative_date_fields(
+    from_value: int,
+    from_date: int,
+    from_units: int = 0,
+) -> tuple[int, int]:
+    signed_from_value = _signed_i64(from_value)
+    normalized_from_date = int(from_date or 0)
+    if normalized_from_date:
+        normalized_from_date = -abs(normalized_from_date)
+    elif signed_from_value:
+        amount = abs(signed_from_value)
+        units = int(from_units or 0)
+        if units > 1 and amount >= units and amount % units == 0:
+            normalized_from_date = -(amount // units)
+        else:
+            normalized_from_date = -amount
+    return 0, normalized_from_date
+
+
+# ────────────────────────────────────────────────────────────
+# MHOD Type 50 — Smart Playlist Preferences
+# ────────────────────────────────────────────────────────────
+
+def write_mhod50(prefs: SmartPlaylistPrefs) -> bytes:
+    """Write MHOD type 50 (smart playlist preferences / SPLPref).
+
+    Returns:
+        Complete MHOD chunk bytes.
+    """
+    body = bytearray(SPLPREF_BODY_SIZE)
+
+    body[0] = 1 if prefs.live_update else 0
+    body[1] = 1 if prefs.check_rules else 0
+    body[2] = 1 if prefs.check_limits else 0
+    body[3] = prefs.limit_type & 0xFF
+
+    # limit_sort: low byte at +4, reverse flag at +13
+    low_byte = prefs.limit_sort & 0xFF
+    reverse = 1 if (prefs.limit_sort & 0x80000000) else 0
+    body[4] = low_byte
+
+    # 3 bytes padding (5..7) already zero
+
+    struct.pack_into('<I', body, 8, prefs.limit_value)
+
+    body[12] = 1 if prefs.match_checked_only else 0
+    body[13] = reverse
+
+    # Remaining bytes (14..131) are zero padding
+
+    return write_mhod_header(50, MHOD_HEADER_SIZE + SPLPREF_BODY_SIZE) + bytes(body)
+
+
+# ────────────────────────────────────────────────────────────
+# MHOD Type 51 — Smart Playlist Rules (SLst)
+# ────────────────────────────────────────────────────────────
+
+def _write_spl_rule(rule: SmartPlaylistRule) -> bytes:
+    """Write a single SLst rule entry (big-endian).
+
+    Rule layout:
+        +0x00: field     (4 BE)
+        +0x04: action    (4 BE)
+        +0x08: padding   (44 bytes)
+        +0x34: length    (4 BE) — byte length of data
+        +0x38: data      (length bytes)
+
+    Total = SPL_RULE_HEADER_SIZE + data_length.
+    """
+    ft = spl_get_field_type(rule.field_id)
+
+    if ft == SPLFT_STRING and rule.string_value is not None:
+        # String rule: data = UTF-16 BE string
+        string_bytes = rule.string_value.encode('utf-16-be')
+        data_length = len(string_bytes)
+        data_section = string_bytes
+    else:
+        # Non-string: fixed SPL_RULE_DATA_SIZE (68) byte data section
+        data_length = SPL_RULE_DATA_SIZE
+        data_section = bytearray(SPL_RULE_DATA_SIZE)
+        from_value = rule.from_value
+        from_date = rule.from_date
+        if ft == SPLFT_DATE and rule.action_id in DATE_RELATIVE_ACTION_IDS:
+            from_value, from_date = _normalize_relative_date_fields(
+                from_value,
+                from_date,
+                rule.from_units,
+            )
+        # from_value, to_value, from_units, to_units use unsigned '>Q' format.
+        # Mask defensively so legacy in-memory rules with signed values still pack.
+        _mask = 0xFFFFFFFFFFFFFFFF
+        struct.pack_into('>Q', data_section, 0x00, from_value & _mask)
+        struct.pack_into('>q', data_section, 0x08, from_date)
+        struct.pack_into('>Q', data_section, 0x10, rule.from_units & _mask)
+        struct.pack_into('>Q', data_section, 0x18, rule.to_value & _mask)
+        struct.pack_into('>q', data_section, 0x20, rule.to_date)
+        struct.pack_into('>Q', data_section, 0x28, rule.to_units & _mask)
+        struct.pack_into('>I', data_section, 0x30, rule.unk052)
+        struct.pack_into('>I', data_section, 0x34, rule.unk056)
+        struct.pack_into('>I', data_section, 0x38, rule.unk060)
+        struct.pack_into('>I', data_section, 0x3C, rule.unk064)
+        struct.pack_into('>I', data_section, 0x40, rule.unk068)
+        data_section = bytes(data_section)
+
+    # Build rule header
+    rule_header = bytearray(SPL_RULE_HEADER_SIZE)
+    struct.pack_into('>I', rule_header, 0x00, rule.field_id)
+    struct.pack_into('>I', rule_header, 0x04, rule.action_id)
+    # 44 bytes padding (0x08..0x33) already zero
+    struct.pack_into('>I', rule_header, 0x34, data_length)
+
+    return bytes(rule_header) + data_section
+
+
+def write_mhod51(rules_data: SmartPlaylistRules) -> bytes:
+    """Write MHOD type 51 (smart playlist rules / SLst).
+
+    The entire SLst blob is big-endian.
+
+    Returns:
+        Complete MHOD chunk bytes.
+    """
+    # Build SLst header
+    slst_header = bytearray(SLST_HEADER_SIZE)
+    slst_header[0:4] = b'SLst'
+    struct.pack_into('>I', slst_header, 4, rules_data.unk004)
+    struct.pack_into('>I', slst_header, 8, len(rules_data.rules))
+    conjunction_val = 1 if rules_data.conjunction.upper() == "OR" else 0
+    struct.pack_into('>I', slst_header, 12, conjunction_val)
+    # 120 bytes padding already zero
+
+    # Build individual rules
+    rules_bytes = b''.join(_write_spl_rule(r) for r in rules_data.rules)
+
+    slst_body = bytes(slst_header) + rules_bytes
+
+    return write_mhod_header(51, MHOD_HEADER_SIZE + len(slst_body)) + slst_body
+
+
+# ────────────────────────────────────────────────────────────
+# MHOD Type 102 — Playlist Settings (opaque blob passthrough)
+# ────────────────────────────────────────────────────────────
+
+def write_mhod102(raw_body: bytes) -> bytes:
+    """Write MHOD type 102 (playlist settings).
+
+    This is an opaque iTunes binary blob. We preserve it verbatim
+    from the parsed data for round-trip fidelity.
+
+    Args:
+        raw_body: The raw body bytes (everything after the 24-byte header).
+
+    Returns:
+        Complete MHOD chunk bytes.
+    """
+    return write_mhod_header(102, MHOD_HEADER_SIZE + len(raw_body)) + raw_body
+
+
+# ────────────────────────────────────────────────────────────
+# Helpers for building from parsed data (round-trip)
+# ────────────────────────────────────────────────────────────
+
+def prefs_from_parsed(parsed: dict) -> SmartPlaylistPrefs:
+    """Create SmartPlaylistPrefs from a parsed MHOD type 50 dict.
+
+    This is the inverse of _parse_mhod50_smart_playlist_data().
+    """
+    # Parser stores limit_sort as the raw low byte and reverse_sort
+    # separately.  Reconstruct the combined value the writer expects.
+    limit_sort = parsed.get("limit_sort", 0x02)
+    if parsed.get("reverse_sort", 0):
+        limit_sort |= 0x80000000
+
+    return SmartPlaylistPrefs(
+        live_update=parsed.get("live_update", True),
+        check_rules=parsed.get("check_rules", True),
+        check_limits=parsed.get("check_limits", False),
+        limit_type=parsed.get("limit_type", 0x03),
+        limit_sort=limit_sort,
+        limit_value=parsed.get("limit_value", 25),
+        match_checked_only=parsed.get("match_checked_only", False),
+    )
+
+
+def rules_from_parsed(parsed: dict) -> SmartPlaylistRules:
+    """Create SmartPlaylistRules from a parsed MHOD type 51 dict.
+
+    This is the inverse of _parse_mhod51_smart_playlist_rules().
+    """
+    rules = []
+    for r in parsed.get("rules", []):
+        field_id = r.get("field_id", 0)
+        action_id = r.get("action_id", 0)
+        from_value = r.get("from_value", 0)
+        from_date = r.get("from_date", 0)
+        from_units = r.get("from_units", 0)
+        if spl_get_field_type(field_id) == SPLFT_DATE and action_id in DATE_RELATIVE_ACTION_IDS:
+            from_value, from_date = _normalize_relative_date_fields(
+                from_value,
+                from_date,
+                from_units,
+            )
+        rule = SmartPlaylistRule(
+            field_id=field_id,
+            action_id=action_id,
+            string_value=r.get("string_value"),
+            from_value=from_value,
+            from_date=from_date,
+            from_units=from_units,
+            to_value=r.get("to_value", 0),
+            to_date=r.get("to_date", 0),
+            to_units=r.get("to_units", 0),
+            unk052=r.get("unk052", 0),
+            unk056=r.get("unk056", 0),
+            unk060=r.get("unk060", 0),
+            unk064=r.get("unk064", 0),
+            unk068=r.get("unk068", 0),
+        )
+        rules.append(rule)
+
+    raw_conj = parsed.get("conjunction", "AND")
+    if isinstance(raw_conj, int):
+        conj = "OR" if raw_conj == 1 else "AND"
+    else:
+        conj = raw_conj
+
+    return SmartPlaylistRules(
+        conjunction=conj,
+        rules=rules,
+        unk004=parsed.get("unk004", 0),
+    )

src/vendor/iTunesDB_Writer/mhod_writer.py

@@ -0,0 +1,434 @@
+"""
+MHOD String Writer — Write string, podcast URL, and chapter data MHOD chunks.
+
+String MHODs (types 1-14, 18-31, 33-44, 200-204, 300) have:
+  - Common MHOD header (24 bytes)
+  - String sub-header (16 bytes): encoding + string_length + unk0x20 + unk0x24
+  - UTF-16LE encoded string data
+
+Podcast URL MHODs (types 15, 16) have:
+  - Common MHOD header (24 bytes)
+  - UTF-8 encoded string directly (NO sub-header)
+
+Chapter Data MHOD (type 17) has:
+  - Common MHOD header (24 bytes)
+  - 12-byte preamble (3 × u32 LE)
+  - Big-endian atom tree: sean → chap × N → name + hedr
+  - Stored in iTunesDB, so it is not tied to an AAC/M4A source file
+
+Cross-referenced against:
+  - iTunesDB_Shared/mhod_defs.py (field definitions and constants)
+  - iTunesDB_Parser/mhod_parser.py _parse_string_mhod(), _parse_chapter_data()
+  - libgpod itdb_itunesdb.c: mk_mhod(), itdb_chapterdata_build_chapter_blob_internal()
+"""
+
+import struct
+
+from iTunesDB_Shared.constants import (
+    MHOD_TYPE_ALBUM,
+    MHOD_TYPE_ALBUM_ARTIST,
+    MHOD_TYPE_ARTIST,
+    MHOD_TYPE_CATEGORY,
+    MHOD_TYPE_CHAPTER_DATA,
+    MHOD_TYPE_COMMENT,
+    MHOD_TYPE_COMPOSER,
+    MHOD_TYPE_DESCRIPTION,
+    MHOD_TYPE_EPISODE_ID,
+    MHOD_TYPE_EQ_SETTING,
+    MHOD_TYPE_FILETYPE,
+    MHOD_TYPE_GENRE,
+    MHOD_TYPE_GROUPING,
+    MHOD_TYPE_KEYWORDS,
+    MHOD_TYPE_LOCATION,
+    MHOD_TYPE_LYRICS,
+    MHOD_TYPE_NETWORK_NAME,
+    MHOD_TYPE_PODCAST_ENCLOSURE_URL,
+    MHOD_TYPE_PODCAST_RSS_URL,
+    MHOD_TYPE_SHOW_LOCALE,
+    MHOD_TYPE_SHOW_NAME,
+    MHOD_TYPE_SORT_ALBUM,
+    MHOD_TYPE_SORT_ALBUM_ARTIST,
+    MHOD_TYPE_SORT_ARTIST,
+    MHOD_TYPE_SORT_COMPOSER,
+    MHOD_TYPE_SORT_NAME,
+    MHOD_TYPE_SORT_SHOW,
+    MHOD_TYPE_SUBTITLE,
+    MHOD_TYPE_TITLE,
+)
+from iTunesDB_Shared.mhod_defs import (
+    CHAP_ATOM,
+    HEDR_ATOM,
+    HEDR_SIZE,
+    MHOD_HEADER_SIZE,
+    MHOD_STRING_SUBHEADER_SIZE,
+    NAME_ATOM,
+    SEAN_ATOM,
+    write_mhod_header,
+)
+
+
+def write_mhod_string(mhod_type: int, value: str,
+                      unk_0x20: int = 1, unk_0x24: int = 0) -> bytes:
+    """
+    Write a string MHOD chunk.
+
+    String MHODs have this structure:
+    - mhod header (24 bytes minimum)
+    - string data type header (16 bytes)
+    - UTF-16LE encoded string
+
+    Args:
+        mhod_type: MHOD type (1=title, 2=location, etc.)
+        value: String value to encode
+        unk_0x20: Sub-header unknown at offset 0x20 (preserved from parser).
+        unk_0x24: Sub-header unknown at offset 0x24 (preserved from parser).
+
+    Returns:
+        Complete MHOD chunk as bytes
+    """
+    if not value:
+        return b''
+
+    string_data = value.encode('utf-16-le')
+    string_len = len(string_data)
+
+    total_len = MHOD_HEADER_SIZE + MHOD_STRING_SUBHEADER_SIZE + string_len
+
+    header = write_mhod_header(mhod_type, total_len)
+
+    # String sub-header: encoding(4) + string_length(4) + unk0x20(4) + unk0x24(4)
+    # encoding=1 means UTF-16LE
+    type_header = struct.pack('<IIII', 1, string_len, unk_0x20, unk_0x24)
+
+    return header + type_header + string_data
+
+
+def write_mhod_location(path: str) -> bytes:
+    """
+    Write a location MHOD (type 2) for file path.
+
+    iPod paths use colons as separators:
+    :iPod_Control:Music:F00:ABCD.mp3
+
+    Args:
+        path: iPod-relative path with colon separators
+
+    Returns:
+        Complete MHOD chunk
+    """
+    return write_mhod_string(MHOD_TYPE_LOCATION, path)
+
+
+def write_mhod_title(title: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_TITLE, title)
+
+
+def write_mhod_artist(artist: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_ARTIST, artist)
+
+
+def write_mhod_album(album: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_ALBUM, album)
+
+
+def write_mhod_genre(genre: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_GENRE, genre)
+
+
+def write_mhod_album_artist(album_artist: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_ALBUM_ARTIST, album_artist)
+
+
+def write_mhod_composer(composer: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_COMPOSER, composer)
+
+
+def write_mhod_comment(comment: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_COMMENT, comment)
+
+
+def write_mhod_filetype(filetype: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_FILETYPE, filetype)
+
+
+def write_mhod_sort_artist(sort_artist: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_SORT_ARTIST, sort_artist)
+
+
+def write_mhod_sort_name(sort_name: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_SORT_NAME, sort_name)
+
+
+def write_mhod_sort_album(sort_album: str) -> bytes:
+    return write_mhod_string(MHOD_TYPE_SORT_ALBUM, sort_album)
+
+
+def write_mhod_podcast_url(mhod_type: int, url: str) -> bytes:
+    """
+    Write a podcast URL MHOD (type 15 or 16).
+
+    Podcast URL MHODs use a DIFFERENT format from standard string MHODs:
+    - UTF-8 encoded (NOT UTF-16LE)
+    - NO type sub-header (string follows directly after the 24-byte header)
+    - Length = total_length − header_length
+
+    Per iPodLinux wiki and parser: types 15 (enclosure URL) and 16 (RSS URL)
+    have no mhod::length field and use UTF-8/ASCII encoding.
+
+    Args:
+        mhod_type: Must be 15 (enclosure URL) or 16 (RSS URL)
+        url: URL string to encode
+
+    Returns:
+        Complete MHOD chunk as bytes
+    """
+    if not url:
+        return b''
+    if mhod_type not in (MHOD_TYPE_PODCAST_ENCLOSURE_URL, MHOD_TYPE_PODCAST_RSS_URL):
+        raise ValueError(f"write_mhod_podcast_url only supports types 15 and 16, got {mhod_type}")
+
+    string_data = url.encode('utf-8')
+    total_len = MHOD_HEADER_SIZE + len(string_data)
+
+    header = write_mhod_header(mhod_type, total_len)
+
+    return header + string_data
+
+
+def write_mhod_chapter_data(
+    chapters: list[dict],
+    unk024: int = 0,
+    unk028: int = 0,
+    unk032: int = 0,
+) -> bytes:
+    """Write a chapter data MHOD (type 17).
+
+    Chapter data uses big-endian atom tree encoding, matching libgpod's
+    ``itdb_chapterdata_build_chapter_blob_internal()``.
+
+    Args:
+        chapters: List of chapter dicts, each with ``startpos`` (int, ms)
+            and ``title`` (str).
+        unk024, unk028, unk032: Preamble unknown fields (preserved from
+            parser, default 0).
+
+    Returns:
+        Complete MHOD type 17 chunk as bytes, or b'' if chapters is empty.
+    """
+    if not chapters:
+        return b''
+
+    # Build the atom tree body (all big-endian).
+    atoms = bytearray()
+
+    for ch in chapters:
+        title = ch.get("title", "")
+        startpos = ch.get("startpos", 0)
+        title_utf16 = title.encode("utf-16-be")
+        title_units = len(title_utf16) // 2
+
+        # name atom: size(4) + "name"(4) + unk=1(4) + unk=0(4) + unk=0(4) + strlen(2) + string
+        name_size = 22 + len(title_utf16)
+        name_atom = struct.pack(">I", name_size)
+        name_atom += NAME_ATOM
+        name_atom += struct.pack(">III", 1, 0, 0)
+        name_atom += struct.pack(">H", title_units)
+        name_atom += title_utf16
+
+        # chap atom: size(4) + "chap"(4) + startpos(4) + children=1(4) + unk=0(4) + name_atom
+        chap_size = 20 + name_size
+        chap_atom = struct.pack(">I", chap_size)
+        chap_atom += CHAP_ATOM
+        chap_atom += struct.pack(">III", startpos, 1, 0)
+        chap_atom += name_atom
+
+        atoms.extend(chap_atom)
+
+    # hedr terminator atom (28 bytes)
+    hedr_atom = struct.pack(">I", HEDR_SIZE)
+    hedr_atom += HEDR_ATOM
+    hedr_atom += struct.pack(">IIIII", 1, 0, 0, 0, 1)
+    atoms.extend(hedr_atom)
+
+    # sean atom header wraps everything
+    num_children = len(chapters) + 1  # chapters + hedr
+    sean_size = 20 + len(atoms)
+    sean_header = struct.pack(">I", sean_size)
+    sean_header += SEAN_ATOM
+    sean_header += struct.pack(">III", 1, num_children, 0)
+
+    # Preamble (little-endian, 12 bytes)
+    preamble = struct.pack("<III", unk024, unk028, unk032)
+
+    # Complete body = preamble + sean_header + atoms
+    body = preamble + sean_header + bytes(atoms)
+
+    # MHOD header + body
+    total_length = MHOD_HEADER_SIZE + len(body)
+    header = write_mhod_header(MHOD_TYPE_CHAPTER_DATA, total_length)
+
+    return header + body
+
+
+def build_chapter_blob(
+    chapters: list[dict],
+    unk024: int = 0,
+    unk028: int = 0,
+    unk032: int = 0,
+) -> bytes:
+    """Build the chapter atom blob (no MHOD header) for SQLite Extras.itdb.
+
+    Same atom tree format as MHOD type 17 but without the 24-byte MHOD header.
+    Used by ``SQLiteDB_Writer.extras_writer`` for the ``chapter.data`` BLOB.
+
+    Returns:
+        Raw chapter blob bytes, or b'' if chapters is empty.
+    """
+    full = write_mhod_chapter_data(chapters, unk024, unk028, unk032)
+    if not full:
+        return b''
+    # Strip the MHOD header to get just the atom tree
+    return full[MHOD_HEADER_SIZE:]
+
+
+def write_track_mhods(
+    title: str,
+    location: str,
+    artist: str | None = None,
+    album: str | None = None,
+    genre: str | None = None,
+    album_artist: str | None = None,
+    composer: str | None = None,
+    comment: str | None = None,
+    filetype_desc: str | None = None,
+    sort_artist: str | None = None,
+    sort_name: str | None = None,
+    sort_album: str | None = None,
+    sort_album_artist: str | None = None,
+    sort_composer: str | None = None,
+    grouping: str | None = None,
+    description: str | None = None,
+    podcast_enclosure_url: str | None = None,
+    podcast_rss_url: str | None = None,
+    subtitle: str | None = None,
+    show_name: str | None = None,
+    episode_id: str | None = None,
+    network_name: str | None = None,
+    keywords: str | None = None,
+    sort_show: str | None = None,
+    category: str | None = None,
+    lyrics: str | None = None,
+    eq_setting: str | None = None,
+    show_locale: str | None = None,
+    chapter_data: dict | None = None,
+) -> tuple[bytes, int]:
+    """
+    Write all MHODs for a track.
+
+    Args:
+        title: Track title (required)
+        location: File path on iPod (required)
+        artist: Artist name
+        album: Album name
+        genre: Genre
+        album_artist: Album artist (for compilations)
+        composer: Composer
+        comment: Comment/notes
+        filetype_desc: File format description (e.g., "MPEG audio file")
+        sort_artist: Sort artist name
+        sort_name: Sort title
+        sort_album: Sort album name
+        sort_album_artist: Sort album artist name
+        sort_composer: Sort composer name
+        grouping: Grouping tag
+        description: Track description (type 14)
+        podcast_enclosure_url: Podcast enclosure URL (type 15, UTF-8, no sub-header)
+        podcast_rss_url: Podcast RSS feed URL (type 16, UTF-8, no sub-header)
+        subtitle: Subtitle (type 18)
+        show_name: TV show name (type 19)
+        episode_id: Episode ID string (type 20)
+        network_name: TV network name (type 21)
+        keywords: Keywords (type 24)
+        sort_show: Sort show name (type 31)
+        category: Podcast/audiobook category (type 9)
+        chapter_data: Chapter data dict with ``chapters`` list (type 17)
+
+    Returns:
+        Tuple of (concatenated MHOD bytes, count of MHODs)
+    """
+    chunks: list[bytes] = []
+
+    # Required MHODs
+    chunks.append(write_mhod_title(title))
+    chunks.append(write_mhod_location(location))
+
+    # Optional string MHODs
+    if artist:
+        chunks.append(write_mhod_artist(artist))
+    if album:
+        chunks.append(write_mhod_album(album))
+    if genre:
+        chunks.append(write_mhod_genre(genre))
+    if album_artist:
+        chunks.append(write_mhod_album_artist(album_artist))
+    if composer:
+        chunks.append(write_mhod_composer(composer))
+    if comment:
+        chunks.append(write_mhod_comment(comment))
+    if filetype_desc:
+        chunks.append(write_mhod_filetype(filetype_desc))
+    if category:
+        chunks.append(write_mhod_string(MHOD_TYPE_CATEGORY, category))
+    if description:
+        chunks.append(write_mhod_string(MHOD_TYPE_DESCRIPTION, description))
+    if subtitle:
+        chunks.append(write_mhod_string(MHOD_TYPE_SUBTITLE, subtitle))
+    if show_name:
+        chunks.append(write_mhod_string(MHOD_TYPE_SHOW_NAME, show_name))
+    if episode_id:
+        chunks.append(write_mhod_string(MHOD_TYPE_EPISODE_ID, episode_id))
+    if network_name:
+        chunks.append(write_mhod_string(MHOD_TYPE_NETWORK_NAME, network_name))
+    if keywords:
+        chunks.append(write_mhod_string(MHOD_TYPE_KEYWORDS, keywords))
+
+    # Sort MHODs
+    if sort_artist:
+        chunks.append(write_mhod_sort_artist(sort_artist))
+    if sort_name:
+        chunks.append(write_mhod_sort_name(sort_name))
+    if sort_album:
+        chunks.append(write_mhod_sort_album(sort_album))
+    if sort_album_artist:
+        chunks.append(write_mhod_string(MHOD_TYPE_SORT_ALBUM_ARTIST, sort_album_artist))
+    if sort_composer:
+        chunks.append(write_mhod_string(MHOD_TYPE_SORT_COMPOSER, sort_composer))
+    if sort_show:
+        chunks.append(write_mhod_string(MHOD_TYPE_SORT_SHOW, sort_show))
+    if show_locale:
+        chunks.append(write_mhod_string(MHOD_TYPE_SHOW_LOCALE, show_locale))
+    if grouping:
+        chunks.append(write_mhod_string(MHOD_TYPE_GROUPING, grouping))
+
+    # Podcast URL MHODs (different format: UTF-8, no sub-header)
+    if podcast_enclosure_url:
+        chunks.append(write_mhod_podcast_url(MHOD_TYPE_PODCAST_ENCLOSURE_URL, podcast_enclosure_url))
+    if podcast_rss_url:
+        chunks.append(write_mhod_podcast_url(MHOD_TYPE_PODCAST_RSS_URL, podcast_rss_url))
+
+    # EQ and lyrics
+    if eq_setting:
+        chunks.append(write_mhod_string(MHOD_TYPE_EQ_SETTING, eq_setting))
+    if lyrics:
+        chunks.append(write_mhod_string(MHOD_TYPE_LYRICS, lyrics))
+
+    # Chapter data (type 17, big-endian atom tree)
+    if chapter_data and chapter_data.get("chapters"):
+        chunks.append(write_mhod_chapter_data(
+            chapters=chapter_data["chapters"],
+            unk024=chapter_data.get("unk024", 0),
+            unk028=chapter_data.get("unk028", 0),
+            unk032=chapter_data.get("unk032", 0),
+        ))
+
+    return b''.join(chunks), len(chunks)

src/vendor/iTunesDB_Writer/mhsd_writer.py

@@ -0,0 +1,101 @@
+"""MHSD Writer — Write dataset chunks for iTunesDB.
+
+MHSD (dataset) chunks are containers for different types of data.
+Each MHSD wraps exactly one child list chunk (mhlt, mhlp, mhla, or mhli).
+
+Header layout (MHSD_HEADER_SIZE = 96 bytes):
+    +0x00: 'mhsd' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: total_length (4B) — header + child data
+    +0x0C: dataset_type (4B):
+           1 = Track list (mhlt)
+           2 = Playlist list (mhlp)
+           3 = Podcast list (mhlp) — same content as type 2
+           4 = Album list (mhla)
+           5 = Smart playlist list (mhlp)
+           6 = Empty stub (mhlt with 0 children)
+           8 = Artist list (mhli with mhii children)
+           10 = Empty stub (mhlt with 0 children)
+
+Cross-referenced against:
+  - iTunesDB_Parser/mhsd_parser.py
+  - libgpod itdb_itunesdb.c: mk_mhsd()
+"""
+
+from iTunesDB_Shared.field_base import (
+    MHLT_HEADER_SIZE,
+    write_fields,
+    write_generic_header,
+)
+from iTunesDB_Shared.mhsd_defs import MHSD_HEADER_SIZE
+
+
+def write_mhsd(dataset_type: int, child_data: bytes) -> bytes:
+    """
+    Write a MHSD (dataset) chunk.
+
+    Args:
+        dataset_type: Type of dataset
+        child_data: Child chunk data (mhlt, mhlp, or mhla)
+
+    Returns:
+        Complete MHSD chunk bytes
+    """
+    # Total length = header + child
+    total_length = MHSD_HEADER_SIZE + len(child_data)
+
+    # Build header
+    header = bytearray(MHSD_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhsd', MHSD_HEADER_SIZE, total_length)
+    write_fields(header, 0, 'mhsd', {'dataset_type': dataset_type}, MHSD_HEADER_SIZE)
+
+    return bytes(header) + child_data
+
+
+def write_mhsd_type1(track_list_data: bytes) -> bytes:
+    """Write a Type 1 MHSD containing track list."""
+    return write_mhsd(1, track_list_data)
+
+
+def write_mhsd_type2(playlist_list_data: bytes) -> bytes:
+    """Write a Type 2 MHSD containing playlist list."""
+    return write_mhsd(2, playlist_list_data)
+
+
+def write_mhsd_type3(podcast_list_data: bytes) -> bytes:
+    """Write a Type 3 MHSD containing podcast list."""
+    return write_mhsd(3, podcast_list_data)
+
+
+def write_mhsd_type4(album_list_data: bytes) -> bytes:
+    """Write a Type 4 MHSD containing album list."""
+    return write_mhsd(4, album_list_data)
+
+
+def write_mhsd_smart_type5(smart_playlist_data: bytes) -> bytes:
+    """Write a Type 5 MHSD containing smart playlist list."""
+    return write_mhsd(5, smart_playlist_data)
+
+
+def write_mhsd_type8(artist_list_data: bytes) -> bytes:
+    """Write a Type 8 MHSD containing artist list (mhli)."""
+    return write_mhsd(8, artist_list_data)
+
+
+def write_mhsd_empty_stub(dataset_type: int) -> bytes:
+    """Write a stub MHSD containing an empty MHLT (0 children).
+
+    Used for types 6 and 10 which libgpod writes as empty track-list
+    stubs.  The child is a minimal MHLT header with count = 0.
+
+    Args:
+        dataset_type: The MHSD type (6 or 10).
+
+    Returns:
+        Complete MHSD + empty MHLT bytes.
+    """
+    # Build an empty MHLT child (92-byte header, 0 tracks)
+    mhlt = bytearray(MHLT_HEADER_SIZE)
+    write_generic_header(mhlt, 0, b'mhlt', MHLT_HEADER_SIZE, 0)
+
+    return write_mhsd(dataset_type, bytes(mhlt))

src/vendor/iTunesDB_Writer/mhyp_writer.py

@@ -0,0 +1,538 @@
+"""
+MHYP Writer — Write playlist chunks for iTunesDB.
+
+MHYP chunks define playlists. Every iTunesDB MUST have at least one
+playlist — the Master Playlist (MPL) which references all tracks.
+
+Supports three kinds of playlists:
+- Master Playlist (master=True): references all tracks, includes library indices
+- Regular playlists: user-created playlists with explicit track lists
+- Smart playlists: rule-based playlists with MHOD types 50 (prefs) and 51 (rules)
+
+Header layout (MHYP_HEADER_SIZE = 184 bytes):
+    +0x00: 'mhyp' magic (4B)
+    +0x04: header_length (4B)
+    +0x08: total_length (4B) — header + all children
+    +0x0C: mhod_count (4B)
+    +0x10: mhip_count (4B)
+    +0x14: type (1B) + flag1 (1B) + flag2 (1B) + flag3 (1B) — master playlist flag
+    +0x18: timestamp (4B Mac)
+    +0x1C: playlist_id (8B)
+    +0x24: unk1 (4B)
+    +0x28: string_mhod_count (2B)
+    +0x2A: podcast_flag (2B) — 0=normal, 1=podcast playlist (u16, libgpod podcastflag)
+    +0x2C: sort_order (4B)
+    +0x3C: db_id_2 (8B) — MHBD database ID reference (non-master)
+    +0x44: playlist_id_copy (8B)
+    +0x50: mhsd5_type (2B) — browsing category for dataset 5
+    +0x58: timestamp_copy (4B Mac)
+
+Cross-referenced against:
+  - iTunesDB_Parser/mhyp_parser.py parse_playlist()
+  - libgpod itdb_itunesdb.c: write_playlist() / mk_mhyp()
+  - iPodLinux wiki MHYP documentation
+"""
+
+import random
+import struct
+import time
+from dataclasses import dataclass, field
+from typing import List, Optional, TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from .mhit_writer import TrackInfo
+
+from iTunesDB_Shared.constants import MHOD_TYPE_TITLE
+from iTunesDB_Shared.field_base import write_fields, write_generic_header
+from iTunesDB_Shared.mhyp_defs import MHYP_HEADER_SIZE
+from iTunesDB_Shared.mhod_defs import (
+    MHOD_HEADER_SIZE as _MHOD_HEADER_SIZE,
+    write_mhod_header,
+)
+from .mhod_writer import write_mhod_string
+from .mhip_writer import write_mhip, write_mhip_podcast_group
+from .mhod52_writer import write_library_indices
+from .mhod_spl_writer import (
+    SmartPlaylistPrefs,
+    SmartPlaylistRules,
+    write_mhod50,
+    write_mhod51,
+    write_mhod102,
+)
+
+
+@dataclass
+class PlaylistItemMeta:
+    """Per-item metadata preserved from parsed MHIP entries for round-trip fidelity.
+
+    These fields map directly to MHIP header offsets:
+      +0x10: podcast_group_flag (4B)
+      +0x14: group_id (4B) — unique MHIP identifier (libgpod: podcastgroupid)
+      +0x20: podcast_group_ref (4B) — references another MHIP's group_id
+      +0x2C: track_persistent_id (8B) — track's db_track_id
+      +0x3C: mhip_persistent_id (8B) — per-track persistent ID
+    """
+    podcast_group_flag: int = 0
+    group_id: int = 0
+    podcast_group_ref: int = 0
+    track_persistent_id: int = 0
+    mhip_persistent_id: int = 0
+
+
+@dataclass
+class PlaylistInfo:
+    """Structured input for writing a playlist to iTunesDB.
+
+    Covers regular playlists, smart playlists, and the master playlist.
+    The master playlist is constructed internally by write_master_playlist()
+    and does not need a PlaylistInfo.
+    """
+    name: str
+    track_ids: List[int] = field(default_factory=list)
+
+    # Identity
+    playlist_id: Optional[int] = None   # 64-bit; generated if None
+    master: bool = False                 # Sets type byte at +0x14 to 1.
+    #   Dataset 2: True for the master playlist only (exactly one).
+    #   Dataset 5: True for ALL built-in categories (Music, Movies, etc.).
+    #   In both cases this controls: (a) the type byte at +0x14,
+    #   (b) whether library indices are generated (only when tracks
+    #       are also provided), and (c) whether db_id_2/playlist_id
+    #       are written at the extended offsets +0x3C/+0x44 (skipped
+    #       when master=True, matching libgpod behaviour).
+    sortorder: int = 0                   # 0=default, 1=manual, 3=title ...
+    podcast_flag: int = 0                # 0x2A: 0=normal, 1=podcast playlist (u16)
+
+    # Smart playlist fields (both must be set for a smart playlist)
+    smart_prefs: Optional[SmartPlaylistPrefs] = None
+    smart_rules: Optional[SmartPlaylistRules] = None
+
+    # mhsd5Type: browsing category for dataset 5 smart playlists
+    # (per libgpod: 0=None, 2=Movies, 3=TV Shows, 4=Music, 5=Audiobooks, 6=Ringtones, 7=MovieRentals)
+    mhsd5_type: int = 0
+
+    # Opaque blobs preserved from parsed data for round-trip fidelity
+    raw_mhod100: Optional[bytes] = None   # Playlist prefs (type 100 body)
+    raw_mhod102: Optional[bytes] = None   # Playlist settings (type 102 body)
+
+    # Per-MHIP metadata preserved from parsed data for round-trip fidelity.
+    # When provided, must be the same length as track_ids and in the same order.
+    item_metadata: Optional[List[PlaylistItemMeta]] = None
+
+    @property
+    def is_smart(self) -> bool:
+        return self.smart_prefs is not None and self.smart_rules is not None
+
+
+def generate_playlist_id() -> int:
+    """Generate a random 64-bit playlist ID."""
+    return random.getrandbits(64)
+
+
+def write_mhyp(
+    name: str,
+    track_ids: List[int],
+    playlist_id: Optional[int] = None,
+    master: bool = False,
+    timestamp: Optional[int] = None,
+    sortorder: int = 0,
+    podcast_flag: int = 0,
+    tracks: Optional[List["TrackInfo"]] = None,
+    db_id_2: int = 0,
+    smart_prefs: Optional[SmartPlaylistPrefs] = None,
+    smart_rules: Optional[SmartPlaylistRules] = None,
+    mhsd5_type: int = 0,
+    raw_mhod100: Optional[bytes] = None,
+    raw_mhod102: Optional[bytes] = None,
+    item_metadata: Optional[List[PlaylistItemMeta]] = None,
+    capabilities=None,
+    podcast_grouping: bool = False,
+    track_album_map: Optional[dict[int, str]] = None,
+    next_mhip_id_start: int = 1,
+) -> bytes:
+    """
+    Write a complete MHYP (playlist) chunk with MHODs and MHIPs.
+
+    The structure is:
+    - MHYP header (184 bytes)
+    - MHOD title (string)
+    - MHOD playlist data (type 100 preferences)
+    - [Smart only] MHOD type 50 (smart playlist prefs)
+    - [Smart only] MHOD type 51 (smart playlist rules / SLst)
+    - [Smart only] MHOD type 102 (playlist settings, if provided)
+    - [Master Playlist only] MHOD type 52/53 pairs (library indices)
+    - MHIP entries (one per track)
+
+    Args:
+        name: Playlist name
+        track_ids: List of track IDs to include in this playlist
+        playlist_id: Playlist ID (generated if not provided)
+        master: Whether the type byte at +0x14 should be set to 1.
+                For dataset 2 this means "master playlist" (exactly one).
+                For dataset 5 this means "built-in system category" (all
+                categories have master=True).  The behavioural effects are:
+                (a) type byte at +0x14 is written as 1,
+                (b) library indices are generated IF *tracks* is also
+                    provided (ds5 never passes tracks, so this is safe),
+                (c) db_id_2 and playlist_id are NOT written at +0x3C/+0x44
+                    (matches libgpod, which zeros these for type=1).
+        timestamp: Creation timestamp (now if not provided)
+        sortorder: Sort order (0 = manual)
+        podcast_flag: 0x2A — 0=normal playlist, 1=podcast playlist (u16,
+                     matching libgpod podcastflag).
+        tracks: List of TrackInfo objects (required for Master Playlist to
+                generate library index MHODs type 52/53)
+        db_id_2: Database-wide ID from MHBD offset 0x24. Written at MHYP offset
+                 0x3C for non-master playlists, and used as a validation field.
+        smart_prefs: Smart playlist preferences (MHOD 50). Both smart_prefs
+                     and smart_rules must be set for a smart playlist.
+        smart_rules: Smart playlist rules (MHOD 51).
+        mhsd5_type: Browsing category for dataset 5 smart playlists.
+        raw_mhod100: If provided, use this raw body for MHOD type 100 instead
+                     of generating a default one.
+        raw_mhod102: If provided, write an MHOD type 102 with this raw body.
+        podcast_grouping: When True and this is a podcast playlist, generate
+                     grouped MHIPs (libgpod write_podcast_mhips style) where
+                     episodes are nested under their podcast show by album.
+        track_album_map: Mapping of track_id → album name.  Required when
+                     podcast_grouping is True.
+        next_mhip_id_start: Starting ID for generated MHIP group_id values
+                     (podcast grouping assigns unique IDs to group headers
+                     and child MHIPs).
+
+    Returns:
+        Complete MHYP chunk bytes
+    """
+    if playlist_id is None:
+        playlist_id = generate_playlist_id()
+
+    if timestamp is None:
+        timestamp = int(time.time())
+
+    # Build MHOD for title
+    mhod_title = write_mhod_string(MHOD_TYPE_TITLE, name)
+
+    # Build MHOD for playlist preferences (type 100)
+    if raw_mhod100 is not None:
+        mhod_playlist = _write_mhod100_raw(raw_mhod100)
+    else:
+        mhod_playlist = write_mhod_playlist_prefs()
+
+    # Smart playlist MHODs (type 50 + 51)
+    mhod_smart = b''
+    smart_mhod_count = 0
+    if smart_prefs is not None and smart_rules is not None:
+        mhod_smart += write_mhod50(smart_prefs)
+        mhod_smart += write_mhod51(smart_rules)
+        smart_mhod_count = 2
+
+    # Optional MHOD type 102 (playlist settings — opaque iTunes blob)
+    mhod_settings = b''
+    settings_count = 0
+    if raw_mhod102 is not None:
+        mhod_settings = write_mhod102(raw_mhod102)
+        settings_count = 1
+
+    # Build library index MHODs for master playlist (type 52/53 pairs)
+    # These are REQUIRED for iPod Classic to build its browsing views
+    library_indices_data = b''
+    library_indices_count = 0
+    if master and tracks:
+        library_indices_data, library_indices_count = write_library_indices(tracks, capabilities=capabilities)
+
+    # Build MHIP entries for each track
+    mhip_count: int
+    if podcast_grouping and track_album_map is not None:
+        # Podcast grouping: group tracks by album (libgpod write_podcast_mhips)
+        mhip_data, mhip_count = _build_podcast_grouped_mhips(
+            track_ids, track_album_map, next_mhip_id_start,
+        )
+    else:
+        # Standard flat MHIP list (write_playlist_mhips)
+        # When item_metadata is provided (round-trip from parsed data), we
+        # preserve per-MHIP fields: podcastGroupFlag, groupID, podcastGroupRef.
+        mhips = []
+        for i, track_id in enumerate(track_ids):
+            meta = item_metadata[i] if item_metadata and i < len(item_metadata) else None
+            mhip = write_mhip(
+                track_id, position=i,
+                mhip_id=meta.group_id if meta else 0,
+                podcast_group_flag=meta.podcast_group_flag if meta else 0,
+                podcast_group_ref=meta.podcast_group_ref if meta else 0,
+                track_persistent_id=meta.track_persistent_id if meta else 0,
+                mhip_persistent_id=meta.mhip_persistent_id if meta else 0,
+            )
+            mhips.append(mhip)
+        mhip_data = b''.join(mhips)
+        mhip_count = len(track_ids)
+
+    # Count MHODs (title + playlist prefs + smart + settings + library indices)
+    mhod_count = 2 + smart_mhod_count + settings_count + library_indices_count
+
+    # Total chunk length
+    total_length = (
+        MHYP_HEADER_SIZE + len(mhod_title) + len(mhod_playlist) + len(mhod_smart) + len(mhod_settings) + len(library_indices_data) + len(mhip_data)
+    )
+
+    # Build MHYP header
+    header = bytearray(MHYP_HEADER_SIZE)
+    write_generic_header(header, 0, b'mhyp', MHYP_HEADER_SIZE, total_length)
+
+    # Build values dict for write_fields.
+    # Timestamps are Unix epoch — write_transform (unix_to_mac) handles conversion.
+    values: dict[str, int] = {
+        'mhod_child_count': mhod_count,
+        'mhip_child_count': mhip_count,
+        'master_flag': 1 if master else 0,
+        'timestamp': timestamp,
+        'playlist_id': playlist_id,
+        'string_mhod_child_count': 1,
+        'podcast_flag': podcast_flag,
+        'sort_order': sortorder,
+        'timestamp_2': timestamp,
+    }
+
+    # Non-master playlists write db_id_2 and playlist_id at extended offsets.
+    # For master=True (ds2 master and ds5 built-in categories), these stay
+    # zeroed — matching libgpod behaviour.
+    if not master:
+        values['db_id_2'] = db_id_2
+        values['playlist_id_2'] = playlist_id
+
+    # mhsd5_type — browsing category for dataset 5 smart playlists.
+    # libgpod writes the same value at +0x50 and +0x52, plus a
+    # special flag at +0x54 for RINGTONES(6) and MOVIE_RENTALS(7).
+    if mhsd5_type:
+        values['mhsd5_type'] = mhsd5_type
+        values['mhsd5_type_2'] = mhsd5_type
+        if mhsd5_type in (6, 7):
+            values['mhsd5_special_flag'] = 0x200
+
+    write_fields(header, 0, 'mhyp', values, MHYP_HEADER_SIZE)
+
+    return (
+        bytes(header) + mhod_title + mhod_playlist + mhod_smart + mhod_settings + library_indices_data + mhip_data
+    )
+
+
+def _build_podcast_grouped_mhips(
+    track_ids: List[int],
+    track_album_map: dict[int, str],
+    next_id: int,
+) -> tuple[bytes, int]:
+    """Build podcast-grouped MHIP entries for the type 3 MHSD dataset.
+
+    Groups tracks by album name.  For each album group, emits:
+      1. A group header MHIP (``podcast_group_flag=256``, ``track_id=0``,
+         MHOD type 1 with the album name)
+      2. One child MHIP per track (``podcast_group_flag=0``,
+         ``group_id_ref`` pointing to the parent group header's ``group_id``,
+         MHOD type 100 with the child's own unique ``mhip_id`` as position)
+
+    This matches libgpod's ``write_podcast_mhips()`` +
+    ``write_one_podcast_group()`` in ``itdb_itunesdb.c``.
+
+    Args:
+        track_ids: Sequential track IDs for the podcast playlist
+        track_album_map: track_id → album name ('' if unknown)
+        next_id: Starting value for unique MHIP group_id / mhip_id
+
+    Returns:
+        (mhip_bytes, mhip_count) — concatenated MHIPs and the total
+        MHIP count (= number of tracks + number of album groups).
+    """
+    from collections import OrderedDict
+
+    # Group tracks by album, preserving insertion order
+    album_groups: OrderedDict[str, list[int]] = OrderedDict()
+    for tid in track_ids:
+        album = track_album_map.get(tid, "")
+        album_groups.setdefault(album, []).append(tid)
+
+    parts: list[bytes] = []
+    cur_id = next_id
+    total_mhip_count = 0
+
+    for album, tids in album_groups.items():
+        # Group header MHIP
+        group_id = cur_id
+        cur_id += 1
+        parts.append(write_mhip_podcast_group(album or "Unknown", group_id))
+        total_mhip_count += 1
+
+        # Child MHIPs — one per track in this album group
+        for tid in tids:
+            mhip_id = cur_id
+            cur_id += 1
+            parts.append(write_mhip(
+                tid, position=mhip_id,
+                mhip_id=mhip_id,
+                podcast_group_flag=0,
+                podcast_group_ref=group_id,
+            ))
+            total_mhip_count += 1
+
+    return b''.join(parts), total_mhip_count
+
+
+def write_mhod_playlist_prefs() -> bytes:
+    """
+    Write the playlist preferences MHOD (type 100).
+
+    This is a binary blob containing display/sorting preferences.
+    Based on libgpod's mk_long_mhod_id_playlist().
+
+    Total size: 0x288 (648) bytes as written by iTunes.
+    """
+    # libgpod mk_long_mhod_id_playlist() writes exactly 0x288 bytes
+    # This is critical for proper playlist recognition
+
+    total_len = 0x288  # 648 bytes - exactly what libgpod writes
+
+    # Build complete MHOD type 100
+    data = bytearray(total_len)
+
+    # Header (24 bytes) — use shared helper, then overlay onto data buffer
+    hdr = write_mhod_header(100, total_len)
+    data[:_MHOD_HEADER_SIZE] = hdr
+
+    # Body data - based on libgpod mk_long_mhod_id_playlist()
+    # Offset 0x18 (after header):
+    struct.pack_into('<I', data, 0x18, 0)        # 6 x 0s
+    struct.pack_into('<I', data, 0x1C, 0)
+    struct.pack_into('<I', data, 0x20, 0)
+    struct.pack_into('<I', data, 0x24, 0)
+    struct.pack_into('<I', data, 0x28, 0)
+    struct.pack_into('<I', data, 0x2C, 0)
+
+    struct.pack_into('<I', data, 0x30, 0x010084)  # magic value from libgpod
+    struct.pack_into('<I', data, 0x34, 0x05)      # ?
+    struct.pack_into('<I', data, 0x38, 0x09)      # ?
+    struct.pack_into('<I', data, 0x3C, 0x03)      # ?
+    struct.pack_into('<I', data, 0x40, 0x120001)  # ?
+    struct.pack_into('<I', data, 0x44, 0)         # ?
+    struct.pack_into('<I', data, 0x48, 0)         # ?
+    struct.pack_into('<I', data, 0x4C, 0x640014)  # ?
+    struct.pack_into('<I', data, 0x50, 0x01)      # bool? (visible?)
+    struct.pack_into('<I', data, 0x54, 0)         # 2x0
+    struct.pack_into('<I', data, 0x58, 0)
+    struct.pack_into('<I', data, 0x5C, 0x320014)  # ?
+    struct.pack_into('<I', data, 0x60, 0x01)      # bool? (visible?)
+    struct.pack_into('<I', data, 0x64, 0)         # 2x0
+    struct.pack_into('<I', data, 0x68, 0)
+    struct.pack_into('<I', data, 0x6C, 0x5a0014)  # ?
+    struct.pack_into('<I', data, 0x70, 0x01)      # bool? (visible?)
+    struct.pack_into('<I', data, 0x74, 0)         # 2x0
+    struct.pack_into('<I', data, 0x78, 0)
+    struct.pack_into('<I', data, 0x7C, 0x500014)  # ?
+    struct.pack_into('<I', data, 0x80, 0x01)      # bool? (visible?)
+    struct.pack_into('<I', data, 0x84, 0)         # 2x0
+    struct.pack_into('<I', data, 0x88, 0)
+    struct.pack_into('<I', data, 0x8C, 0x7d0015)  # ?
+    struct.pack_into('<I', data, 0x90, 0x01)      # bool? (visible?)
+    # Rest is zeros (padding to 0x288)
+
+    return bytes(data)
+
+
+def _write_mhod100_raw(raw_body: bytes) -> bytes:
+    """Write an MHOD type 100 from a raw body blob (round-trip passthrough).
+
+    Args:
+        raw_body: Body bytes (everything after the 24-byte MHOD header).
+
+    Returns:
+        Complete MHOD type 100 chunk.
+    """
+    total_len = _MHOD_HEADER_SIZE + len(raw_body)
+    return write_mhod_header(100, total_len) + raw_body
+
+
+def write_playlist(
+    playlist: "PlaylistInfo",
+    db_id_2: int = 0,
+    podcast_grouping: bool = False,
+    track_album_map: Optional[dict[int, str]] = None,
+    next_mhip_id_start: int = 1,
+) -> bytes:
+    """Write a playlist from a PlaylistInfo dataclass.
+
+    Handles regular playlists, smart playlists, AND dataset 5 built-in
+    categories.  For dataset 5, PlaylistInfo.master will be True (setting
+    the type byte at +0x14 to 1) and track_ids will be empty (the iPod
+    firmware evaluates smart rules at runtime).
+
+    The *master playlist* for dataset 2 is NOT written through this
+    function — use write_master_playlist() instead.
+
+    Args:
+        playlist: A PlaylistInfo instance.
+        db_id_2: Database-wide ID from MHBD offset 0x24.
+        podcast_grouping: When True and playlist.podcast_flag is set,
+                     generate grouped MHIPs for podcast episodes.
+        track_album_map: track_id → album name (required when
+                     podcast_grouping applies).
+        next_mhip_id_start: Starting ID for generated MHIP identifiers
+                     during podcast grouping.
+
+    Returns:
+        Complete MHYP chunk bytes.
+    """
+    # Only apply podcast grouping to actual podcast playlists
+    use_grouping = podcast_grouping and bool(playlist.podcast_flag)
+    return write_mhyp(
+        name=playlist.name,
+        track_ids=playlist.track_ids,
+        playlist_id=playlist.playlist_id,
+        master=playlist.master,
+        sortorder=playlist.sortorder,
+        podcast_flag=playlist.podcast_flag,
+        db_id_2=db_id_2,
+        smart_prefs=playlist.smart_prefs,
+        smart_rules=playlist.smart_rules,
+        mhsd5_type=playlist.mhsd5_type,
+        raw_mhod100=playlist.raw_mhod100,
+        raw_mhod102=playlist.raw_mhod102,
+        item_metadata=playlist.item_metadata,
+        podcast_grouping=use_grouping,
+        track_album_map=track_album_map,
+        next_mhip_id_start=next_mhip_id_start,
+    )
+
+
+def write_master_playlist(
+    track_ids: List[int],
+    db_id_2: int,
+    name: str = "iPod",
+    tracks: Optional[List["TrackInfo"]] = None,
+    capabilities=None,
+    playlist_id: Optional[int] = None,
+) -> bytes:
+    """
+    Write the Master Playlist (MPL).
+
+    The master playlist is required and must be the first playlist.
+    It contains references to ALL tracks in the database.
+
+    Args:
+        track_ids: List of ALL track IDs in the database
+        name: Playlist name (usually "iPod" or device name)
+        tracks: List of ALL TrackInfo objects (needed for library indices)
+        db_id_2: Database-wide ID from MHBD offset 0x24
+        capabilities: Optional DeviceCapabilities for video sort indices.
+
+    Returns:
+        Complete MHYP chunk for master playlist
+    """
+    # Master playlist MUST have master=True (0x14 field = 1)
+    # This is how iTunes/iPod identifies the master playlist
+    return write_mhyp(
+        name=name,
+        track_ids=track_ids,
+        playlist_id=playlist_id,
+        master=True,  # CRITICAL: Master playlist must have type=1
+        sortorder=5,  # Match iTunes default sort order
+        tracks=tracks,
+        db_id_2=db_id_2,
+        capabilities=capabilities,
+    )

src/vendor/ipod_device/__init__.py

@@ -0,0 +1,148 @@
+"""
+ipod_device — unified iPod device identification & management package.
+
+Re-exports device-identification and model-capability APIs that were
+historically spread across multiple legacy modules.
+"""
+
+# flake8: noqa: F401
+
+# ── artwork ──────────────────────────────────────────────────────────
+from .artwork import (
+    ARTWORK_FORMATS_BY_ID,
+    ITHMB_FORMAT_MAP,
+    ITHMB_SIZE_MAP,
+    cover_art_format_definitions_for_device,
+    ithmb_formats_for_device,
+    photo_formats_for_device,
+    resolve_cover_art_format_definitions,
+    resolve_cover_art_format_definitions_for_device,
+)
+
+# ── authority ────────────────────────────────────────────────────────
+from .authority import (
+    AUTHORITY_FILENAME,
+    SOURCE_RANK,
+    SYSINFO_FIELDS,
+    cache_sysinfo_extended,
+    check_authority_coverage,
+    read_authority,
+    update_sysinfo,
+)
+
+# ── capabilities ─────────────────────────────────────────────────────
+from .capabilities import (
+    ArtworkFormat,
+    DeviceCapabilities,
+    capabilities_for_family_gen,
+    checksum_type_for_family_gen,
+    cover_art_formats_for_family_gen,
+)
+from .checksum import (
+    CHECKSUM_MHBD_SCHEME,
+    MHBD_SCHEME_TO_CHECKSUM,
+    ChecksumType,
+)
+
+# ── images ───────────────────────────────────────────────────────────
+from .images import (
+    COLOR_MAP,
+    FAMILY_FALLBACK,
+    GENERIC_IMAGE,
+    IMAGE_COLORS,
+    MODEL_IMAGE,
+    color_for_image,
+    image_for_model,
+    resolve_image_filename,
+)
+
+# ── info (device_info) ───────────────────────────────────────────────
+from .info import (
+    DeviceInfo,
+    clear_current_device,
+    detect_checksum_type,
+    enrich,
+    generate_library_id,
+    get_current_device,
+    get_firewire_id,
+    itdb_write_filename,
+    read_sysinfo,
+    resolve_itdb_path,
+    set_current_device,
+)
+
+# ── lookup ───────────────────────────────────────────────────────────
+from .lookup import (
+    extract_model_number,
+    get_friendly_model_name,
+    get_model_info,
+    infer_generation,
+    lookup_by_serial,
+)
+
+# ── models ───────────────────────────────────────────────────────────
+from .models import (
+    IPOD_MODELS,
+    IPOD_USB_PIDS,
+    SERIAL_LAST3_TO_MODEL,
+    USB_PID_TO_MODEL,
+)
+
+# ── sysinfo parsing/evidence ─────────────────────────────────────────
+from .sysinfo import (
+    DeviceEvidence,
+    EvidenceValue,
+    ParsedSysInfoExtended,
+    identity_from_sysinfo,
+    identity_from_sysinfo_extended,
+    parse_sysinfo_extended,
+    parse_sysinfo_text,
+)
+
+# ── virtual iPods ─────────────────────────────────────────────────────
+from .virtual import (
+    VIRTUAL_IPOD_INFO_FILENAME,
+    available_virtual_ipod_models,
+    create_virtual_ipod,
+    ensure_virtual_itunes_database,
+    has_virtual_ipod_info,
+    load_virtual_ipod_info,
+    virtual_ipod_info_path,
+)
+
+# ── checksum ─────────────────────────────────────────────────────────
+from .vpd_libusb import (
+    identify_via_vpd,
+)
+from .vpd_libusb import (
+    query_all_ipods as usb_query_all_ipods,
+)
+
+# ── vpd_libusb ───────────────────────────────────────────────────────
+from .vpd_libusb import (
+    query_ipod_vpd as usb_query_ipod_vpd,
+)
+from .vpd_libusb import (
+    write_sysinfo as usb_write_sysinfo,
+)
+from .vpd_usb_control import (
+    query_all_ipod_usb_sysinfo_extended,
+    query_ipod_usb_sysinfo_extended,
+)
+
+try:
+    from .vpd_linux import query_ipod_vpd_for_path as linux_query_ipod_vpd_for_path
+except ImportError:
+    pass
+
+try:
+    from .vpd_windows import query_ipod_vpd_for_path as windows_query_ipod_vpd_for_path
+except ImportError:
+    pass
+
+# ── vpd_iokit is macOS-only and raises ImportError on other platforms,
+#    so we don't import it at package level.  Import directly:
+#        from ipod_device.vpd_iokit import query_ipod_vpd
+
+# ── scanner (GUI/device_scanner) ────────────────────────────────────
+from .scanner import identify_ipod_at_path, scan_for_ipods

src/vendor/ipod_device/artwork.py

@@ -0,0 +1,184 @@
+"""Artwork lookups backed by the canonical format registry."""
+
+from .artwork_presets import (
+    ARTWORK_FORMATS_BY_ID,
+    ArtworkFormat,
+)
+from .capabilities import capabilities_for_family_gen, cover_art_formats_for_family_gen
+
+ITHMB_FORMAT_MAP = ARTWORK_FORMATS_BY_ID
+"""Primary global lookup of ithmb correlation ID -> ``ArtworkFormat``.
+
+Most artwork IDs are globally meaningful. Device-aware code can layer a small
+override set on top of this table for the few known conflicts, such as Nano
+7G's reinterpretation of ``1013``/``1015``/``1016``.
+"""
+
+ITHMB_SIZE_MAP: dict[int, ArtworkFormat] = {}
+"""Fallback lookup: byte size -> ``ArtworkFormat``."""
+for _af in ITHMB_FORMAT_MAP.values():
+    _byte_size = _af.row_bytes * _af.height
+    if _byte_size > 0 and _byte_size not in ITHMB_SIZE_MAP:
+        ITHMB_SIZE_MAP[_byte_size] = _af
+
+
+def ithmb_formats_for_device(
+    family: str,
+    generation: str,
+    *,
+    capacity: str | None = None,
+    model_number: str | None = None,
+) -> dict[int, tuple[int, int]]:
+    """Return ``{correlation_id: (width, height)}`` for a device's cover art."""
+    definitions = cover_art_format_definitions_for_device(
+        family,
+        generation,
+        capacity=capacity,
+        model_number=model_number,
+    )
+    return {fid: (af.width, af.height) for fid, af in definitions.items()}
+
+
+def _format_dict(formats: tuple[ArtworkFormat, ...]) -> dict[int, ArtworkFormat]:
+    return {af.format_id: af for af in formats}
+
+
+def cover_art_format_definitions_for_device(
+    family: str,
+    generation: str,
+    *,
+    capacity: str | None = None,
+    model_number: str | None = None,
+) -> dict[int, ArtworkFormat]:
+    """Return the device's required cover-art definitions.
+
+    The normal case is the global registry. Devices with known conflicting IDs
+    expose a small explicit override set through their capability profile.
+    """
+
+    caps = capabilities_for_family_gen(
+        family,
+        generation or "",
+        capacity=capacity,
+        model_number=model_number,
+    )
+    if caps is None:
+        return _format_dict(
+            cover_art_formats_for_family_gen(
+                family,
+                generation,
+                capacity=capacity,
+                model_number=model_number,
+            )
+        )
+    if not caps.supports_artwork:
+        return {}
+    return _format_dict(caps.cover_art_formats)
+
+
+def _resolve_observed_format(
+    format_id: int,
+    width: int,
+    height: int,
+    preferred_defs: dict[int, ArtworkFormat],
+) -> ArtworkFormat:
+    """Resolve an observed ``id -> dimensions`` using overrides first, then global defaults.
+
+    If neither source matches the observed dimensions, fall back to a generic
+    RGB565 cover-art definition for that observed shape.
+    """
+    for candidate in (
+        preferred_defs.get(format_id),
+        ARTWORK_FORMATS_BY_ID.get(format_id),
+    ):
+        if candidate is None:
+            continue
+        if int(candidate.width) == int(width) and int(candidate.height) == int(height):
+            return candidate
+
+    return ArtworkFormat(
+        int(format_id),
+        int(width),
+        int(height),
+        int(width) * 2,
+        "RGB565_LE",
+        "cover",
+        f"Device artwork format {format_id}",
+    )
+
+
+def resolve_cover_art_format_definitions(
+    family: str = "",
+    generation: str = "",
+    *,
+    capacity: str | None = None,
+    model_number: str | None = None,
+    observed_formats: dict[int, tuple[int, int]] | None = None,
+) -> dict[int, ArtworkFormat]:
+    """Resolve the authoritative cover-art definitions for a device.
+
+    ``observed_formats`` usually comes from SysInfoExtended or an existing
+    ArtworkDB. When present, its ID list is authoritative, but each entry still
+    resolves through device overrides first and the global registry second. Only
+    unmatched dimensions fall back to a generic inferred definition.
+    """
+    preferred_defs = cover_art_format_definitions_for_device(
+        family,
+        generation,
+        capacity=capacity,
+        model_number=model_number,
+    )
+
+    if observed_formats:
+        resolved: dict[int, ArtworkFormat] = {}
+        for fid, dims in observed_formats.items():
+            width, height = dims
+            resolved[int(fid)] = _resolve_observed_format(
+                int(fid),
+                int(width),
+                int(height),
+                preferred_defs,
+            )
+        return resolved
+
+    return preferred_defs
+
+
+def resolve_cover_art_format_definitions_for_device(device) -> dict[int, ArtworkFormat]:
+    """Resolve cover-art definitions from a ``DeviceInfo``-like object."""
+    if device is None:
+        return {}
+
+    return resolve_cover_art_format_definitions(
+        getattr(device, "model_family", "") or "",
+        getattr(device, "generation", "") or "",
+        capacity=getattr(device, "capacity", ""),
+        model_number=getattr(device, "model_number", ""),
+        observed_formats=getattr(device, "artwork_formats", None) or None,
+    )
+
+
+def photo_formats_for_device(
+    family: str,
+    generation: str,
+    *,
+    capacity: str | None = None,
+    model_number: str | None = None,
+) -> dict[int, ArtworkFormat]:
+    """Return device-specific photo ithmb formats.
+
+    This is separate from cover-art formats because iPods keep slide-show/photo
+    caches in the ``Photos`` hierarchy rather than ``ArtworkDB``. The per-device
+    formats are sourced from ``DeviceCapabilities.photo_formats``.
+    """
+
+    caps = capabilities_for_family_gen(
+        family,
+        generation or "",
+        capacity=capacity,
+        model_number=model_number,
+    )
+    formats = caps.photo_formats if caps is not None else ()
+    if not formats:
+        return {}
+    return {af.format_id: af for af in formats}

src/vendor/ipod_device/artwork_presets.py

@@ -0,0 +1,119 @@
+"""Canonical ithmb artwork format definitions.
+
+Sources:
+  - libgpod ``src/itdb_device.c`` fallback artwork tables
+  - Keith's iPod Photo Reader README (model/prefix cross-checks)
+  - cyianor/ithmbrdr README (1067 photo payload confirmation)
+  - local iTunes-authored Nano 7G artwork dump (F1010/F1013/F1015/F1016)
+
+The global registry below is the default source of truth for artwork IDs.
+Only a very small number of device families are known to reinterpret IDs,
+so those conflicts are modeled as explicit overrides rather than treating
+the whole ID space as device-specific.
+"""
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class ArtworkFormat:
+    """One ithmb artwork format definition."""
+
+    format_id: int
+    width: int
+    height: int
+    row_bytes: int
+    pixel_format: str = "RGB565_LE"
+    role: str = "cover"
+    description: str = ""
+
+
+ARTWORK_FORMATS_BY_ID: dict[int, ArtworkFormat] = {
+    # iPod Photo / Video era
+    1005: ArtworkFormat(1005, 80, 80, 160, "RGB565_LE", "photo_thumb", "Nano 7G photo thumbnail"),
+    1007: ArtworkFormat(1007, 480, 864, 960, "RGB565_LE", "photo_full", "Nano 7G photo full screen"),
+    1009: ArtworkFormat(1009, 42, 30, 84, "RGB565_LE", "photo_list", "Photo list thumbnail"),
+    1010: ArtworkFormat(1010, 240, 240, 480, "RGB565_LE", "cover_large", "Nano 7G album art large"),
+    1013: ArtworkFormat(1013, 220, 176, 440, "RGB565_BE_90", "photo_full", "Photo full screen (rotated)"),
+    1015: ArtworkFormat(1015, 130, 88, 260, "RGB565_LE", "photo_preview", "Photo/Video preview"),
+    1016: ArtworkFormat(1016, 140, 140, 280, "RGB565_LE", "cover_large", "Photo album art large"),
+    1017: ArtworkFormat(1017, 56, 56, 112, "RGB565_LE", "cover_small", "Photo album art small"),
+    1019: ArtworkFormat(1019, 720, 480, 1440, "UYVY", "tv_out", "Photo/Video NTSC TV output"),
+    # Compatibility alias preserved from existing Apple databases.
+    1020: ArtworkFormat(1020, 220, 176, 440, "RGB565_BE_90", "photo_full", "Photo full screen (alt rotated)"),
+    1023: ArtworkFormat(1023, 176, 132, 352, "RGB565_BE", "photo_full", "Nano full screen"),
+    1024: ArtworkFormat(1024, 320, 240, 640, "RGB565_LE", "photo_full", "320x240 photo full screen"),
+    1027: ArtworkFormat(1027, 100, 100, 200, "RGB565_LE", "cover_large", "Nano album art large"),
+    1028: ArtworkFormat(1028, 100, 100, 200, "RGB565_LE", "cover_small", "Video album art small"),
+    1029: ArtworkFormat(1029, 200, 200, 400, "RGB565_LE", "cover_large", "Video album art large"),
+    1031: ArtworkFormat(1031, 42, 42, 84, "RGB565_LE", "cover_small", "Nano album art small"),
+    1032: ArtworkFormat(1032, 42, 37, 84, "RGB565_LE", "photo_list", "Nano list thumbnail"),
+    1036: ArtworkFormat(1036, 50, 41, 100, "RGB565_LE", "photo_list", "Video list thumbnail"),
+    # Classic / later click-wheel iPods
+    # Compatibility alias preserved from existing Apple databases.
+    1044: ArtworkFormat(1044, 128, 128, 256, "RGB565_LE", "cover_medium", "Classic album art medium"),
+    1055: ArtworkFormat(1055, 128, 128, 256, "RGB565_LE", "cover_medium", "Classic album art medium"),
+    1056: ArtworkFormat(1056, 128, 128, 256, "RGB565_LE", "cover_medium_alt", "128x128 cover art (alternate)"),
+    1060: ArtworkFormat(1060, 320, 320, 640, "RGB565_LE", "cover_large", "Classic album art large"),
+    1061: ArtworkFormat(1061, 56, 56, 112, "RGB565_LE", "cover_small", "Classic album art small"),
+    1066: ArtworkFormat(1066, 64, 64, 128, "RGB565_LE", "photo_thumb", "Classic photo thumbnail"),
+    1067: ArtworkFormat(1067, 720, 480, 1080, "I420_LE", "tv_out", "Classic TV output (YUV)"),
+    1068: ArtworkFormat(1068, 128, 128, 256, "RGB565_LE", "cover_medium_alt", "Classic album art medium (alt 2)"),
+    1071: ArtworkFormat(1071, 240, 240, 480, "RGB565_LE", "cover_large", "Nano 4G album art large"),
+    1073: ArtworkFormat(1073, 240, 240, 480, "RGB565_LE", "cover_large", "Nano 5G/6G album art large"),
+    1074: ArtworkFormat(1074, 50, 50, 100, "RGB565_LE", "cover_xsmall", "Nano album art tiny"),
+    1078: ArtworkFormat(1078, 80, 80, 160, "RGB565_LE", "cover_small", "Nano 4G/5G album art small"),
+    1079: ArtworkFormat(1079, 80, 80, 160, "RGB565_LE", "photo_thumb", "Nano 4G/5G photo thumbnail"),
+    1081: ArtworkFormat(1081, 640, 480, 0, "JPEG", "photo_full", "JPEG photo format (experimental/legacy)"),
+    1083: ArtworkFormat(1083, 240, 320, 480, "RGB565_LE", "photo_full", "Nano 4G photo full screen (portrait)"),
+    1084: ArtworkFormat(1084, 240, 240, 480, "RGB565_LE", "cover_large_alt", "Nano 4G album art (alt)"),
+    # Newer iPod-only formats beyond libgpod's older hardcoded tables.
+    1085: ArtworkFormat(1085, 88, 88, 176, "RGB565_LE", "cover_medium", "Nano 6G album art medium"),
+    1087: ArtworkFormat(1087, 384, 384, 768, "RGB565_LE", "photo_large", "Nano 5G photo large"),
+    1089: ArtworkFormat(1089, 58, 58, 116, "RGB565_LE", "cover_small", "Nano 6G album art small"),
+    1092: ArtworkFormat(1092, 80, 80, 160, "RGB565_LE", "photo_thumb", "Nano 6G photo thumbnail"),
+    1093: ArtworkFormat(1093, 512, 512, 1024, "RGB565_LE", "photo_full", "Nano 6G photo full screen"),
+    # Mobile / touch-era formats
+    2002: ArtworkFormat(2002, 50, 50, 100, "RGB565_BE", "cover_small", "iPod Mobile cover art small"),
+    2003: ArtworkFormat(2003, 150, 150, 300, "RGB565_BE", "cover_large", "iPod Mobile cover art large"),
+    3001: ArtworkFormat(3001, 256, 256, 512, "REC_RGB555_LE", "cover_large", "iPod touch cover art large"),
+    3002: ArtworkFormat(3002, 128, 128, 256, "REC_RGB555_LE", "cover_medium", "iPod touch cover art medium"),
+    3003: ArtworkFormat(3003, 64, 64, 128, "REC_RGB555_LE", "cover_small", "iPod touch cover art small"),
+    3005: ArtworkFormat(3005, 320, 320, 640, "RGB555_LE", "cover_xlarge", "iPod touch cover art xlarge"),
+}
+
+
+CLASSIC_COVER_ART_FORMATS = (
+    ARTWORK_FORMATS_BY_ID[1055],
+    ARTWORK_FORMATS_BY_ID[1060],
+    ARTWORK_FORMATS_BY_ID[1061],
+    ARTWORK_FORMATS_BY_ID[1068],
+)
+"""Cover-art formats used by click-wheel iPod Classic generations."""
+
+
+NANO_7G_COVER_ART_OVERRIDES = (
+    ARTWORK_FORMATS_BY_ID[1010],
+    ArtworkFormat(1013, 50, 50, 100, "RGB565_LE", "cover_xsmall", "Nano 7G album art tiny"),
+    ArtworkFormat(1015, 58, 58, 116, "RGB565_LE", "cover_small", "Nano 7G album art small"),
+    ArtworkFormat(1016, 57, 57, 116, "RGB565_LE", "cover_small_alt", "Nano 7G album art small (aligned)"),
+)
+"""Known Nano 7G overrides for a few globally-defined artwork IDs."""
+
+
+# Backward-compatible alias used by capability tables and existing imports.
+NANO_7G_COVER_ART_FORMATS = NANO_7G_COVER_ART_OVERRIDES
+
+
+def artwork_format_candidates() -> tuple[ArtworkFormat, ...]:
+    """Return the global registry plus the small set of known override variants."""
+    candidates = [
+        *ARTWORK_FORMATS_BY_ID.values(),
+        *CLASSIC_COVER_ART_FORMATS,
+        *NANO_7G_COVER_ART_OVERRIDES,
+    ]
+    unique: dict[tuple[int, int, int, str], ArtworkFormat] = {}
+    for fmt in candidates:
+        key = (fmt.format_id, fmt.width, fmt.height, fmt.pixel_format)
+        unique.setdefault(key, fmt)
+    return tuple(unique.values())

src/vendor/ipod_device/authority.py

@@ -0,0 +1,671 @@
+"""
+iOpenPod SysInfo Authority — manages authoritative SysInfo writing.
+
+After device identification is complete, reconciles gathered data with
+the existing SysInfo file on the iPod, using per-field provenance tracking
+to keep the most reliable value for each field.
+
+The authority file at ``/iPod_Control/Device/iOpenPodSysInfoAuthority``
+(JSON) records which data source was used to populate each SysInfo field.
+On subsequent runs, if a field's value has changed, the authority
+determines whether the new or existing value is more trustworthy.
+
+Source reliability (most → least)::
+
+    Sure (live hardware):
+        scsi_vpd / windows_scsi / linux_scsi / usb_vendor > vpd > iokit > ioctl
+            > device_tree / ioreg / sysfs > wmi
+    Guesses (files / lookups / derivations):
+        sysinfo_extended > sysinfo > itunes > serial_lookup
+            > usb_pid > hashing > unknown
+"""
+
+from __future__ import annotations
+
+import hashlib
+import json
+import logging
+import os
+from datetime import UTC, datetime
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from .info import DeviceInfo
+
+logger = logging.getLogger(__name__)
+
+
+# ──────────────────────────────────────────────────────────────────────
+# Source reliability ranking — lower index = more reliable
+# ──────────────────────────────────────────────────────────────────────
+
+_SOURCE_ORDER: list[str] = [
+    # ── Sure: live hardware probes ──────────────────────────────────
+    "scsi_vpd",             # Live SCSI INQUIRY VPD plist
+    "windows_scsi",         # Windows SCSI pass-through VPD
+    "linux_scsi",           # Linux SG_IO SCSI pass-through VPD
+    "usb_vendor",           # Live Apple USB vendor-control plist
+    "vpd",                  # SCSI Vital Product Data — gold standard
+    "iokit",                # macOS IOKit SCSI (effectively VPD, no unmount)
+    "ioctl",                # Windows direct SCSI inquiry
+    "device_tree",          # Windows PnP device tree (live hardware)
+    "ioreg",                # macOS ioreg (live hardware)
+    "sysfs",                # Linux sysfs (live hardware)
+    "wmi",                  # Windows WMI (live hardware query)
+    # ── Guesses: lookups, derivations, files ────────────────────────
+    "itunes",               # Pre-existing value assumed to be from iTunes
+    "serial_lookup",        # Derived from serial last-3 chars
+    "usb_pid",              # Coarse USB PID mapping
+    "disk_size",            # Live disk-size based capacity estimate
+    "model_table",          # Deterministic inference from known model tuples
+    "inferred",             # Other deterministic inference from known fields
+    "sysinfo_extended",     # SysInfoExtended XML plist — on-disk, stale-prone
+    "sysinfo",              # SysInfo plain text — on-disk, stale-prone
+    "hashing",              # Inferred from hashing scheme
+    "unknown",              # Source not tracked
+]
+
+SOURCE_RANK: dict[str, int] = {src: i for i, src in enumerate(_SOURCE_ORDER)}
+"""Map source name → rank (lower = more reliable)."""
+
+_WORST_RANK: int = len(_SOURCE_ORDER)
+
+# Anything with rank < _SURE_THRESHOLD is a "sure" (live hardware) source.
+# Anything >= is a "guess" (file / lookup / derivation).
+_SURE_THRESHOLD: int = SOURCE_RANK["itunes"]  # first guess source
+
+
+# ──────────────────────────────────────────────────────────────────────
+# SysInfo key ↔ DeviceInfo field mapping
+# ──────────────────────────────────────────────────────────────────────
+
+SYSINFO_FIELDS: list[tuple[str, str]] = [
+    # ── Core identifiers (written by iTunes / hardware probes) ────────
+    ("pszSerialNumber", "serial"),
+    ("FirewireGuid", "firewire_guid"),
+    ("visibleBuildID", "firmware"),
+    ("BoardHwName", "board"),
+    ("ModelNumStr", "model_number"),
+    ("FamilyID", "family_id"),
+    ("UpdaterFamilyID", "updater_family_id"),
+    # ── Derived / resolved by iOpenPod for full device granularity ────
+    # These are deterministically derived from model_number (via
+    # IPOD_MODELS or serial-last-3 lookup), but caching them in SysInfo
+    # avoids re-derivation and lets the authority system track provenance.
+    ("ModelFamily", "model_family"),
+    ("Generation", "generation"),
+    ("Capacity", "capacity"),
+    ("Color", "color"),
+    ("USBProductID", "usb_pid"),
+]
+
+# Fields whose default DeviceInfo value is a non-empty sentinel that should
+# NOT be treated as "already populated" when reading from SysInfo.
+# model_family defaults to "iPod" (generic, unresolved).
+_SENTINEL_DEFAULTS: dict[str, str] = {
+    "model_family": "iPod",
+}
+
+_DERIVED_SYSINFO_KEYS: frozenset[str] = frozenset({
+    "ModelFamily",
+    "Generation",
+    "Capacity",
+    "Color",
+    "USBProductID",
+})
+
+# Core identification fields — these drive the "all sure" determination for
+# the HIGH authority path.  If ALL core fields have sure (live hardware)
+# provenance, the expensive hardware and VPD probes are skipped.
+#
+# Only the essential identification trio is included:
+#   - Serial number (needed for serial-last-3 exact model resolution)
+#   - FireWire GUID (needed for database signing)
+#   - Model number (needed for family/gen/capacity/color derivation)
+#
+# Other fields (firmware, board) are informational — their absence from
+# live hardware probes should NOT force re-probing.  Derived fields
+# (ModelFamily, Generation, etc.) are excluded because they inherit trust
+# from a core field and don't require independent hardware probing.
+_CORE_FIELDS: frozenset[str] = frozenset({
+    "pszSerialNumber",
+    "FirewireGuid",
+    "ModelNumStr",
+})
+
+AUTHORITY_FILENAME = "iOpenPodSysInfoAuthority"
+
+
+# ──────────────────────────────────────────────────────────────────────
+# Authority coverage check
+# ──────────────────────────────────────────────────────────────────────
+
+def check_authority_coverage(
+    ipod_path: str,
+) -> tuple[bool, dict[str, str]]:
+    """Check whether the authority file indicates core fields are all tracked.
+
+    Returns ``(all_tracked, field_sources)`` where:
+
+    * *all_tracked* is ``True`` when every **core** SysInfo field has an
+      authority entry (i.e., iOpenPod has previously identified this device
+      and cached the results).  The SysInfo is trusted as high-authority
+      because either (a) it was written by iTunes, or (b) iOpenPod wrote
+      it after probing hardware.  The only things that invalidate trust
+      are external modification (detected via SHA-256 hashes) or missing
+      authority file (first run).
+    * *field_sources* maps DeviceInfo field names to their authority source
+      strings (e.g. ``{"serial": "vpd", "firewire_guid": "ioctl", ...}``).
+
+    If the authority file is missing or empty, returns ``(False, {})`` so
+    that the caller runs the full probe pipeline.
+    """
+    authority = read_authority(ipod_path)
+    fields = authority.get("fields", {})
+    if not fields:
+        return False, {}
+
+    # Tamper detection — if SysInfo/SysInfoExtended were modified externally
+    # (by iTunes or another tool), we can't trust the cached provenance.
+    stored_hashes = authority.get("file_hashes", {})
+    if stored_hashes:
+        tampered = False
+        for label, path in [
+            ("SysInfo", _sysinfo_path(ipod_path)),
+            ("SysInfoExtended", _sysinfo_extended_path(ipod_path)),
+        ]:
+            stored = stored_hashes.get(label)
+            if stored is not None:
+                current = _hash_file(path)
+                if current != stored:
+                    tampered = True
+                    break
+        if tampered:
+            logger.info(
+                "Authority coverage: external modification detected, "
+                "treating all sources as low-authority",
+            )
+            return False, {}
+
+    field_sources: dict[str, str] = {}
+    all_tracked = True
+    for sysinfo_key, device_field in SYSINFO_FIELDS:
+        entry = fields.get(sysinfo_key)
+        if entry is None:
+            # Field not in authority at all.  Only core fields affect
+            # the "all tracked" flag — missing derived fields are fine
+            # (they'll be re-derived cheaply from model lookup).
+            if sysinfo_key in _CORE_FIELDS:
+                all_tracked = False
+            continue
+        source = entry.get("source", "unknown")
+        field_sources[device_field] = source
+
+    return all_tracked, field_sources
+
+
+# ──────────────────────────────────────────────────────────────────────
+# Formatting helpers
+# ──────────────────────────────────────────────────────────────────────
+
+def _format_for_sysinfo(sysinfo_key: str, device_value) -> str:
+    """Convert a DeviceInfo field value to the SysInfo on-disk format.
+
+    Handles both string and non-string field types (e.g. usb_pid is int).
+    """
+    if sysinfo_key == "USBProductID":
+        # usb_pid is an int on DeviceInfo
+        if isinstance(device_value, int):
+            return f"0x{device_value:04X}" if device_value else ""
+        # String passthrough (shouldn't happen, but safe)
+        return str(device_value) if device_value else ""
+    if not device_value:
+        return ""
+    device_value = str(device_value)
+    if sysinfo_key == "FirewireGuid":
+        clean = device_value
+        if clean.startswith(("0x", "0X")):
+            return f"0x{clean[2:].upper()}"
+        return f"0x{clean.upper()}"
+    if sysinfo_key == "ModelNumStr":
+        # SysInfo stores "xA623" — the 'M' prefix becomes 'x'
+        if device_value.startswith("M"):
+            return f"x{device_value[1:]}"
+        return device_value
+    return device_value
+
+
+def _normalise_sysinfo_value(sysinfo_key: str, raw_value) -> str:
+    """Normalise a raw SysInfo value to a comparable canonical form.
+
+    Strips null padding, ``0x`` prefixes, and whitespace so that
+    comparisons are not tripped up by trivial formatting differences.
+    """
+    val = str(raw_value).strip().rstrip("\x00")
+    if sysinfo_key == "FirewireGuid":
+        if val.startswith(("0x", "0X")):
+            val = val[2:]
+        return val.upper()
+    if sysinfo_key == "ModelNumStr":
+        if val.startswith("x"):
+            val = "M" + val[1:]
+        return val.upper().rstrip("\x00")
+    if sysinfo_key == "USBProductID":
+        if val.upper().startswith("0X"):
+            val = val[2:]
+        return val.upper().lstrip("0") or "0"
+    return val
+
+
+# ──────────────────────────────────────────────────────────────────────
+# File I/O
+# ──────────────────────────────────────────────────────────────────────
+
+def _authority_path(ipod_path: str) -> str:
+    return os.path.join(
+        ipod_path, "iPod_Control", "Device", AUTHORITY_FILENAME,
+    )
+
+
+def _sysinfo_path(ipod_path: str) -> str:
+    return os.path.join(ipod_path, "iPod_Control", "Device", "SysInfo")
+
+
+def _sysinfo_extended_path(ipod_path: str) -> str:
+    return os.path.join(ipod_path, "iPod_Control", "Device", "SysInfoExtended")
+
+
+def _hash_file(path: str) -> str | None:
+    """Return hex SHA-256 of a file, or ``None`` if the file is missing."""
+    if not os.path.exists(path):
+        return None
+    try:
+        h = hashlib.sha256()
+        with open(path, "rb") as f:
+            for chunk in iter(lambda: f.read(8192), b""):
+                h.update(chunk)
+        return h.hexdigest()
+    except Exception as exc:
+        logger.warning("Failed to hash %s: %s", path, exc)
+        return None
+
+
+def read_authority(ipod_path: str) -> dict:
+    """Read the authority file.  Returns ``{}`` if missing or corrupt."""
+    path = _authority_path(ipod_path)
+    if not os.path.exists(path):
+        return {}
+    try:
+        with open(path, encoding="utf-8") as f:
+            data = json.load(f)
+        if isinstance(data, dict):
+            return data
+    except Exception as exc:
+        logger.warning("Authority file read failed: %s", exc)
+    return {}
+
+
+def _write_authority(ipod_path: str, authority: dict) -> None:
+    path = _authority_path(ipod_path)
+    device_dir = os.path.dirname(path)
+    os.makedirs(device_dir, exist_ok=True)
+    try:
+        with open(path, "w", encoding="utf-8") as f:
+            json.dump(authority, f, indent=2, ensure_ascii=False)
+        logger.debug("Wrote authority file to %s", path)
+    except Exception as exc:
+        logger.warning("Failed to write authority file: %s", exc)
+
+
+def _read_sysinfo_raw(ipod_path: str) -> dict[str, str]:
+    """Read all key:value pairs from SysInfo, preserving raw values."""
+    path = _sysinfo_path(ipod_path)
+    result: dict[str, str] = {}
+    if not os.path.exists(path):
+        return result
+    try:
+        with open(path, errors="replace") as f:
+            for line in f:
+                if ":" in line:
+                    key, val = line.split(":", 1)
+                    result[key.strip()] = val.strip()
+    except Exception as exc:
+        logger.warning("SysInfo read failed: %s", exc)
+    return result
+
+
+def _write_sysinfo_file(ipod_path: str, fields: dict[str, str]) -> None:
+    """Write all fields to the SysInfo file."""
+    path = _sysinfo_path(ipod_path)
+    device_dir = os.path.dirname(path)
+    os.makedirs(device_dir, exist_ok=True)
+    lines = [f"{k}: {v}" for k, v in fields.items() if v]
+    try:
+        with open(path, "w", encoding="utf-8") as f:
+            f.write("\n".join(lines) + "\n")
+        logger.info("Wrote SysInfo (%d fields) to %s", len(lines), path)
+    except Exception as exc:
+        logger.warning("Failed to write SysInfo: %s", exc)
+
+
+def _normalise_sysinfo_extended(raw_xml: bytes | str) -> bytes:
+    """Return canonical SysInfoExtended plist bytes suitable for caching."""
+    if isinstance(raw_xml, str):
+        raw = raw_xml.encode("utf-8", errors="replace")
+    else:
+        raw = bytes(raw_xml or b"")
+    if not raw:
+        return b""
+
+    try:
+        from .sysinfo import parse_sysinfo_extended
+
+        parsed = parse_sysinfo_extended(raw)
+        if parsed.plist and parsed.raw_xml:
+            return parsed.raw_xml
+    except Exception:
+        pass
+
+    for marker in (b"<?xml", b"<plist"):
+        idx = raw.find(marker)
+        if idx >= 0:
+            raw = raw[idx:]
+            break
+    raw = raw.strip(b"\x00\r\n\t ")
+    if raw and b"</plist>" not in raw:
+        raw += b"\n</dict>\n</plist>"
+    return raw
+
+
+def cache_sysinfo_extended(
+    ipod_path: str,
+    raw_xml: bytes | str,
+    *,
+    source: str = "unknown",
+    metadata: dict | None = None,
+) -> bool:
+    """Cache a live SysInfoExtended payload and refresh authority hashes."""
+    if not ipod_path or not raw_xml:
+        return False
+
+    device_dir = os.path.join(ipod_path, "iPod_Control", "Device")
+    if not os.path.isdir(device_dir):
+        return False
+
+    data = _normalise_sysinfo_extended(raw_xml)
+    if not data:
+        return False
+
+    path = _sysinfo_extended_path(ipod_path)
+    try:
+        with open(path, "wb") as f:
+            f.write(data)
+    except Exception as exc:
+        logger.warning("Failed to cache SysInfoExtended: %s", exc)
+        return False
+
+    authority = read_authority(ipod_path)
+    now = datetime.now(UTC).isoformat()
+    files = authority.setdefault("files", {})
+    files["SysInfoExtended"] = {
+        "source": source,
+        "updated": now,
+        "bytes": len(data),
+    }
+    if metadata:
+        files["SysInfoExtended"]["metadata"] = {
+            str(k): v
+            for k, v in metadata.items()
+            if isinstance(v, (str, int, float, bool)) and v not in ("", None)
+        }
+    authority["version"] = 1
+    authority["last_updated"] = now
+    _store_file_hashes(ipod_path, authority)
+    _write_authority(ipod_path, authority)
+    logger.debug(
+        "Cached SysInfoExtended (%d bytes, source=%s) to %s",
+        len(data),
+        source,
+        path,
+    )
+    return True
+
+
+# ──────────────────────────────────────────────────────────────────────
+# Tamper detection
+# ──────────────────────────────────────────────────────────────────────
+
+def _detect_external_modification(
+    ipod_path: str,
+    authority: dict,
+    fields: dict[str, dict],
+    now: str,
+) -> None:
+    """Check whether SysInfo or SysInfoExtended were modified externally.
+
+    Compares the stored SHA-256 hashes in the authority file against the
+    current on-disk files.  If either file has been changed (e.g. by
+    iTunes or another tool), **all** authority source levels are reset to
+    ``"sysinfo"`` because we can no longer trust the provenance — the
+    external software may have overwritten fields with different values.
+    """
+    stored_hashes: dict[str, str] = authority.get("file_hashes", {})
+    if not stored_hashes:
+        # First run or no hashes recorded — nothing to compare.
+        return
+
+    tampered: list[str] = []
+
+    for label, path in [
+        ("SysInfo", _sysinfo_path(ipod_path)),
+        ("SysInfoExtended", _sysinfo_extended_path(ipod_path)),
+    ]:
+        stored = stored_hashes.get(label)
+        if stored is None:
+            # We never recorded a hash for this file — skip.
+            continue
+        current = _hash_file(path)
+        if current is None:
+            # File was deleted externally — that counts as a change.
+            tampered.append(f"{label} (deleted)")
+        elif current != stored:
+            tampered.append(label)
+
+    if not tampered:
+        return
+
+    logger.warning(
+        "External modification detected in %s — resetting all "
+        "authority sources to 'sysinfo'",
+        ", ".join(tampered),
+    )
+    for _sysinfo_key, entry in fields.items():
+        if isinstance(entry, dict) and entry.get("source") != "sysinfo":
+            entry["source"] = "sysinfo"
+            entry["updated"] = now
+
+
+def _store_file_hashes(ipod_path: str, authority: dict) -> None:
+    """Compute and store SHA-256 hashes of SysInfo and SysInfoExtended."""
+    hashes: dict[str, str] = {}
+    for label, path in [
+        ("SysInfo", _sysinfo_path(ipod_path)),
+        ("SysInfoExtended", _sysinfo_extended_path(ipod_path)),
+    ]:
+        h = _hash_file(path)
+        if h is not None:
+            hashes[label] = h
+    authority["file_hashes"] = hashes
+
+
+# ──────────────────────────────────────────────────────────────────────
+# Authority-aware SysInfo update
+# ──────────────────────────────────────────────────────────────────────
+
+def _rank(source: str) -> int:
+    """Lower = more reliable.  Unknown sources get worst rank."""
+    return SOURCE_RANK.get(source, _WORST_RANK)
+
+
+def _default_existing_source(sysinfo_key: str, old_raw: str) -> str:
+    """Return provenance for an existing SysInfo value with no authority entry."""
+    if not old_raw:
+        return "unknown"
+    if sysinfo_key in _DERIVED_SYSINFO_KEYS:
+        return "sysinfo"
+    return "itunes"
+
+
+def update_sysinfo(info: DeviceInfo) -> None:
+    """Reconcile gathered DeviceInfo with the on-disk SysInfo.
+
+    Called **after** all identification and enrichment is complete.
+
+    For each SysInfo-mappable field:
+
+    * Missing from SysInfo → add it.
+    * Same value → refresh authority timestamp (upgrade source if better).
+    * Different value → keep the one from the more reliable source.
+
+    Also writes/updates the ``iOpenPodSysInfoAuthority`` JSON alongside
+    SysInfo so future runs can make informed decisions.
+    """
+    if not info.path:
+        return
+
+    ipod_path = info.path
+    device_dir = os.path.join(ipod_path, "iPod_Control", "Device")
+    if not os.path.isdir(device_dir):
+        return
+
+    existing_sysinfo = _read_sysinfo_raw(ipod_path)
+    authority = read_authority(ipod_path)
+    fields = authority.get("fields", {})
+    now = datetime.now(UTC).isoformat()
+
+    # ── Tamper detection: hash SysInfo / SysInfoExtended ──────────
+    _detect_external_modification(ipod_path, authority, fields, now)
+
+    # Start with all existing SysInfo fields so we preserve any we don't map
+    updated_sysinfo: dict[str, str] = dict(existing_sysinfo)
+    sysinfo_changed = False
+
+    for sysinfo_key, device_field in SYSINFO_FIELDS:
+        new_value = getattr(info, device_field, "")
+
+        # Skip empty / default-sentinel values — these haven't been
+        # resolved to anything useful yet.
+        sentinel = _SENTINEL_DEFAULTS.get(device_field)
+        if sentinel is not None and new_value == sentinel:
+            continue
+        if not new_value:
+            continue
+
+        new_source: str = info._field_sources.get(device_field, "unknown")
+        new_formatted = _format_for_sysinfo(sysinfo_key, new_value)
+
+        old_raw = existing_sysinfo.get(sysinfo_key, "")
+        old_source: str = fields.get(sysinfo_key, {}).get(
+            "source", _default_existing_source(sysinfo_key, old_raw),
+        )
+
+        # ── Field missing from SysInfo → add it ──────────────────────
+        if not old_raw:
+            updated_sysinfo[sysinfo_key] = new_formatted
+            fields[sysinfo_key] = {
+                "value": new_formatted,
+                "source": new_source,
+                "updated": now,
+            }
+            sysinfo_changed = True
+            logger.debug(
+                "SysInfo: adding %s = %s (source: %s)",
+                sysinfo_key, new_formatted, new_source,
+            )
+            continue
+
+        # ── Compare normalised values ─────────────────────────────────
+        old_normalised = _normalise_sysinfo_value(sysinfo_key, old_raw)
+        new_normalised = _normalise_sysinfo_value(sysinfo_key, new_formatted)
+
+        if old_normalised == new_normalised:
+            # Same effective value — upgrade authority source if we're
+            # more (or equally) reliable, otherwise ensure the existing
+            # best source is still recorded (so authority coverage check
+            # sees the field as tracked).
+            best_source = (
+                new_source
+                if _rank(new_source) <= _rank(old_source)
+                else old_source
+            )
+            if sysinfo_key not in fields or _rank(best_source) <= _rank(
+                fields[sysinfo_key].get("source", "unknown"),
+            ):
+                fields[sysinfo_key] = {
+                    "value": old_raw,      # keep existing formatting
+                    "source": best_source,
+                    "updated": now,
+                }
+            continue
+
+        # iOpenPod-derived fields are cache material, not immutable iTunes
+        # facts.  If our current resolver produces a different derived label
+        # after a table/provenance fix, let it refresh stale authority entries
+        # even when the old cached source had a better historical rank.
+        if sysinfo_key in _DERIVED_SYSINFO_KEYS:
+            updated_sysinfo[sysinfo_key] = new_formatted
+            fields[sysinfo_key] = {
+                "value": new_formatted,
+                "source": new_source,
+                "updated": now,
+            }
+            sysinfo_changed = True
+            logger.debug(
+                "SysInfo: refreshing derived %s: %r → %r (source: %s)",
+                sysinfo_key,
+                old_raw,
+                new_formatted,
+                new_source,
+            )
+            continue
+
+        # ── Values differ — use the more reliable source ──────────────
+        if _rank(new_source) <= _rank(old_source):
+            # New source is at least as reliable → overwrite
+            updated_sysinfo[sysinfo_key] = new_formatted
+            fields[sysinfo_key] = {
+                "value": new_formatted,
+                "source": new_source,
+                "updated": now,
+            }
+            sysinfo_changed = True
+
+            logger.debug(
+                "SysInfo: updating %s: %r → %r (source %s [rank %d] "
+                "beats %s [rank %d])",
+                sysinfo_key, old_raw, new_formatted,
+                new_source, _rank(new_source),
+                old_source, _rank(old_source),
+            )
+        else:
+            # Existing value from a more reliable source → keep it
+            logger.debug(
+                "SysInfo: keeping %s = %r (source %s [rank %d] beats "
+                "new %s [rank %d] with %r)",
+                sysinfo_key, old_raw,
+                old_source, _rank(old_source),
+                new_source, _rank(new_source), new_formatted,
+            )
+
+    # ── Persist ───────────────────────────────────────────────────────
+    if sysinfo_changed:
+        _write_sysinfo_file(ipod_path, updated_sysinfo)
+
+    # Always ensure the authority dict is well-formed before writing.
+    authority["version"] = 1
+    authority["fields"] = fields
+    authority["last_updated"] = now
+
+    # Always refresh file hashes so the next run can detect tampering.
+    _store_file_hashes(ipod_path, authority)
+    _write_authority(ipod_path, authority)

src/vendor/ipod_device/capabilities.py

@@ -0,0 +1,641 @@
+"""Device capabilities — per-generation feature map backed by canonical artwork formats.
+
+Sources:
+  - libgpod ``itdb_device.c`` — itdb_device_supports_*() functions,
+    ipod_info_table, artwork format tables
+  - libgpod ``itdb_itunesdb.c`` — iTunesSD writer, mhbd version handling
+  - Empirical: iPod Classic 2G, Nano 3G confirmed
+
+This table captures every capability dimension that affects database
+writing, artwork generation, or sync behaviour.  It is the single
+authority for "what does this device support?" questions.
+"""
+
+from dataclasses import dataclass
+
+from .artwork_presets import (
+    ARTWORK_FORMATS_BY_ID,
+    CLASSIC_COVER_ART_FORMATS,
+    NANO_7G_COVER_ART_FORMATS,
+    ArtworkFormat,
+)
+from .checksum import ChecksumType
+
+
+@dataclass(frozen=True)
+class DeviceCapabilities:
+    """Per-generation device capability flags.
+
+    Every (family, generation) pair maps to exactly one of these.  The
+    flags drive decisions in the sync engine, iTunesDB writer, and
+    ArtworkDB writer.
+
+    All flags default to the *most common* value so that only deviations
+    need to be specified in the lookup table.
+    """
+
+    # ── Database format ────────────────────────────────────────────────
+    checksum: ChecksumType = ChecksumType.NONE
+    is_shuffle: bool = False
+    """If True, device uses iTunesSD (flat binary) instead of / in addition
+    to iTunesDB.  Shadow DB version determines the iTunesSD format."""
+    shadow_db_version: int = 0
+    """0 = not a shuffle.  1 = iTunesSD v1 (Shuffle 1G/2G, 18-byte header,
+    558-byte entries, big-endian).  2 = iTunesSD v2 (Shuffle 3G/4G,
+    bdhs/hths/hphs chunk format, little-endian)."""
+    supports_compressed_db: bool = False
+    """If True, device expects iTunesCDB (zlib-compressed iTunesDB) and will
+    generate an empty iTunesDB alongside it.  Nano 5G/6G/7G only."""
+
+    # ── Media type support ─────────────────────────────────────────────
+    supports_video: bool = False
+    """Device can play video files (mediatype & VIDEO != 0)."""
+    supports_podcast: bool = True
+    """Device supports podcast mhsd types (type 3).  False only for
+    very early iPods (1G–3G) and iPod Mobile."""
+    supports_gapless: bool = False
+    """Device honours gapless playback fields (pregap, postgap,
+    samplecount, gapless_data, gapless_track_flag).  Introduced with
+    iPod Video 5.5G (Late 2006)."""
+
+    # ── Artwork ────────────────────────────────────────────────────────
+    supports_artwork: bool = True
+    """Device has an ArtworkDB and .ithmb files for album art."""
+    supports_photo: bool = False
+    """Device has additional photo artwork formats (for photo viewer)."""
+    photo_formats: tuple[ArtworkFormat, ...] = ()
+    """Photo/slideshow ithmb formats used by the Photos database pipeline."""
+    supports_chapter_image: bool = False
+    """Device has chapter image artwork formats (for enhanced podcasts)."""
+    supports_sparse_artwork: bool = False
+    """Artwork can be written in sparse mode (Nano 3G+, Classic, Touch)."""
+    supports_alac: bool = True
+    """Device supports Apple Lossless (ALAC) audio playback.
+    False for iPod 1G–3G and Mini 1G (pre-firmware-update era hardware that
+    received ALAC support only from 4th Gen / Photo / Mini 2G onwards)."""
+    cover_art_formats: tuple[ArtworkFormat, ...] = ()
+    """Supported cover-art thumbnail sizes.  Empty means no artwork."""
+
+    # ── Storage layout ─────────────────────────────────────────────────
+    music_dirs: int = 20
+    """Number of ``Fxx`` directories under ``iPod_Control/Music/``.
+    Varies 0–50 depending on model and storage capacity."""
+
+    # ── SQLite database ────────────────────────────────────────────────
+    uses_sqlite_db: bool = False
+    """If True, device uses SQLite databases in
+    ``iTunes Library.itlp/`` instead of (or alongside) binary
+    iTunesDB/iTunesCDB.  The firmware on Nano 6G/7G reads the SQLite
+    databases and ignores iTunesCDB completely."""
+
+    # ── Writer parameters ──────────────────────────────────────────────
+    db_version: int = 0x30
+    """iTunesDB version to write in mhbd header.  Older iPods need
+    lower values (0x0c for Shuffle 1G/2G, 0x13 for pre-Classic)."""
+    byte_order: str = "le"
+    """Byte order for database writing.  ``"le"`` for almost all models.
+    ``"be"`` for iPod Mobile (Motorola ROKR/SLVR/RAZR)."""
+
+    # ── Screen / display ───────────────────────────────────────────────
+    has_screen: bool = True
+    """Device has a display.  Shuffles have no screen."""
+
+    # ── Video encoding limits ──────────────────────────────────────────
+    max_video_width: int = 0
+    """Maximum H.264 decode width (pixels).  0 = no video support.
+    This is the firmware decode ceiling, not the screen resolution —
+    the device downscales to fit its screen."""
+    max_video_height: int = 0
+    """Maximum H.264 decode height (pixels).  0 = no video support."""
+    max_video_fps: int = 30
+    """Maximum frame rate for H.264 decode (fps).  All video-capable iPods
+    support 30 fps; PAL-resolution Nano 7G content is typically 25 fps but
+    30 fps playback is still supported."""
+    max_video_bitrate: int = 0
+    """Hard bitrate ceiling for H.264 decode (kbps).  0 = no explicit cap
+    (quality-controlled by CRF only).  Non-zero values enforce a -maxrate
+    flag in ffmpeg.
+    Nano 3G/4G use Baseline Profile Level 1.3, capped at 768 kbps by spec."""
+    h264_level: str = "3.0"
+    """H.264 Baseline Profile level to target when encoding video.
+    Most iPods support Level 3.0.  iPod Classic supports 3.1.
+    Nano 3G/4G are limited to Level 1.3 by their hardware decoder."""
+
+
+# ──────────────────────────────────────────────────────────────────────────
+# The master capabilities table
+# ──────────────────────────────────────────────────────────────────────────
+
+_FAMILY_GEN_CAPABILITIES: dict[tuple[str, str], DeviceCapabilities] = {
+
+    # ── iPod 1G–3G: earliest models, no podcast, no gapless ───────────
+    ("iPod", "1st Gen"): DeviceCapabilities(
+        supports_podcast=False,
+        supports_artwork=False,
+        supports_alac=True,
+        has_screen=True,
+        music_dirs=20,
+        db_version=0x13,
+    ),
+    ("iPod", "2nd Gen"): DeviceCapabilities(
+        supports_podcast=False,
+        supports_artwork=False,
+        supports_alac=True,
+        has_screen=True,
+        music_dirs=20,
+        db_version=0x13,
+    ),
+    ("iPod", "3rd Gen"): DeviceCapabilities(
+        supports_podcast=False,
+        supports_artwork=False,
+        supports_alac=True,
+        has_screen=True,
+        music_dirs=20,
+        db_version=0x13,
+    ),
+
+    # ── iPod 4G (Click Wheel): first with podcast support ─────────────
+    ("iPod", "4th Gen"): DeviceCapabilities(
+        supports_artwork=False,
+        music_dirs=20,
+        db_version=0x13,
+    ),
+
+    # ── iPod U2 Special Edition (4th Gen hardware) ────────────────────
+    ("iPod U2", "4th Gen"): DeviceCapabilities(
+        supports_artwork=False,
+        music_dirs=20,
+        db_version=0x13,
+    ),
+
+    # ── iPod Photo (Color Display) ────────────────────────────────────
+    ("iPod Photo", "4th Gen"): DeviceCapabilities(
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1009],
+            ARTWORK_FORMATS_BY_ID[1013],
+            ARTWORK_FORMATS_BY_ID[1015],
+            ARTWORK_FORMATS_BY_ID[1019],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1017],
+            ARTWORK_FORMATS_BY_ID[1016],
+        ),
+        music_dirs=20,
+        db_version=0x13,
+    ),
+
+    # ── iPod Video 5th Gen ────────────────────────────────────────────
+    ("iPod Video", "5th Gen"): DeviceCapabilities(
+        supports_video=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1036],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1015],
+            ARTWORK_FORMATS_BY_ID[1019],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1028],
+            ARTWORK_FORMATS_BY_ID[1029],
+        ),
+        music_dirs=20,
+        db_version=0x19,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+
+    # ── iPod Video 5.5th Gen — first with gapless playback ───────────
+    ("iPod Video", "5.5th Gen"): DeviceCapabilities(
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1036],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1015],
+            ARTWORK_FORMATS_BY_ID[1019],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1028],
+            ARTWORK_FORMATS_BY_ID[1029],
+        ),
+        music_dirs=20,
+        db_version=0x19,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+
+    # ── iPod Video U2 editions ────────────────────────────────────────
+    ("iPod Video U2", "5th Gen"): DeviceCapabilities(
+        supports_video=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1036],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1015],
+            ARTWORK_FORMATS_BY_ID[1019],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1028],
+            ARTWORK_FORMATS_BY_ID[1029],
+        ),
+        music_dirs=20,
+        db_version=0x19,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+    ("iPod Video U2", "5.5th Gen"): DeviceCapabilities(
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1036],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1015],
+            ARTWORK_FORMATS_BY_ID[1019],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1028],
+            ARTWORK_FORMATS_BY_ID[1029],
+        ),
+        music_dirs=20,
+        db_version=0x19,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+
+    # ── iPod Classic (all gens): HASH58, gapless, video ───────────────
+    ("iPod Classic", "1st Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASH58,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1067],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1066],
+        ),
+        supports_chapter_image=True,
+        supports_sparse_artwork=True,
+        cover_art_formats=CLASSIC_COVER_ART_FORMATS,
+        music_dirs=50,
+        db_version=0x30,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+    ("iPod Classic", "2nd Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASH58,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1067],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1066],
+        ),
+        supports_chapter_image=True,
+        supports_sparse_artwork=True,
+        cover_art_formats=CLASSIC_COVER_ART_FORMATS,
+        music_dirs=50,
+        db_version=0x30,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+    ("iPod Classic", "3rd Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASH58,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1067],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1066],
+        ),
+        supports_chapter_image=True,
+        supports_sparse_artwork=True,
+        cover_art_formats=CLASSIC_COVER_ART_FORMATS,
+        music_dirs=50,
+        db_version=0x30,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+
+    # ── iPod Mini ─────────────────────────────────────────────────────
+    ("iPod Mini", "1st Gen"): DeviceCapabilities(
+        supports_artwork=False,
+        supports_alac=True,
+        music_dirs=6,
+        db_version=0x13,
+    ),
+    ("iPod Mini", "2nd Gen"): DeviceCapabilities(
+        supports_artwork=False,
+        music_dirs=6,
+        db_version=0x13,
+    ),
+
+    # ── iPod Nano 1G/2G ──────────────────────────────────────────────
+    ("iPod Nano", "1st Gen"): DeviceCapabilities(
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1032],
+            ARTWORK_FORMATS_BY_ID[1023],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1031],
+            ARTWORK_FORMATS_BY_ID[1027],
+        ),
+        music_dirs=14,
+        db_version=0x13,
+    ),
+    ("iPod Nano", "2nd Gen"): DeviceCapabilities(
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1032],
+            ARTWORK_FORMATS_BY_ID[1023],
+        ),
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1031],
+            ARTWORK_FORMATS_BY_ID[1027],
+        ),
+        music_dirs=14,
+        db_version=0x13,
+    ),
+
+    # ── iPod Nano 3G ("Fat"): first Nano with video, HASH58 ──────────
+    ("iPod Nano", "3rd Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASH58,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1067],
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1066],
+        ),
+        supports_sparse_artwork=True,
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1061],
+            ARTWORK_FORMATS_BY_ID[1055],
+            ARTWORK_FORMATS_BY_ID[1068],
+            ARTWORK_FORMATS_BY_ID[1060],
+        ),
+        music_dirs=20,
+        db_version=0x30,
+        max_video_width=320,
+        max_video_height=240,
+        max_video_bitrate=768,
+        h264_level="1.3",
+    ),
+
+    # ── iPod Nano 4G: HASH58 ─────────────────────────────────────────
+    ("iPod Nano", "4th Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASH58,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1024],
+            ARTWORK_FORMATS_BY_ID[1066],
+            ARTWORK_FORMATS_BY_ID[1079],
+            ARTWORK_FORMATS_BY_ID[1083],
+        ),
+        supports_chapter_image=True,
+        supports_sparse_artwork=True,
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1055],
+            ARTWORK_FORMATS_BY_ID[1068],
+            ARTWORK_FORMATS_BY_ID[1071],
+            ARTWORK_FORMATS_BY_ID[1074],
+            ARTWORK_FORMATS_BY_ID[1078],
+            ARTWORK_FORMATS_BY_ID[1084],
+        ),
+        music_dirs=20,
+        db_version=0x30,
+        max_video_width=480,
+        max_video_height=320,
+        max_video_bitrate=768,
+        h264_level="1.3",
+    ),
+
+    # ── iPod Nano 5G: HASH72, compressed DB + SQLite ─────────────────
+    ("iPod Nano", "5th Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASH72,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1087],
+            ARTWORK_FORMATS_BY_ID[1079],
+            ARTWORK_FORMATS_BY_ID[1066],
+        ),
+        supports_sparse_artwork=True,
+        supports_compressed_db=True,
+        uses_sqlite_db=True,
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1056],
+            ARTWORK_FORMATS_BY_ID[1078],
+            ARTWORK_FORMATS_BY_ID[1073],
+            ARTWORK_FORMATS_BY_ID[1074],
+        ),
+        music_dirs=14,
+        db_version=0x30,
+        max_video_width=640,
+        max_video_height=480,
+    ),
+
+    # ── iPod Nano 6G: HASHAB, no video ───────────────────────────────
+    ("iPod Nano", "6th Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASHAB,
+        supports_video=False,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1092],
+            ARTWORK_FORMATS_BY_ID[1093],
+        ),
+        supports_sparse_artwork=True,
+        supports_compressed_db=True,
+        uses_sqlite_db=True,
+        cover_art_formats=(
+            ARTWORK_FORMATS_BY_ID[1073],
+            ARTWORK_FORMATS_BY_ID[1085],
+            ARTWORK_FORMATS_BY_ID[1089],
+            ARTWORK_FORMATS_BY_ID[1074],
+        ),
+        music_dirs=20,
+        db_version=0x30,
+    ),
+
+    # ── iPod Nano 7G: HASHAB, video returns ──────────────────────────
+    ("iPod Nano", "7th Gen"): DeviceCapabilities(
+        checksum=ChecksumType.HASHAB,
+        supports_video=True,
+        supports_gapless=True,
+        supports_artwork=True,
+        supports_photo=True,
+        photo_formats=(
+            ARTWORK_FORMATS_BY_ID[1007],
+            ARTWORK_FORMATS_BY_ID[1005],
+        ),
+        supports_sparse_artwork=True,
+        supports_compressed_db=True,
+        uses_sqlite_db=True,
+        cover_art_formats=NANO_7G_COVER_ART_FORMATS,
+        music_dirs=20,
+        db_version=0x30,
+        max_video_width=720,
+        max_video_height=576,
+    ),
+
+    # ── iPod Shuffle 1G ──────────────────────────────────────────────
+    ("iPod Shuffle", "1st Gen"): DeviceCapabilities(
+        is_shuffle=True,
+        shadow_db_version=1,
+        supports_podcast=True,
+        supports_artwork=False,
+        has_screen=False,
+        music_dirs=3,
+        db_version=0x0c,
+    ),
+
+    # ── iPod Shuffle 2G ──────────────────────────────────────────────
+    ("iPod Shuffle", "2nd Gen"): DeviceCapabilities(
+        is_shuffle=True,
+        shadow_db_version=1,
+        supports_podcast=True,
+        supports_artwork=False,
+        has_screen=False,
+        music_dirs=3,
+        db_version=0x13,
+    ),
+
+    # ── iPod Shuffle 3G ──────────────────────────────────────────────
+    ("iPod Shuffle", "3rd Gen"): DeviceCapabilities(
+        is_shuffle=True,
+        shadow_db_version=2,
+        supports_podcast=True,
+        supports_artwork=False,
+        has_screen=False,
+        music_dirs=3,
+        db_version=0x19,
+    ),
+
+    # ── iPod Shuffle 4G ──────────────────────────────────────────────
+    ("iPod Shuffle", "4th Gen"): DeviceCapabilities(
+        is_shuffle=True,
+        shadow_db_version=2,
+        supports_podcast=True,
+        supports_artwork=False,
+        has_screen=False,
+        music_dirs=3,
+        db_version=0x19,
+    ),
+}
+
+
+def capabilities_for_family_gen(
+    family: str,
+    generation: str,
+    *,
+    capacity: str | None = None,
+    model_number: str | None = None,
+) -> DeviceCapabilities | None:
+    """Return the device capabilities for a (family, generation) pair.
+
+    If the exact pair is not found but *generation* is empty/unknown,
+    checks whether all known generations of *family* share identical
+    capabilities and returns those.
+
+    Returns ``None`` if the pair is not in the lookup table and the
+    family-level fallback is ambiguous.
+    """
+    caps = _FAMILY_GEN_CAPABILITIES.get((family, generation))
+    if caps is not None:
+        return caps
+
+    if family and not generation:
+        family_caps = [
+            c for (f, _g), c in _FAMILY_GEN_CAPABILITIES.items()
+            if f == family
+        ]
+        if family_caps and all(c == family_caps[0] for c in family_caps):
+            return family_caps[0]
+
+    return None
+
+
+def cover_art_formats_for_family_gen(
+    family: str,
+    generation: str,
+    *,
+    capacity: str | None = None,
+    model_number: str | None = None,
+) -> tuple[ArtworkFormat, ...]:
+    """Return cover-art formats for a family/generation pair.
+
+    This is intentionally narrower than ``capabilities_for_family_gen``. Some
+    families have generations with different playback capabilities but the same
+    ArtworkDB cover formats, so a full capability fallback would be ambiguous
+    while artwork generation is still safe.
+    """
+    _ = capacity, model_number
+
+    caps = _FAMILY_GEN_CAPABILITIES.get((family, generation))
+    if caps is not None:
+        return caps.cover_art_formats if caps.supports_artwork else ()
+
+    if family and not generation:
+        family_formats = [
+            c.cover_art_formats if c.supports_artwork else ()
+            for (f, _g), c in _FAMILY_GEN_CAPABILITIES.items()
+            if f == family
+        ]
+        if family_formats and all(formats == family_formats[0] for formats in family_formats):
+            return family_formats[0]
+
+    return ()
+
+
+def checksum_type_for_family_gen(
+    family: str,
+    generation: str,
+) -> ChecksumType | None:
+    """Return the checksum type for a (family, generation) pair.
+
+    Derives the answer from ``_FAMILY_GEN_CAPABILITIES``.  If the exact
+    (family, generation) pair is not found but *generation* is empty/unknown,
+    checks whether all known generations of *family* share the same checksum
+    type and returns it.
+
+    Returns ``None`` if the pair is not in the lookup table and the family-
+    level fallback is ambiguous.
+    """
+    caps = _FAMILY_GEN_CAPABILITIES.get((family, generation))
+    if caps is not None:
+        return caps.checksum
+
+    if family and not generation:
+        family_checksums = {
+            c.checksum
+            for (f, _g), c in _FAMILY_GEN_CAPABILITIES.items()
+            if f == family
+        }
+        if len(family_checksums) == 1:
+            return family_checksums.pop()
+
+    return None

src/vendor/ipod_device/checksum.py

@@ -0,0 +1,41 @@
+"""Checksum type enumeration and MHBD hashing-scheme mappings."""
+
+from enum import IntEnum
+
+
+class ChecksumType(IntEnum):
+    """Checksum types for different iPod generations.
+
+    NONE        — Pre-2007 iPods (1G–5G, Photo, Video, Mini, Nano 1G–2G, Shuffle)
+    HASH58      — iPod Classic (all gens), Nano 3G, Nano 4G
+    HASH72      — Nano 5G
+    HASHAB      — Nano 6G, Nano 7G (white-box AES, via WASM module)
+    UNSUPPORTED — Reserved for any future unsupported scheme
+    UNKNOWN     — Device not yet identified
+    """
+    NONE = 0
+    HASH58 = 1
+    HASH72 = 2
+    HASHAB = 3
+    UNSUPPORTED = 98
+    UNKNOWN = 99
+
+
+# ── MHBD hashing scheme ↔ ChecksumType mapping ──────────────────────────
+#
+# The mhbd header at offset 0x30 stores a 16-bit ``hashing_scheme`` value.
+# These constants map between our ``ChecksumType`` enum and the raw wire
+# values.  Note: HASHAB is enum 3 but wire 4.
+
+CHECKSUM_MHBD_SCHEME: dict[ChecksumType, int] = {
+    ChecksumType.NONE: 0,
+    ChecksumType.HASH58: 1,
+    ChecksumType.HASH72: 2,
+    ChecksumType.HASHAB: 4,
+}
+"""Map ``ChecksumType`` → raw ``hashing_scheme`` field in mhbd header."""
+
+MHBD_SCHEME_TO_CHECKSUM: dict[int, ChecksumType] = {
+    v: k for k, v in CHECKSUM_MHBD_SCHEME.items()
+}
+"""Map raw ``hashing_scheme`` field in mhbd header → ``ChecksumType``."""

src/vendor/ipod_device/diagnostic_log.py

@@ -0,0 +1,177 @@
+"""Compact log formatting helpers for device-identification diagnostics."""
+
+from __future__ import annotations
+
+from collections.abc import Iterable, Mapping
+from typing import Any
+
+FieldSpec = tuple[str, str]
+
+
+IDENTITY_FIELDS: tuple[FieldSpec, ...] = (
+    ("model_number", "model"),
+    ("model_family", "family"),
+    ("generation", "gen"),
+    ("capacity", "capacity"),
+    ("color", "color"),
+    ("serial", "serial"),
+    ("firewire_guid", "fwguid"),
+    ("firmware", "fw"),
+    ("usb_vid", "vid"),
+    ("usb_pid", "pid"),
+    ("usb_serial", "usb_serial"),
+    ("scsi_vendor", "scsi_vendor"),
+    ("scsi_product", "scsi_product"),
+    ("scsi_revision", "scsi_rev"),
+)
+
+CAPABILITY_FIELDS: tuple[FieldSpec, ...] = (
+    ("family_id", "family_id"),
+    ("updater_family_id", "updater_id"),
+    ("product_type", "product"),
+    ("db_version", "db_version"),
+    ("shadow_db_version", "shadow_db"),
+    ("uses_sqlite_db", "sqlite"),
+    ("supports_sparse_artwork", "sparse_art"),
+    ("max_tracks", "max_tracks"),
+    ("max_file_size_gb", "max_file_gb"),
+    ("max_transfer_speed", "max_transfer"),
+    ("podcasts_supported", "podcasts"),
+    ("voice_memos_supported", "voice_memos"),
+    ("artwork_formats", "art_ids"),
+    ("photo_formats", "photo_ids"),
+    ("chapter_image_formats", "chapter_ids"),
+)
+
+SOURCE_FIELDS: tuple[FieldSpec, ...] = (
+    ("serial", "serial"),
+    ("firewire_guid", "fwguid"),
+    ("model_number", "model"),
+    ("model_family", "family"),
+    ("generation", "gen"),
+    ("capacity", "capacity"),
+    ("color", "color"),
+    ("usb_pid", "pid"),
+    ("firmware", "fw"),
+)
+
+_HEX_WIDTHS: dict[str, int] = {
+    "usb_vid": 4,
+    "usb_pid": 4,
+    "db_version": 0,
+    "shadow_db_version": 0,
+}
+
+
+def is_missing(value: Any) -> bool:
+    return value is None or value == "" or value == b"" or value == {} or value == []
+
+
+def compact(value: Any, *, max_chars: int = 96) -> str:
+    text = str(value)
+    if len(text) <= max_chars:
+        return text
+    head = max_chars // 2 - 2
+    tail = max_chars - head - 3
+    return f"{text[:head]}...{text[-tail:]}"
+
+
+def format_value(field: str, value: Any) -> str:
+    if isinstance(value, bytes):
+        return f"<{len(value)} bytes>"
+    if isinstance(value, bool):
+        return "yes" if value else "no"
+    if field in _HEX_WIDTHS:
+        try:
+            number = int(value)
+            if not number:
+                return "0"
+            width = _HEX_WIDTHS[field]
+            return f"0x{number:0{width}X}" if width else f"0x{number:X}"
+        except (TypeError, ValueError):
+            return compact(value)
+    if isinstance(value, Mapping):
+        if field.endswith("_formats") or field in {
+            "artwork_formats",
+            "photo_formats",
+            "chapter_image_formats",
+        }:
+            ids = ", ".join(str(k) for k in sorted(value)[:12])
+            suffix = "..." if len(value) > 12 else ""
+            return f"{len(value)}[{ids}{suffix}]"
+        keys = ", ".join(str(k) for k in sorted(value, key=str)[:8])
+        suffix = "..." if len(value) > 8 else ""
+        return f"{len(value)} keys[{keys}{suffix}]"
+    if isinstance(value, Iterable) and not isinstance(value, (str, bytes)):
+        items = list(value)
+        shown = ", ".join(str(item) for item in items[:12])
+        suffix = "..." if len(items) > 12 else ""
+        return f"{len(items)}[{shown}{suffix}]"
+    return compact(value)
+
+
+def format_fields(
+    data: Mapping[str, Any],
+    fields: Iterable[FieldSpec] = IDENTITY_FIELDS,
+    *,
+    include_false: bool = False,
+) -> str:
+    parts: list[str] = []
+    for field, label in fields:
+        if field not in data:
+            continue
+        value = data.get(field)
+        if is_missing(value):
+            continue
+        if value == 0 and not isinstance(value, bool):
+            continue
+        if value is False and not include_false:
+            continue
+        parts.append(f"{label}={format_value(field, value)}")
+    return ", ".join(parts) if parts else "none"
+
+
+def format_sources(
+    sources: Mapping[str, Any] | None,
+    fields: Iterable[FieldSpec] = SOURCE_FIELDS,
+) -> str:
+    if not sources:
+        return "none"
+    parts = []
+    for field, label in fields:
+        source = sources.get(field)
+        if source:
+            parts.append(f"{label}:{source}")
+    return ", ".join(parts) if parts else "none"
+
+
+def format_conflicts(conflicts: Any) -> str:
+    if not conflicts:
+        return "none"
+    if not isinstance(conflicts, list):
+        return compact(conflicts)
+
+    parts: list[str] = []
+    for conflict in conflicts[:6]:
+        if isinstance(conflict, Mapping):
+            field = conflict.get("field", "?")
+            winner = conflict.get("winner", "")
+            rejected_source = conflict.get("rejected_source", "")
+            rejected_value = conflict.get("rejected_value", "")
+            reason = conflict.get("reason", "")
+            detail = f"{field}"
+            if winner:
+                detail += f" winner={winner}"
+            if rejected_source or rejected_value:
+                detail += (
+                    f" rejected={rejected_source or '?'}:"
+                    f"{compact(rejected_value, max_chars=36)}"
+                )
+            if reason:
+                detail += f" reason={compact(reason, max_chars=64)}"
+            parts.append(detail)
+        else:
+            parts.append(compact(conflict, max_chars=96))
+    if len(conflicts) > 6:
+        parts.append(f"+{len(conflicts) - 6} more")
+    return "; ".join(parts)

src/vendor/ipod_device/dump.py

@@ -0,0 +1,495 @@
+"""Read-only diagnostic dump for connected iPods.
+
+Usage:
+    uv run python -m ipod_device.dump D:\
+    uv run python -m ipod_device.dump --all
+"""
+
+from __future__ import annotations
+
+import argparse
+import hashlib
+import json
+import os
+import sys
+from pathlib import Path
+from typing import Any
+
+IDENTITY_FIELDS: tuple[str, ...] = (
+    "serial",
+    "firewire_guid",
+    "model_number",
+    "model_family",
+    "generation",
+    "capacity",
+    "color",
+    "firmware",
+    "board",
+    "family_id",
+    "updater_family_id",
+    "product_type",
+    "usb_vid",
+    "usb_pid",
+    "usb_serial",
+    "scsi_vendor",
+    "scsi_product",
+    "scsi_revision",
+    "connected_bus",
+    "volume_format",
+    "db_version",
+    "shadow_db_version",
+    "uses_sqlite_db",
+    "supports_sparse_artwork",
+    "max_tracks",
+    "max_file_size_gb",
+    "max_transfer_speed",
+    "podcasts_supported",
+    "voice_memos_supported",
+)
+
+
+def _device_dir(mount_path: str) -> Path:
+    return Path(mount_path) / "iPod_Control" / "Device"
+
+
+def _mount_name(mount_path: str) -> str:
+    if sys.platform == "win32":
+        drive, _tail = os.path.splitdrive(mount_path)
+        if drive:
+            return drive
+        if mount_path and mount_path[0].isalpha():
+            return f"{mount_path[0].upper()}:"
+    return os.path.basename(os.path.normpath(mount_path)) or mount_path
+
+
+def _normalise_mount_path(mount_path: str) -> str:
+    if sys.platform == "win32":
+        stripped = mount_path.strip().strip('"')
+        if len(stripped) == 2 and stripped[0].isalpha() and stripped[1] == ":":
+            return stripped + "\\"
+        return stripped
+    return mount_path
+
+
+def _sha256(data: bytes) -> str:
+    return hashlib.sha256(data).hexdigest()
+
+
+def _json_safe(value: Any, *, include_raw: bool = False) -> Any:
+    if isinstance(value, bytes):
+        result: dict[str, Any] = {
+            "bytes": len(value),
+            "sha256": _sha256(value),
+        }
+        if include_raw:
+            result["text"] = value.decode("utf-8", errors="replace")
+        return result
+    if isinstance(value, dict):
+        return {
+            str(k): _json_safe(v, include_raw=include_raw)
+            for k, v in sorted(value.items(), key=lambda item: str(item[0]))
+        }
+    if isinstance(value, (list, tuple)):
+        return [_json_safe(v, include_raw=include_raw) for v in value]
+    return value
+
+
+def _normalise_for_compare(field: str, value: Any) -> str:
+    if value in (None, ""):
+        return ""
+    if field == "firewire_guid":
+        try:
+            from .sysinfo import normalize_guid
+
+            return normalize_guid(value)
+        except Exception:
+            pass
+    if field == "usb_pid":
+        try:
+            return f"0x{int(value):04X}"
+        except Exception:
+            return str(value).strip().upper()
+    return str(value).strip()
+
+
+def _sysinfo_dump(mount_path: str) -> dict[str, Any]:
+    path = _device_dir(mount_path) / "SysInfo"
+    if not path.exists():
+        return {"present": False}
+
+    raw = path.read_text(errors="replace")
+    from .sysinfo import identity_from_sysinfo, parse_sysinfo_text
+
+    parsed = parse_sysinfo_text(raw)
+    return {
+        "present": True,
+        "path": str(path),
+        "sha256": _sha256(raw.encode("utf-8", errors="replace")),
+        "fields": parsed,
+        "identity": identity_from_sysinfo(parsed, "sysinfo"),
+    }
+
+
+def _sysinfo_extended_dump(
+    mount_path: str,
+    *,
+    include_raw: bool,
+) -> dict[str, Any]:
+    path = _device_dir(mount_path) / "SysInfoExtended"
+    if not path.exists():
+        return {"present": False}
+
+    raw = path.read_bytes()
+    from .sysinfo import parse_sysinfo_extended
+
+    parsed = parse_sysinfo_extended(raw, source="sysinfo_extended")
+    result: dict[str, Any] = {
+        "present": True,
+        "path": str(path),
+        "bytes": len(raw),
+        "sha256": _sha256(raw),
+        "used_regex_fallback": parsed.used_regex_fallback,
+        "keys": sorted(parsed.plist.keys()),
+        "identity": parsed.identity,
+        "cover_art_formats": parsed.cover_art_formats,
+        "photo_formats": parsed.photo_formats,
+        "chapter_image_formats": parsed.chapter_image_formats,
+    }
+    if include_raw:
+        result["raw"] = raw
+        result["plist"] = parsed.plist
+    return result
+
+
+def _identity_from_live_vpd(vpd: dict[str, Any], source: str) -> dict[str, Any]:
+    from .sysinfo import (
+        ParsedSysInfoExtended,
+        identity_from_sysinfo_extended,
+        parse_sysinfo_extended,
+    )
+
+    raw = vpd.get("vpd_raw_xml")
+    if raw:
+        identity = parse_sysinfo_extended(raw, source=source, live=True).identity
+    else:
+        parsed = ParsedSysInfoExtended(plist=vpd, source=source, live=True)
+        identity = identity_from_sysinfo_extended(parsed, source, live=True)
+    sources = identity.setdefault("_sources", {})
+    for field in (
+        "usb_pid",
+        "usb_vid",
+        "usb_serial",
+        "scsi_vendor",
+        "scsi_product",
+        "scsi_revision",
+        "block_device",
+    ):
+        value = vpd.get(field)
+        if value not in (None, "", b""):
+            identity[field] = value
+            sources[field] = source
+    return identity
+
+
+def _live_scsi_dump(
+    mount_path: str,
+    final_identity: dict[str, Any],
+) -> dict[str, Any]:
+    try:
+        if sys.platform == "win32":
+            from .vpd_windows import query_ipod_vpd_for_path
+
+            result = query_ipod_vpd_for_path(
+                mount_path,
+                usb_pid=int(final_identity.get("usb_pid") or 0),
+                serial_filter=str(final_identity.get("firewire_guid") or ""),
+            )
+        elif sys.platform == "linux":
+            from .vpd_linux import query_ipod_vpd_for_path
+
+            result = query_ipod_vpd_for_path(
+                mount_path,
+                usb_pid=int(final_identity.get("usb_pid") or 0),
+                serial_filter=str(final_identity.get("firewire_guid") or ""),
+            )
+        elif sys.platform == "darwin":
+            from .vpd_iokit import query_ipod_vpd
+
+            result = query_ipod_vpd(
+                usb_pid=int(final_identity.get("usb_pid") or 0),
+                serial_filter=str(final_identity.get("firewire_guid") or ""),
+            )
+        else:
+            return {"available": False, "reason": f"unsupported_{sys.platform}"}
+        if not result:
+            return {"available": True, "result": None, "error": "no_result"}
+        source = str(result.get("_source") or {
+            "win32": "windows_scsi",
+            "linux": "linux_scsi",
+            "darwin": "scsi_vpd",
+        }.get(sys.platform, "scsi_vpd"))
+        return {
+            "available": True,
+            "result": result,
+            "identity": _identity_from_live_vpd(result, source),
+            "standard_inquiry": {
+                "vendor": result.get("scsi_vendor", ""),
+                "product": result.get("scsi_product", ""),
+                "revision": result.get("scsi_revision", ""),
+            },
+        }
+    except Exception as exc:
+        return {"available": True, "result": None, "error": repr(exc)}
+
+
+def _live_windows_scsi_dump(
+    mount_path: str,
+    final_identity: dict[str, Any],
+) -> dict[str, Any]:
+    if sys.platform != "win32":
+        return {"available": False, "reason": "not_windows"}
+    return _live_scsi_dump(mount_path, final_identity)
+
+
+def _live_usb_vendor_dump(
+    final_identity: dict[str, Any],
+) -> dict[str, Any]:
+    try:
+        from .usb_backend import backend_diagnostic
+        from .vpd_usb_control import query_ipod_usb_sysinfo_extended
+
+        result = query_ipod_usb_sysinfo_extended(
+            usb_pid=int(final_identity.get("usb_pid") or 0),
+            serial_filter=str(final_identity.get("firewire_guid") or ""),
+        )
+        if not result:
+            return {
+                "available": True,
+                "result": None,
+                "error": "no_result",
+                "backend": backend_diagnostic(),
+            }
+        source = str(result.get("_source") or "usb_vendor")
+        return {
+            "available": True,
+            "result": result,
+            "identity": _identity_from_live_vpd(result, source),
+            "backend": backend_diagnostic(),
+        }
+    except Exception as exc:
+        return {"available": False, "result": None, "error": repr(exc)}
+
+
+def _disk_size_gb(mount_path: str) -> float:
+    try:
+        import shutil
+
+        return round(shutil.disk_usage(mount_path).total / 1e9, 1)
+    except Exception:
+        return 0.0
+
+
+def _final_identity_snapshot(mount_path: str) -> dict[str, Any]:
+    from .scanner import _probe_filesystem, _probe_hardware, _resolve_model
+
+    mount_name = _mount_name(mount_path)
+    hardware = _probe_hardware(mount_path, mount_name)
+    filesystem = _probe_filesystem(mount_path)
+    resolved = _resolve_model(hardware, filesystem, _disk_size_gb(mount_path))
+    return {
+        "hardware": hardware,
+        "filesystem": filesystem,
+        "resolved": resolved,
+    }
+
+
+def _append_identity_evidence(
+    evidence: dict[str, list[dict[str, Any]]],
+    source: str,
+    identity: dict[str, Any] | None,
+) -> None:
+    if not identity:
+        return
+    sources = identity.get("_sources", {})
+    for field in IDENTITY_FIELDS:
+        value = identity.get(field)
+        if value in (None, ""):
+            continue
+        evidence.setdefault(field, []).append({
+            "source": sources.get(field, source),
+            "value": value,
+        })
+
+
+def _append_plain_evidence(
+    evidence: dict[str, list[dict[str, Any]]],
+    source: str,
+    data: dict[str, Any] | None,
+) -> None:
+    if not data:
+        return
+    sources = data.get("_sources", {})
+    for field in IDENTITY_FIELDS:
+        value = data.get(field)
+        if value in (None, ""):
+            continue
+        evidence.setdefault(field, []).append({
+            "source": sources.get(field, source),
+            "value": value,
+        })
+
+
+def _rejected_conflicts(
+    final_identity: dict[str, Any],
+    evidence: dict[str, list[dict[str, Any]]],
+) -> list[dict[str, Any]]:
+    rejected: list[dict[str, Any]] = []
+    for field, entries in sorted(evidence.items()):
+        final_value = final_identity.get(field)
+        final_norm = _normalise_for_compare(field, final_value)
+        if not final_norm:
+            continue
+        for entry in entries:
+            value_norm = _normalise_for_compare(field, entry.get("value"))
+            if value_norm and value_norm != final_norm:
+                rejected.append({
+                    "field": field,
+                    "final_value": final_value,
+                    "rejected_value": entry.get("value"),
+                    "rejected_source": entry.get("source"),
+                })
+    return rejected
+
+
+def dump_device_info(
+    mount_path: str,
+    *,
+    include_raw: bool = False,
+    probe_usb_vendor: bool = True,
+) -> dict[str, Any]:
+    """Build a read-only device diagnostic report."""
+    mount_path = os.path.abspath(_normalise_mount_path(mount_path))
+    snapshot = _final_identity_snapshot(mount_path)
+    final_identity = snapshot["resolved"]
+
+    sysinfo = _sysinfo_dump(mount_path)
+    sysinfo_extended = _sysinfo_extended_dump(
+        mount_path,
+        include_raw=include_raw,
+    )
+    live_scsi = _live_scsi_dump(mount_path, final_identity)
+    live_windows_scsi = (
+        live_scsi
+        if sys.platform == "win32"
+        else {"available": False, "reason": "not_windows"}
+    )
+    live_usb_vendor = (
+        _live_usb_vendor_dump(final_identity)
+        if probe_usb_vendor
+        else {"available": False, "reason": "disabled"}
+    )
+
+    evidence: dict[str, list[dict[str, Any]]] = {}
+    _append_identity_evidence(evidence, "sysinfo", sysinfo.get("identity"))
+    _append_identity_evidence(
+        evidence,
+        "sysinfo_extended",
+        sysinfo_extended.get("identity"),
+    )
+    _append_plain_evidence(evidence, "hardware", snapshot.get("hardware"))
+    _append_identity_evidence(
+        evidence,
+        "live_scsi",
+        live_scsi.get("identity"),
+    )
+    _append_identity_evidence(
+        evidence,
+        "usb_vendor",
+        live_usb_vendor.get("identity"),
+    )
+
+    usb_details = {
+        key: snapshot["hardware"].get(key)
+        for key in (
+            "usb_vid",
+            "usb_pid",
+            "firewire_guid",
+            "usbstor_instance_id",
+            "usb_parent_instance_id",
+            "usb_grandparent_instance_id",
+        )
+        if snapshot["hardware"].get(key) not in (None, "")
+    }
+
+    report = {
+        "mount_path": mount_path,
+        "mount_name": _mount_name(mount_path),
+        "sysinfo": sysinfo,
+        "disk_sysinfo_extended": sysinfo_extended,
+        "live_scsi_vpd": live_scsi,
+        "live_windows_scsi_vpd": live_windows_scsi,
+        "live_usb_vendor": live_usb_vendor,
+        "standard_inquiry": live_scsi.get("standard_inquiry", {}),
+        "usb_details": usb_details,
+        "final_resolved_identity": final_identity,
+        "resolver_conflicts": final_identity.get("_conflicts", []),
+        "all_identity_evidence": evidence,
+        "rejected_conflicting_evidence": _rejected_conflicts(
+            final_identity,
+            evidence,
+        ),
+    }
+    return _json_safe(report, include_raw=include_raw)
+
+
+def _default_paths() -> list[str]:
+    from .scanner import _find_ipod_volumes
+
+    return [mount for mount, _display in _find_ipod_volumes()]
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(
+        description="Dump read-only iPod identity evidence for debugging.",
+    )
+    parser.add_argument("paths", nargs="*", help="Mounted iPod path(s)")
+    parser.add_argument(
+        "--all",
+        action="store_true",
+        help="Dump every mounted volume containing iPod_Control",
+    )
+    parser.add_argument(
+        "--include-raw",
+        action="store_true",
+        help="Include raw SysInfoExtended text in the JSON output",
+    )
+    parser.add_argument(
+        "--no-usb-vendor",
+        action="store_true",
+        help="Skip the USB vendor-control diagnostic probe",
+    )
+    args = parser.parse_args(argv)
+
+    paths = list(args.paths)
+    if args.all or not paths:
+        paths.extend(path for path in _default_paths() if path not in paths)
+
+    if not paths:
+        print("No iPod volumes found.", file=sys.stderr)
+        return 1
+
+    reports = [
+        dump_device_info(
+            path,
+            include_raw=args.include_raw,
+            probe_usb_vendor=not args.no_usb_vendor,
+        )
+        for path in paths
+    ]
+    payload: Any = reports[0] if len(reports) == 1 else reports
+    print(json.dumps(payload, indent=2, ensure_ascii=False))
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

src/vendor/ipod_device/images.py

@@ -0,0 +1,408 @@
+"""iPod product image mapping and accent color extraction.
+
+Maps iPod model families, generations, and colors to official Apple device
+icons stored in assets/ipod_images/.  Also maps each icon to an (R,G,B)
+accent color for the "Match iPod" theme setting.
+"""
+
+from .models import IPOD_MODELS
+
+# Key: (model_family_lower, generation_lower, color_lower) → filename
+COLOR_MAP: dict[tuple[str, str, str], str] = {
+    # ── iPod (1G–4G) ────────────────────────────────────────
+    ("ipod", "1st gen", "white"): "iPod1.png",
+    ("ipod", "2nd gen", "white"): "iPod1.png",
+    ("ipod", "3rd gen", "white"): "iPod2.png",
+    ("ipod", "4th gen", "white"): "iPod4-White.png",
+    ("ipod u2", "4th gen", "black"): "iPod4-BlackRed.png",
+
+    # ── iPod Photo / iPod with Color Display (4th gen)──────
+    ("ipod photo", "4th gen", "white"): "iPod5-White.png",
+    ("ipod photo u2", "4th gen", "black"): "iPod5-BlackRed.png",
+
+    # ── iPod with Video (5th Gen / 5.5th Gen) ────────────
+    ("ipod video", "5th gen", "white"): "iPod6-White.png",
+    ("ipod video", "5th gen", "black"): "iPod6-Black.png",
+    ("ipod video", "5.5th gen", "white"): "iPod6-White.png",
+    ("ipod video", "5.5th gen", "black"): "iPod6-Black.png",
+    ("ipod video u2", "5th gen", "black"): "iPod6-BlackRed.png",
+    ("ipod video u2", "5.5th gen", "black"): "iPod6-BlackRed.png",
+
+    # ── iPod Classic (1st–3rd Gen) ───────────────────────
+    ("ipod classic", "1st gen", "silver"): "iPod11-Silver.png",
+    ("ipod classic", "1st gen", "black"): "iPod11-Black.png",
+    ("ipod classic", "2nd gen", "silver"): "iPod11-Silver.png",
+    ("ipod classic", "2nd gen", "black"): "iPod11B-Black.png",
+    ("ipod classic", "3rd gen", "silver"): "iPod11-Silver.png",
+    ("ipod classic", "3rd gen", "black"): "iPod11B-Black.png",
+
+    # ── iPod Mini 1st Gen ────────────
+    ("ipod mini", "1st gen", "silver"): "iPod3-Silver.png",
+    ("ipod mini", "1st gen", "blue"): "iPod3-Blue.png",
+    ("ipod mini", "1st gen", "gold"): "iPod3-Gold.png",
+    ("ipod mini", "1st gen", "green"): "iPod3-Green.png",
+    ("ipod mini", "1st gen", "pink"): "iPod3-Pink.png",
+
+    # ── iPod Mini 2nd Gen ───
+    ("ipod mini", "2nd gen", "silver"): "iPod3-Silver.png",
+    ("ipod mini", "2nd gen", "blue"): "iPod3B-Blue.png",
+    ("ipod mini", "2nd gen", "green"): "iPod3B-Green.png",
+    ("ipod mini", "2nd gen", "pink"): "iPod3B-Pink.png",
+
+    # ── iPod Nano 1st Gen ──────────────────────────────
+    ("ipod nano", "1st gen", "white"): "iPod7-White.png",
+    ("ipod nano", "1st gen", "black"): "iPod7-Black.png",
+
+    # ── iPod Nano 2nd Gen ─────
+    ("ipod nano", "2nd gen", "silver"): "iPod9-Silver.png",
+    ("ipod nano", "2nd gen", "black"): "iPod9-Black.png",
+    ("ipod nano", "2nd gen", "blue"): "iPod9-Blue.png",
+    ("ipod nano", "2nd gen", "green"): "iPod9-Green.png",
+    ("ipod nano", "2nd gen", "pink"): "iPod9-Pink.png",
+    ("ipod nano", "2nd gen", "red"): "iPod9-Red.png",
+
+    # ── iPod Nano 3rd Gen ─────
+    ("ipod nano", "3rd gen", "silver"): "iPod12-Silver.png",
+    ("ipod nano", "3rd gen", "black"): "iPod12-Black.png",
+    ("ipod nano", "3rd gen", "blue"): "iPod12-Blue.png",
+    ("ipod nano", "3rd gen", "green"): "iPod12-Green.png",
+    ("ipod nano", "3rd gen", "pink"): "iPod12-Pink.png",
+    ("ipod nano", "3rd gen", "red"): "iPod12-Red.png",
+
+    # ── iPod Nano 4th Gen ─────────────────────────────────
+    ("ipod nano", "4th gen", "silver"): "iPod15-Silver.png",
+    ("ipod nano", "4th gen", "black"): "iPod15-Black.png",
+    ("ipod nano", "4th gen", "blue"): "iPod15-Blue.png",
+    ("ipod nano", "4th gen", "green"): "iPod15-Green.png",
+    ("ipod nano", "4th gen", "orange"): "iPod15-Orange.png",
+    ("ipod nano", "4th gen", "pink"): "iPod15-Pink.png",
+    ("ipod nano", "4th gen", "purple"): "iPod15-Purple.png",
+    ("ipod nano", "4th gen", "red"): "iPod15-Red.png",
+    ("ipod nano", "4th gen", "yellow"): "iPod15-Yellow.png",
+
+    # ── iPod Nano 5th Gen ─────────────────────────────────
+    ("ipod nano", "5th gen", "silver"): "iPod16-Silver.png",
+    ("ipod nano", "5th gen", "black"): "iPod16-Black.png",
+    ("ipod nano", "5th gen", "blue"): "iPod16-Blue.png",
+    ("ipod nano", "5th gen", "green"): "iPod16-Green.png",
+    ("ipod nano", "5th gen", "orange"): "iPod16-Orange.png",
+    ("ipod nano", "5th gen", "pink"): "iPod16-Pink.png",
+    ("ipod nano", "5th gen", "purple"): "iPod16-Purple.png",
+    ("ipod nano", "5th gen", "red"): "iPod16-Red.png",
+    ("ipod nano", "5th gen", "yellow"): "iPod16-Yellow.png",
+
+    # ── iPod Nano 6th Gen ─────────────────────────────────
+    ("ipod nano", "6th gen", "silver"): "iPod17-Silver.png",
+    ("ipod nano", "6th gen", "graphite"): "iPod17-DarkGray.png",
+    ("ipod nano", "6th gen", "blue"): "iPod17-Blue.png",
+    ("ipod nano", "6th gen", "green"): "iPod17-Green.png",
+    ("ipod nano", "6th gen", "orange"): "iPod17-Orange.png",
+    ("ipod nano", "6th gen", "pink"): "iPod17-Pink.png",
+    ("ipod nano", "6th gen", "red"): "iPod17-Red.png",
+
+    # ── iPod Nano 7th Gen ─────────────────────────────────────────────
+    ("ipod nano", "7th gen", "silver"): "iPod18A-Silver.png",
+    ("ipod nano", "7th gen", "space gray"): "iPod18A-SpaceGray.png",
+    ("ipod nano", "7th gen", "blue"): "iPod18A-Blue.png",
+    ("ipod nano", "7th gen", "pink"): "iPod18A-Pink.png",
+    ("ipod nano", "7th gen", "red"): "iPod18A-Red.png",
+    ("ipod nano", "7th gen", "gold"): "iPod18A-Gold.png",
+    ("ipod nano", "7th gen", "slate"): "iPod18-DarkGray.png",
+    ("ipod nano", "7th gen", "green"): "iPod18-Green.png",
+    ("ipod nano", "7th gen", "purple"): "iPod18-Purple.png",
+    ("ipod nano", "7th gen", "yellow"): "iPod18-Yellow.png",
+
+    # ── iPod Shuffle 1st Gen ───────────────────────
+    ("ipod shuffle", "1st gen", "white"): "iPod128.png",
+
+    # ── iPod Shuffle 2nd Gen ──────────────────────────────────────────
+    ("ipod shuffle", "2nd gen", "silver"): "iPod130-Silver.png",
+    ("ipod shuffle", "2nd gen", "blue"): "iPod130-Blue.png",
+    ("ipod shuffle", "2nd gen", "green"): "iPod130-Green.png",
+    ("ipod shuffle", "2nd gen", "pink"): "iPod130-Pink.png",
+    ("ipod shuffle", "2nd gen", "orange"): "iPod130-Orange.png",
+    ("ipod shuffle", "2nd gen", "purple"): "iPod130C-Purple.png",
+    ("ipod shuffle", "2nd gen", "red"): "iPod130C-Red.png",
+    ("ipod shuffle", "2nd gen", "gold"): "iPod130F-Gold.png",
+
+    # ── iPod Shuffle 3rd Gen ───────────────────────────────────
+    ("ipod shuffle", "3rd gen", "silver"): "iPod132-Silver.png",
+    ("ipod shuffle", "3rd gen", "black"): "iPod132-DarkGray.png",
+    ("ipod shuffle", "3rd gen", "blue"): "iPod132-Blue.png",
+    ("ipod shuffle", "3rd gen", "green"): "iPod132-Green.png",
+    ("ipod shuffle", "3rd gen", "pink"): "iPod132-Pink.png",
+    ("ipod shuffle", "3rd gen", "stainless steel"): "iPod132B-Silver.png",
+
+    # ── iPod Shuffle 4th Gen (2010–2017) ───────────────────────────────
+    ("ipod shuffle", "4th gen", "silver"): "iPod133D-Silver.png",
+    ("ipod shuffle", "4th gen", "space gray"): "iPod133D-SpaceGray.png",
+    ("ipod shuffle", "4th gen", "blue"): "iPod133D-Blue.png",
+    ("ipod shuffle", "4th gen", "pink"): "iPod133D-Pink.png",
+    ("ipod shuffle", "4th gen", "red"): "iPod133D-Red.png",
+    ("ipod shuffle", "4th gen", "gold"): "iPod133D-Gold.png",
+    ("ipod shuffle", "4th gen", "slate"): "iPod133B-DarkGray.png",
+    ("ipod shuffle", "4th gen", "green"): "iPod133B-Green.png",
+    ("ipod shuffle", "4th gen", "purple"): "iPod133B-Purple.png",
+    ("ipod shuffle", "4th gen", "yellow"): "iPod133B-Yellow.png",
+    ("ipod shuffle", "4th gen", "orange"): "iPod133-Orange.png",
+}
+
+MODEL_IMAGE: dict[str, str] = {
+    # ── iPod Nano 7th Gen (2012 original → iPod18) ─────────────────────
+    'MD475': 'iPod18-Pink.png',
+    'MD476': 'iPod18-Yellow.png',
+    'MD477': 'iPod18-Blue.png',
+    'MD478': 'iPod18-Green.png',
+    'MD479': 'iPod18-Purple.png',
+    'MD480': 'iPod18-Silver.png',
+    'MD481': 'iPod18-DarkGray.png',
+    'MD744': 'iPod18-Red.png',
+    'ME971': 'iPod18-SpaceGray.png',
+    # ── iPod Nano 7th Gen (2015 refresh → iPod18A) ─────────────────────
+    'MKMV2': 'iPod18A-Pink.png',
+    'MKMX2': 'iPod18A-Gold.png',
+    'MKN02': 'iPod18A-Blue.png',
+    'MKN22': 'iPod18A-Silver.png',
+    'MKN52': 'iPod18A-SpaceGray.png',
+    'MKN72': 'iPod18A-Red.png',
+    # ── iPod Shuffle 2nd Gen — Sept 2007 Rev A (iPod130C) ─────────────
+    'MB227': 'iPod130C-Blue.png',
+    'MB228': 'iPod130C-Blue.png',
+    'MB229': 'iPod130C-Green.png',
+    'MB520': 'iPod130C-Blue.png',
+    'MB522': 'iPod130C-Green.png',
+    # ── iPod Shuffle 2nd Gen — 2008 Rev B (iPod130F) ──────────────────
+    'MB811': 'iPod130F-Pink.png',
+    'MB813': 'iPod130F-Blue.png',
+    'MB815': 'iPod130F-Green.png',
+    'MB817': 'iPod130F-Red.png',
+    'MB681': 'iPod130F-Pink.png',
+    'MB683': 'iPod130F-Blue.png',
+    'MB685': 'iPod130F-Green.png',
+    'MB779': 'iPod130F-Red.png',
+    # ── iPod Shuffle 4th Gen — 2010 original (iPod133) ────────────────
+    'MC584': 'iPod133-Silver.png',
+    'MC585': 'iPod133-Pink.png',
+    'MC750': 'iPod133-Green.png',
+    'MC751': 'iPod133-Blue.png',
+    # ── iPod Shuffle 4th Gen — Late 2012 Rev A (iPod133B) ─────────────
+    'MD773': 'iPod133B-Pink.png',
+    'MD775': 'iPod133B-Blue.png',
+    'MD778': 'iPod133B-Silver.png',
+    'MD780': 'iPod133B-Red.png',
+    'ME949': 'iPod133B-SpaceGray.png',
+}
+
+FAMILY_FALLBACK: dict[str, str] = {
+    "ipod": "iPod4-White.png",
+    "ipod u2": "iPod4-BlackRed.png",
+    "ipod photo": "iPod5-White.png",
+    "ipod photo u2": "iPod5-BlackRed.png",
+    "ipod video": "iPod6-White.png",
+    "ipod video u2": "iPod6-BlackRed.png",
+    "ipod classic": "iPod11-Silver.png",
+    "ipod mini": "iPod3-Silver.png",
+    "ipod nano": "iPod15-Silver.png",
+    "ipod shuffle": "iPod133D-Silver.png",
+}
+
+GENERIC_IMAGE = "iPodGeneric.png"
+
+
+# ── Image → accent color (R, G, B) ───────────────────────────────────────────
+# Maps image filename (case-insensitive, without extension) to the dominant
+# body color of that iPod model.  Used by the "Match iPod" accent color
+# setting.  White/silver models use a generic silver; black/gray use a
+# generic dark gray; colorful models use their actual body tint.
+_SILVER = (223, 224, 223)
+_GRAY = (44, 44, 49)
+
+IMAGE_COLORS: dict[str, tuple[int, int, int]] = {
+    # ── iPod (original / Photo / Video / Classic) ─────────────────────
+    "ipod1": _SILVER,
+    "ipod2": _SILVER,
+    "ipod4-white": _SILVER,
+    "ipod4-blackred": (163, 36, 24),
+    "ipod5-white": _SILVER,
+    "ipod5-blackred": (163, 36, 24),
+    "ipod6-white": _SILVER,
+    "ipod6-black": _GRAY,
+    "ipod6-blackred": (233, 51, 35),
+    "ipod11-silver": _SILVER,
+    "ipod11-black": _GRAY,
+    "ipod11b-black": _GRAY,
+    # ── iPod Mini 1st Gen ─────────────────────────────────────────────
+    "ipod3-silver": _SILVER,
+    "ipod3-blue": (137, 178, 204),
+    "ipod3-gold": (217, 201, 140),
+    "ipod3-green": (196, 208, 139),
+    "ipod3-pink": (216, 173, 201),
+    # ── iPod Mini 2nd Gen ─────────────────────────────────────────────
+    "ipod3b-blue": (121, 184, 229),
+    "ipod3b-green": (211, 230, 120),
+    "ipod3b-pink": (225, 156, 203),
+    # ── iPod Nano 1st Gen ─────────────────────────────────────────────
+    "ipod7-white": _SILVER,
+    "ipod7-black": _GRAY,
+    # ── iPod Nano 2nd Gen ─────────────────────────────────────────────
+    "ipod9-silver": _SILVER,
+    "ipod9-black": _GRAY,
+    "ipod9-blue": (94, 194, 210),
+    "ipod9-green": (172, 199, 84),
+    "ipod9-pink": (209, 61, 139),
+    "ipod9-red": (206, 67, 66),
+    # ── iPod Nano 3rd Gen ─────────────────────────────────────────────
+    "ipod12-silver": _SILVER,
+    "ipod12-black": _GRAY,
+    "ipod12-blue": (206, 67, 66),
+    "ipod12-green": (170, 220, 168),
+    "ipod12-pink": (200, 80, 146),
+    "ipod12-red": (154, 63, 81),
+    # ── iPod Nano 4th Gen ─────────────────────────────────────────────
+    "ipod15-silver": _SILVER,
+    "ipod15-black": _GRAY,
+    "ipod15-blue": (62, 127, 180),
+    "ipod15-green": (131, 173, 68),
+    "ipod15-orange": (208, 131, 57),
+    "ipod15-pink": (227, 67, 133),
+    "ipod15-purple": (126, 45, 199),
+    "ipod15-red": (209, 62, 66),
+    "ipod15-yellow": (239, 230, 109),
+    # ── iPod Nano 5th Gen ─────────────────────────────────────────────
+    "ipod16-silver": _SILVER,
+    "ipod16-black": _GRAY,
+    "ipod16-blue": (26, 67, 145),
+    "ipod16-green": (52, 119, 61),
+    "ipod16-orange": (215, 102, 43),
+    "ipod16-pink": (217, 49, 103),
+    "ipod16-purple": (65, 9, 127),
+    "ipod16-red": (146, 28, 45),
+    "ipod16-yellow": (236, 209, 78),
+    # ── iPod Nano 6th Gen ─────────────────────────────────────────────
+    "ipod17-silver": _SILVER,
+    "ipod17-darkgray": _GRAY,
+    "ipod17-blue": (105, 128, 168),
+    "ipod17-green": (135, 151, 69),
+    "ipod17-orange": (178, 131, 57),
+    "ipod17-pink": (182, 91, 125),
+    "ipod17-red": (186, 50, 48),
+    # ── iPod Nano 7th Gen (2012 iPod18) ───────────────────────────────
+    "ipod18-silver": _SILVER,
+    "ipod18-darkgray": _GRAY,
+    "ipod18-blue": (91, 187, 212),
+    "ipod18-green": (146, 224, 163),
+    "ipod18-pink": (222, 132, 128),
+    "ipod18-purple": (222, 152, 208),
+    "ipod18-red": (216, 68, 61),
+    "ipod18-yellow": (217, 218, 91),
+    "ipod18-spacegray": _GRAY,
+    # ── iPod Nano 7th Gen (2015 iPod18A) ──────────────────────────────
+    "ipod18a-silver": _SILVER,
+    "ipod18a-spacegray": _GRAY,
+    "ipod18a-blue": (109, 165, 229),
+    "ipod18a-gold": (216, 204, 185),
+    "ipod18a-pink": (236, 115, 167),
+    "ipod18a-red": (232, 105, 97),
+    # ── iPod Shuffle 1st Gen ──────────────────────────────────────────
+    "ipod128": _SILVER,
+    # ── iPod Shuffle 2nd Gen (iPod130) ────────────────────────────────
+    "ipod130-silver": _SILVER,
+    "ipod130-blue": (81, 169, 195),
+    "ipod130-green": (165, 198, 75),
+    "ipod130-orange": (230, 107, 44),
+    "ipod130-pink": (198, 52, 129),
+    # ── iPod Shuffle 2nd Gen Rev A (iPod130C) ─────────────────────────
+    "ipod130c-blue": (152, 205, 206),
+    "ipod130c-green": (167, 217, 164),
+    "ipod130c-purple": (131, 131, 201),
+    "ipod130c-red": (150, 59, 77),
+    # ── iPod Shuffle 2nd Gen Rev B (iPod130F) ─────────────────────────
+    "ipod130f-blue": (50, 110, 179),
+    "ipod130f-gold": (208, 189, 129),
+    "ipod130f-green": (128, 178, 63),
+    "ipod130f-pink": (205, 58, 115),
+    "ipod130f-red": (179, 42, 40),
+    # ── iPod Shuffle 3rd Gen (iPod132) ────────────────────────────────
+    "ipod132-silver": _SILVER,
+    "ipod132-darkgray": _GRAY,
+    "ipod132-blue": (73, 156, 177),
+    "ipod132-green": (147, 189, 77),
+    "ipod132-pink": (204, 75, 117),
+    "ipod132b-silver": _SILVER,
+    # ── iPod Shuffle 4th Gen (2010 iPod133) ───────────────────────────
+    "ipod133-silver": _SILVER,
+    "ipod133-blue": (139, 175, 212),
+    "ipod133-green": (181, 221, 105),
+    "ipod133-orange": (224, 186, 109),
+    "ipod133-pink": (220, 134, 179),
+    # ── iPod Shuffle 4th Gen (2012 iPod133B) ──────────────────────────
+    "ipod133b-silver": _SILVER,
+    "ipod133b-darkgray": _GRAY,
+    "ipod133b-blue": (89, 194, 217),
+    "ipod133b-green": (146, 219, 162),
+    "ipod133b-pink": (219, 122, 118),
+    "ipod133b-purple": (212, 143, 199),
+    "ipod133b-red": (216, 69, 62),
+    "ipod133b-yellow": (213, 213, 89),
+    # ── iPod Shuffle 4th Gen (2015 iPod133D) ──────────────────────────
+    "ipod133d-silver": _SILVER,
+    "ipod133d-spacegray": _GRAY,
+    "ipod133d-blue": (67, 129, 202),
+    "ipod133d-gold": (244, 233, 215),
+    "ipod133d-pink": (237, 115, 167),
+    "ipod133d-red": (223, 85, 76),
+}
+
+
+def color_for_image(image_filename: str) -> tuple[int, int, int] | None:
+    """Return the (R, G, B) accent color for an iPod image filename.
+
+    Returns None if the image is not in the mapping (e.g. iPodGeneric).
+    """
+    key = image_filename.rsplit(".", 1)[0].lower()
+    return IMAGE_COLORS.get(key)
+
+
+_DEFAULT_COLOR_PREFERENCE = ("silver", "white")
+
+
+def resolve_image_filename(
+    family: str,
+    generation: str,
+    color: str = "",
+) -> str:
+    """Resolve an image filename through a tiered lookup.
+
+    1. Exact (family, generation, color)
+    2. Inferred default — try "silver" then "white" for (family, generation)
+    3. Family-level fallback
+    4. ``iPodGeneric.png``
+    """
+    fam = family.lower()
+    gen = generation.lower()
+    col = color.lower().strip()
+
+    if col:
+        filename = COLOR_MAP.get((fam, gen, col))
+        if filename:
+            return filename
+
+    for default_col in _DEFAULT_COLOR_PREFERENCE:
+        filename = COLOR_MAP.get((fam, gen, default_col))
+        if filename:
+            return filename
+
+    return FAMILY_FALLBACK.get(fam, GENERIC_IMAGE)
+
+
+def image_for_model(model_number: str) -> str:
+    """Return the exact image filename for a known model number."""
+    override = MODEL_IMAGE.get(model_number)
+    if override:
+        return override
+
+    info = IPOD_MODELS.get(model_number)
+    if info:
+        return resolve_image_filename(info[0], info[1], info[3])
+
+    return GENERIC_IMAGE

src/vendor/ipod_device/lookup.py

@@ -0,0 +1,170 @@
+"""Model lookup functions — identify iPods from model numbers, serials, etc."""
+
+import re
+
+from .capabilities import _FAMILY_GEN_CAPABILITIES
+from .models import IPOD_MODELS, SERIAL_LAST3_TO_MODEL
+
+
+def _identity_text(value: str | None) -> str:
+    return " ".join(str(value or "").strip().casefold().split())
+
+
+def extract_model_number(model_str: str) -> str | None:
+    """Extract normalised model number from ModelNumStr.
+
+    ModelNumStr format varies:
+    - ``"xA623"`` → ``"MA623"``
+    - ``"MC293"`` → ``"MC293"``
+    - ``"M9282"`` → ``"M9282"``
+    - ``"P9804"`` → ``"M9804"``  (SysInfo sometimes uses non-M first char)
+    """
+    if not model_str:
+        return None
+
+    # Normalise 'x' prefix: "xA623" → "MA623"
+    if model_str.startswith('x'):
+        model_str = 'M' + model_str[1:]
+
+    match = re.match(r'^(M[A-Z]?\d{3,4})', model_str.upper())
+    if match:
+        return match.group(1)
+
+    # Some SysInfo ModelNumStr values use a non-M first character (e.g. "P9804"
+    # instead of "M9804").  Try substituting M and re-matching.
+    alt = 'M' + model_str[1:]
+    match = re.match(r'^(M[A-Z]?\d{3,4})', alt.upper())
+    if match:
+        return match.group(1)
+
+    return model_str.upper()[:5] if len(model_str) >= 5 else model_str.upper()
+
+
+def usb_pid_identity_conflicts(
+    model_family: str,
+    generation: str,
+    pid_family: str,
+    pid_generation: str,
+) -> bool:
+    """Return True when an exact model tuple cannot belong to a USB PID hint."""
+    model_family_norm = _identity_text(model_family)
+    pid_family_norm = _identity_text(pid_family)
+    if not model_family_norm or not pid_family_norm:
+        return False
+
+    model_generation_norm = _identity_text(generation)
+    pid_generation_norm = _identity_text(pid_generation)
+    if pid_family_norm == "ipod" and not pid_generation_norm:
+        return False
+
+    family_compatible = model_family_norm == pid_family_norm
+
+    # Special editions use more specific family labels than USB PID tables.
+    if not family_compatible and "u2" in model_family_norm:
+        family_compatible = model_family_norm.startswith(pid_family_norm + " ")
+
+    if not family_compatible:
+        return True
+
+    if not model_generation_norm or not pid_generation_norm:
+        return False
+    if model_generation_norm == pid_generation_norm:
+        return False
+
+    # The Video 5.5G uses the same coarse USB PID family as the Video 5G.
+    if (
+        pid_family_norm == "ipod video"
+        and pid_generation_norm == "5th gen"
+        and model_generation_norm == "5.5th gen"
+    ):
+        return False
+
+    return True
+
+
+def get_model_info(model_number: str | None) -> tuple[str, str, str, str] | None:
+    """Get detailed model information from model number.
+
+    Returns:
+        Tuple of ``(name, generation, capacity, color)`` or ``None``.
+    """
+    if not model_number:
+        return None
+
+    if model_number in IPOD_MODELS:
+        return IPOD_MODELS[model_number]
+
+    # If the first character isn't M, try substituting M (handles SysInfo quirks)
+    if not model_number.startswith('M') and len(model_number) > 1:
+        alt = 'M' + model_number[1:]
+        if alt in IPOD_MODELS:
+            return IPOD_MODELS[alt]
+
+    for prefix, info in IPOD_MODELS.items():
+        if model_number.startswith(prefix[:4]):
+            return info
+
+    return None
+
+
+def get_friendly_model_name(model_number: str | None) -> str:
+    """Return a user-friendly model name string."""
+    info = get_model_info(model_number)
+    if info:
+        name, gen, capacity, color = info
+        parts = [name, capacity]
+        if color:
+            parts.append(color)
+        if gen:
+            parts.append(f"({gen})")
+        return " ".join(p for p in parts if p)
+    return f"Unknown iPod ({model_number})" if model_number else "Unknown iPod"
+
+
+def lookup_by_serial(serial: str) -> tuple[str, tuple[str, str, str, str]] | None:
+    """Look up iPod model from a serial number's last 3 characters.
+
+    Returns:
+        ``(model_number, (family, generation, capacity, color))`` or ``None``.
+    """
+    if not serial or len(serial) < 3:
+        return None
+    model_num = SERIAL_LAST3_TO_MODEL.get(serial[-3:])
+    if not model_num:
+        return None
+    info = IPOD_MODELS.get(model_num)
+    if not info:
+        return None
+    return (model_num, info)
+
+
+def infer_generation(
+    family: str,
+    capacity: str = "",
+) -> str | None:
+    """Best-effort generation inference from family + available signals.
+
+    Uses the model table to find which generations match a given capacity.
+    If only one generation of a family offers that capacity, we can infer
+    the generation with certainty (e.g. iPod Classic 120GB → 2nd Gen).
+
+    Falls back to returning the sole generation if a family has only one.
+    Returns ``None`` when the generation is ambiguous.
+    """
+    if not family:
+        return None
+
+    family_gens = {g for (f, g) in _FAMILY_GEN_CAPABILITIES if f == family}
+
+    if len(family_gens) == 1:
+        return family_gens.pop()
+
+    if capacity:
+        matching_gens: set[str] = set()
+        for _mn, (_mf, _mg, _mc, _color) in IPOD_MODELS.items():
+            if _mf == family and _mc == capacity:
+                matching_gens.add(_mg)
+        if len(matching_gens) == 1:
+            return matching_gens.pop()
+
+    return None

src/vendor/ipod_device/models.py

@@ -0,0 +1,509 @@
+"""iPod model identification databases — model numbers, USB PIDs, and serial suffixes.
+
+Data tables
+~~~~~~~~~~~
+- ``IPOD_MODELS``            Model number → (family, gen, capacity, color)
+- ``USB_PID_TO_MODEL``       USB Product ID → (family, gen)
+- ``IPOD_USB_PIDS``          All known iPod USB Product IDs (frozenset)
+- ``SERIAL_LAST3_TO_MODEL``  Serial suffix → model number
+
+Sources
+~~~~~~~
+- Universal Compendium iPod Models table (universalcompendium.com)
+- The Apple Wiki: Models/iPod (theapplewiki.com)
+- Linux USB ID Repository
+- libgpod ``itdb_device.c``
+"""
+
+
+# ╔═══════════════════════════════════════════════════════════════════════════╗
+# ║  Comprehensive iPod model database                                      ║
+# ╚═══════════════════════════════════════════════════════════════════════════╝
+#
+# Maps order number prefixes to (product_line, generation, capacity, color)
+#
+# Generation naming conventions:
+#   The full-size iPod line has TWO numbering systems. This table uses the
+#   product-specific generation (matching what users see in "About" screens),
+#   with the overall iPod lineage noted in comments.
+#
+#   Overall iPod gen │ Product-specific gen │ Years │ Apple Model
+#   ─────────────────┼──────────────────────┼───────┼────────────
+#   1st gen           │ iPod 1st Gen         │ 2001  │ M8541
+#   2nd gen           │ iPod 2nd Gen         │ 2002  │ A1019
+#   3rd gen           │ iPod 3rd Gen         │ 2003  │ A1040
+#   4th gen           │ iPod 4th Gen         │ 2004  │ A1059
+#   4th gen (color)   │ iPod Photo           │ 2004  │ A1099
+#   5th gen           │ iPod Video 5th Gen   │ 2005  │ A1136
+#   5.5th gen         │ iPod Video 5.5th Gen │ 2006  │ A1136 (Rev B)
+#   6th gen           │ iPod Classic 1st Gen │ 2007  │ A1238
+#   6.5th gen         │ iPod Classic 2nd Gen │ 2008  │ A1238 (Rev A)
+#   7th gen           │ iPod Classic 3rd Gen │ 2009  │ A1238 (Rev B/C)
+
+IPOD_MODELS: dict[str, tuple[str, str, str, str]] = {
+    # ==========================================================================
+    # iPod Classic (2007-2009)
+    # ==========================================================================
+    'MB029': ("iPod Classic", "1st Gen", "80GB", "Silver"),
+    'MB147': ("iPod Classic", "1st Gen", "80GB", "Black"),
+    'MB145': ("iPod Classic", "1st Gen", "160GB", "Silver"),
+    'MB150': ("iPod Classic", "1st Gen", "160GB", "Black"),
+    'MB562': ("iPod Classic", "2nd Gen", "120GB", "Silver"),
+    'MB565': ("iPod Classic", "2nd Gen", "120GB", "Black"),
+    'MC293': ("iPod Classic", "3rd Gen", "160GB", "Silver"),
+    'MC297': ("iPod Classic", "3rd Gen", "160GB", "Black"),
+
+    # ==========================================================================
+    # iPod (Scroll Wheel) — 1st Generation (2001)
+    # ==========================================================================
+    'M8513': ("iPod", "1st Gen", "5GB", "White"),
+    'M8541': ("iPod", "1st Gen", "5GB", "White"),
+    'M8697': ("iPod", "1st Gen", "5GB", "White"),
+    'M8709': ("iPod", "1st Gen", "10GB", "White"),
+
+    # ==========================================================================
+    # iPod (Touch Wheel) — 2nd Generation (2002)
+    # ==========================================================================
+    'M8737': ("iPod", "2nd Gen", "10GB", "White"),
+    'M8740': ("iPod", "2nd Gen", "10GB", "White"),
+    'M8738': ("iPod", "2nd Gen", "20GB", "White"),
+    'M8741': ("iPod", "2nd Gen", "20GB", "White"),
+
+    # ==========================================================================
+    # iPod (Dock Connector) — 3rd Generation (2003)
+    # ==========================================================================
+    'M8976': ("iPod", "3rd Gen", "10GB", "White"),
+    'M8946': ("iPod", "3rd Gen", "15GB", "White"),
+    'M8948': ("iPod", "3rd Gen", "30GB", "White"),
+    'M9244': ("iPod", "3rd Gen", "20GB", "White"),
+    'M9245': ("iPod", "3rd Gen", "40GB", "White"),
+    'M9460': ("iPod", "3rd Gen", "15GB", "White"),
+
+    # ==========================================================================
+    # iPod (Click Wheel) — 4th Generation (2004)
+    # ==========================================================================
+    'M9268': ("iPod", "4th Gen", "40GB", "White"),
+    'M9282': ("iPod", "4th Gen", "20GB", "White"),
+    'ME436': ("iPod", "4th Gen", "40GB", "White"),
+    'M9787': ("iPod U2", "4th Gen", "20GB", "Black"),
+
+    # ==========================================================================
+    # iPod Photo / iPod with color Display — 4th Gen (Color) (2004-2005)
+    # ==========================================================================
+    'M9585': ("iPod Photo", "4th Gen", "40GB", "White"),
+    'M9586': ("iPod Photo", "4th Gen", "60GB", "White"),
+    'M9829': ("iPod Photo", "4th Gen", "30GB", "White"),
+    'M9830': ("iPod Photo", "4th Gen", "60GB", "White"),
+    'MA079': ("iPod Photo", "4th Gen", "20GB", "White"),
+    'MA127': ("iPod U2", "4th Gen", "20GB", "Black"),
+    'MS492': ("iPod Photo", "4th Gen", "30GB", "White"),
+    'MA215': ("iPod Photo", "4th Gen", "20GB", "White"),
+
+    # ==========================================================================
+    # iPod Video — 5th Generation (2005)
+    # ==========================================================================
+    'MA002': ("iPod Video", "5th Gen", "30GB", "White"),
+    'MA003': ("iPod Video", "5th Gen", "60GB", "White"),
+    'MA146': ("iPod Video", "5th Gen", "30GB", "Black"),
+    'MA147': ("iPod Video", "5th Gen", "60GB", "Black"),
+    'MA452': ("iPod Video U2", "5th Gen", "30GB", "Black"),
+
+    # ==========================================================================
+    # iPod Video — 5.5th Generation / Enhanced (Late 2006)
+    # ==========================================================================
+    'MA444': ("iPod Video", "5.5th Gen", "30GB", "White"),
+    'MA446': ("iPod Video", "5.5th Gen", "30GB", "Black"),
+    'MA448': ("iPod Video", "5.5th Gen", "80GB", "White"),
+    'MA450': ("iPod Video", "5.5th Gen", "80GB", "Black"),
+    'MA664': ("iPod Video U2", "5.5th Gen", "30GB", "Black"),
+
+    # ==========================================================================
+    # iPod Mini — 1st Generation (2004)
+    # ==========================================================================
+    'M9160': ("iPod Mini", "1st Gen", "4GB", "Silver"),
+    'M9434': ("iPod Mini", "1st Gen", "4GB", "Green"),
+    'M9435': ("iPod Mini", "1st Gen", "4GB", "Pink"),
+    'M9436': ("iPod Mini", "1st Gen", "4GB", "Blue"),
+    'M9437': ("iPod Mini", "1st Gen", "4GB", "Gold"),
+
+    # ==========================================================================
+    # iPod Mini — 2nd Generation (2005)
+    # ==========================================================================
+    'M9800': ("iPod Mini", "2nd Gen", "4GB", "Silver"),
+    'M9801': ("iPod Mini", "2nd Gen", "6GB", "Silver"),
+    'M9802': ("iPod Mini", "2nd Gen", "4GB", "Blue"),
+    'M9803': ("iPod Mini", "2nd Gen", "6GB", "Blue"),
+    'M9804': ("iPod Mini", "2nd Gen", "4GB", "Pink"),
+    'M9805': ("iPod Mini", "2nd Gen", "6GB", "Pink"),
+    'M9806': ("iPod Mini", "2nd Gen", "4GB", "Green"),
+    'M9807': ("iPod Mini", "2nd Gen", "6GB", "Green"),
+
+    # ==========================================================================
+    # iPod Nano — 1st Generation (2005)
+    # ==========================================================================
+    'MA004': ("iPod Nano", "1st Gen", "2GB", "White"),
+    'MA005': ("iPod Nano", "1st Gen", "4GB", "White"),
+    'MA099': ("iPod Nano", "1st Gen", "2GB", "Black"),
+    'MA107': ("iPod Nano", "1st Gen", "4GB", "Black"),
+    'MA350': ("iPod Nano", "1st Gen", "1GB", "White"),
+    'MA352': ("iPod Nano", "1st Gen", "1GB", "Black"),
+
+    # ==========================================================================
+    # iPod Nano — 2nd Generation (2006)
+    # ==========================================================================
+    'MA426': ("iPod Nano", "2nd Gen", "4GB", "Silver"),
+    'MA428': ("iPod Nano", "2nd Gen", "4GB", "Blue"),
+    'MA477': ("iPod Nano", "2nd Gen", "2GB", "Silver"),
+    'MA487': ("iPod Nano", "2nd Gen", "4GB", "Green"),
+    'MA489': ("iPod Nano", "2nd Gen", "4GB", "Pink"),
+    'MA497': ("iPod Nano", "2nd Gen", "8GB", "Black"),
+    'MA725': ("iPod Nano", "2nd Gen", "4GB", "Red"),
+    'MA726': ("iPod Nano", "2nd Gen", "8GB", "Red"),
+    'MA899': ("iPod Nano", "2nd Gen", "8GB", "Red"),
+
+    # ==========================================================================
+    # iPod Nano — 3rd Generation (2007)
+    # ==========================================================================
+    'MA978': ("iPod Nano", "3rd Gen", "4GB", "Silver"),
+    'MA980': ("iPod Nano", "3rd Gen", "8GB", "Silver"),
+    'MB249': ("iPod Nano", "3rd Gen", "8GB", "Blue"),
+    'MB253': ("iPod Nano", "3rd Gen", "8GB", "Green"),
+    'MB257': ("iPod Nano", "3rd Gen", "8GB", "Red"),
+    'MB261': ("iPod Nano", "3rd Gen", "8GB", "Black"),
+    'MB453': ("iPod Nano", "3rd Gen", "8GB", "Pink"),
+
+    # ==========================================================================
+    # iPod Nano — 4th Generation (2008)
+    # ==========================================================================
+    'MB480': ("iPod Nano", "4th Gen", "4GB", "Silver"),
+    'MB651': ("iPod Nano", "4th Gen", "4GB", "Blue"),
+    'MB654': ("iPod Nano", "4th Gen", "4GB", "Pink"),
+    'MB657': ("iPod Nano", "4th Gen", "4GB", "Purple"),
+    'MB660': ("iPod Nano", "4th Gen", "4GB", "Orange"),
+    'MB663': ("iPod Nano", "4th Gen", "4GB", "Green"),
+    'MB666': ("iPod Nano", "4th Gen", "4GB", "Yellow"),
+    'MB598': ("iPod Nano", "4th Gen", "8GB", "Silver"),
+    'MB732': ("iPod Nano", "4th Gen", "8GB", "Blue"),
+    'MB735': ("iPod Nano", "4th Gen", "8GB", "Pink"),
+    'MB739': ("iPod Nano", "4th Gen", "8GB", "Purple"),
+    'MB742': ("iPod Nano", "4th Gen", "8GB", "Orange"),
+    'MB745': ("iPod Nano", "4th Gen", "8GB", "Green"),
+    'MB748': ("iPod Nano", "4th Gen", "8GB", "Yellow"),
+    'MB751': ("iPod Nano", "4th Gen", "8GB", "Red"),
+    'MB754': ("iPod Nano", "4th Gen", "8GB", "Black"),
+    'MB903': ("iPod Nano", "4th Gen", "16GB", "Silver"),
+    'MB905': ("iPod Nano", "4th Gen", "16GB", "Blue"),
+    'MB907': ("iPod Nano", "4th Gen", "16GB", "Pink"),
+    'MB909': ("iPod Nano", "4th Gen", "16GB", "Purple"),
+    'MB911': ("iPod Nano", "4th Gen", "16GB", "Orange"),
+    'MB913': ("iPod Nano", "4th Gen", "16GB", "Green"),
+    'MB915': ("iPod Nano", "4th Gen", "16GB", "Yellow"),
+    'MB917': ("iPod Nano", "4th Gen", "16GB", "Red"),
+    'MB918': ("iPod Nano", "4th Gen", "16GB", "Black"),
+
+    # ==========================================================================
+    # iPod Nano — 5th Generation (2009)
+    # ==========================================================================
+    'MC027': ("iPod Nano", "5th Gen", "8GB", "Silver"),
+    'MC031': ("iPod Nano", "5th Gen", "8GB", "Black"),
+    'MC034': ("iPod Nano", "5th Gen", "8GB", "Purple"),
+    'MC037': ("iPod Nano", "5th Gen", "8GB", "Blue"),
+    'MC040': ("iPod Nano", "5th Gen", "8GB", "Green"),
+    'MC043': ("iPod Nano", "5th Gen", "8GB", "Yellow"),
+    'MC046': ("iPod Nano", "5th Gen", "8GB", "Orange"),
+    'MC049': ("iPod Nano", "5th Gen", "8GB", "Red"),
+    'MC050': ("iPod Nano", "5th Gen", "8GB", "Pink"),
+    'MC060': ("iPod Nano", "5th Gen", "16GB", "Silver"),
+    'MC062': ("iPod Nano", "5th Gen", "16GB", "Black"),
+    'MC064': ("iPod Nano", "5th Gen", "16GB", "Purple"),
+    'MC066': ("iPod Nano", "5th Gen", "16GB", "Blue"),
+    'MC068': ("iPod Nano", "5th Gen", "16GB", "Green"),
+    'MC070': ("iPod Nano", "5th Gen", "16GB", "Yellow"),
+    'MC072': ("iPod Nano", "5th Gen", "16GB", "Orange"),
+    'MC074': ("iPod Nano", "5th Gen", "16GB", "Red"),
+    'MC075': ("iPod Nano", "5th Gen", "16GB", "Pink"),
+
+    # ==========================================================================
+    # iPod Nano — 6th Generation (2010)
+    # ==========================================================================
+    'MC525': ("iPod Nano", "6th Gen", "8GB", "Silver"),
+    'MC688': ("iPod Nano", "6th Gen", "8GB", "Graphite"),
+    'MC689': ("iPod Nano", "6th Gen", "8GB", "Blue"),
+    'MC690': ("iPod Nano", "6th Gen", "8GB", "Green"),
+    'MC691': ("iPod Nano", "6th Gen", "8GB", "Orange"),
+    'MC692': ("iPod Nano", "6th Gen", "8GB", "Pink"),
+    'MC693': ("iPod Nano", "6th Gen", "8GB", "Red"),
+    'MC526': ("iPod Nano", "6th Gen", "16GB", "Silver"),
+    'MC694': ("iPod Nano", "6th Gen", "16GB", "Graphite"),
+    'MC695': ("iPod Nano", "6th Gen", "16GB", "Blue"),
+    'MC696': ("iPod Nano", "6th Gen", "16GB", "Green"),
+    'MC697': ("iPod Nano", "6th Gen", "16GB", "Orange"),
+    'MC698': ("iPod Nano", "6th Gen", "16GB", "Pink"),
+    'MC699': ("iPod Nano", "6th Gen", "16GB", "Red"),
+
+    # ==========================================================================
+    # iPod Nano — 7th Generation (2012)
+    # ==========================================================================
+    'MD475': ("iPod Nano", "7th Gen", "16GB", "Pink"),
+    'MD476': ("iPod Nano", "7th Gen", "16GB", "Yellow"),
+    'MD477': ("iPod Nano", "7th Gen", "16GB", "Blue"),
+    'MD478': ("iPod Nano", "7th Gen", "16GB", "Green"),
+    'MD479': ("iPod Nano", "7th Gen", "16GB", "Purple"),
+    'MD480': ("iPod Nano", "7th Gen", "16GB", "Silver"),
+    'MD481': ("iPod Nano", "7th Gen", "16GB", "Slate"),
+    'MD744': ("iPod Nano", "7th Gen", "16GB", "Red"),
+    'ME971': ("iPod Nano", "7th Gen", "16GB", "Space Gray"),
+    'MKMV2': ("iPod Nano", "7th Gen", "16GB", "Pink"),
+    'MKMX2': ("iPod Nano", "7th Gen", "16GB", "Gold"),
+    'MKN02': ("iPod Nano", "7th Gen", "16GB", "Blue"),
+    'MKN22': ("iPod Nano", "7th Gen", "16GB", "Silver"),
+    'MKN52': ("iPod Nano", "7th Gen", "16GB", "Space Gray"),
+    'MKN72': ("iPod Nano", "7th Gen", "16GB", "Red"),
+
+    # ==========================================================================
+    # iPod Shuffle — 1st Generation (2005)
+    # ==========================================================================
+    'M9724': ("iPod Shuffle", "1st Gen", "512MB", "White"),
+    'M9725': ("iPod Shuffle", "1st Gen", "1GB", "White"),
+
+    # ==========================================================================
+    # iPod Shuffle — 2nd Generation (2006-2008)
+    # ==========================================================================
+    'MA546': ("iPod Shuffle", "2nd Gen", "1GB", "Silver"),
+    'MA564': ("iPod Shuffle", "2nd Gen", "1GB", "Silver"),
+    'MA947': ("iPod Shuffle", "2nd Gen", "1GB", "Pink"),
+    'MA949': ("iPod Shuffle", "2nd Gen", "1GB", "Blue"),
+    'MA951': ("iPod Shuffle", "2nd Gen", "1GB", "Green"),
+    'MA953': ("iPod Shuffle", "2nd Gen", "1GB", "Orange"),
+    'MB225': ("iPod Shuffle", "2nd Gen", "1GB", "Silver"),
+    'MB227': ("iPod Shuffle", "2nd Gen", "1GB", "Blue"),
+    'MB228': ("iPod Shuffle", "2nd Gen", "1GB", "Blue"),
+    'MB229': ("iPod Shuffle", "2nd Gen", "1GB", "Green"),
+    'MB231': ("iPod Shuffle", "2nd Gen", "1GB", "Red"),
+    'MB233': ("iPod Shuffle", "2nd Gen", "1GB", "Purple"),
+    'MB518': ("iPod Shuffle", "2nd Gen", "2GB", "Silver"),
+    'MB520': ("iPod Shuffle", "2nd Gen", "2GB", "Blue"),
+    'MB522': ("iPod Shuffle", "2nd Gen", "2GB", "Green"),
+    'MB524': ("iPod Shuffle", "2nd Gen", "2GB", "Red"),
+    'MB526': ("iPod Shuffle", "2nd Gen", "2GB", "Purple"),
+    'MB811': ("iPod Shuffle", "2nd Gen", "1GB", "Pink"),
+    'MB813': ("iPod Shuffle", "2nd Gen", "1GB", "Blue"),
+    'MB815': ("iPod Shuffle", "2nd Gen", "1GB", "Green"),
+    'MB817': ("iPod Shuffle", "2nd Gen", "1GB", "Red"),
+    'MB681': ("iPod Shuffle", "2nd Gen", "2GB", "Pink"),
+    'MB683': ("iPod Shuffle", "2nd Gen", "2GB", "Blue"),
+    'MB685': ("iPod Shuffle", "2nd Gen", "2GB", "Green"),
+    'MB779': ("iPod Shuffle", "2nd Gen", "2GB", "Red"),
+    'MC167': ("iPod Shuffle", "2nd Gen", "1GB", "Gold"),
+
+    # ==========================================================================
+    # iPod Shuffle — 3rd Generation (2009)
+    # ==========================================================================
+    'MB867': ("iPod Shuffle", "3rd Gen", "4GB", "Silver"),
+    'MC164': ("iPod Shuffle", "3rd Gen", "4GB", "Black"),
+    'MC306': ("iPod Shuffle", "3rd Gen", "2GB", "Silver"),
+    'MC323': ("iPod Shuffle", "3rd Gen", "2GB", "Black"),
+    'MC381': ("iPod Shuffle", "3rd Gen", "2GB", "Green"),
+    'MC384': ("iPod Shuffle", "3rd Gen", "2GB", "Blue"),
+    'MC387': ("iPod Shuffle", "3rd Gen", "2GB", "Pink"),
+    'MC303': ("iPod Shuffle", "3rd Gen", "4GB", "Stainless Steel"),
+    'MC307': ("iPod Shuffle", "3rd Gen", "4GB", "Green"),
+    'MC328': ("iPod Shuffle", "3rd Gen", "4GB", "Blue"),
+    'MC331': ("iPod Shuffle", "3rd Gen", "4GB", "Pink"),
+
+    # ==========================================================================
+    # iPod Shuffle — 4th Generation (2010-2015)
+    # ==========================================================================
+    'MC584': ("iPod Shuffle", "4th Gen", "2GB", "Silver"),
+    'MC585': ("iPod Shuffle", "4th Gen", "2GB", "Pink"),
+    'MC749': ("iPod Shuffle", "4th Gen", "2GB", "Orange"),
+    'MC750': ("iPod Shuffle", "4th Gen", "2GB", "Green"),
+    'MC751': ("iPod Shuffle", "4th Gen", "2GB", "Blue"),
+    'MD773': ("iPod Shuffle", "4th Gen", "2GB", "Pink"),
+    'MD774': ("iPod Shuffle", "4th Gen", "2GB", "Yellow"),
+    'MD775': ("iPod Shuffle", "4th Gen", "2GB", "Blue"),
+    'MD776': ("iPod Shuffle", "4th Gen", "2GB", "Green"),
+    'MD777': ("iPod Shuffle", "4th Gen", "2GB", "Purple"),
+    'MD778': ("iPod Shuffle", "4th Gen", "2GB", "Silver"),
+    'MD779': ("iPod Shuffle", "4th Gen", "2GB", "Slate"),
+    'MD780': ("iPod Shuffle", "4th Gen", "2GB", "Red"),
+    'ME949': ("iPod Shuffle", "4th Gen", "2GB", "Space Gray"),
+    'MKM72': ("iPod Shuffle", "4th Gen", "2GB", "Pink"),
+    'MKM92': ("iPod Shuffle", "4th Gen", "2GB", "Gold"),
+    'MKME2': ("iPod Shuffle", "4th Gen", "2GB", "Blue"),
+    'MKMG2': ("iPod Shuffle", "4th Gen", "2GB", "Silver"),
+    'MKMJ2': ("iPod Shuffle", "4th Gen", "2GB", "Space Gray"),
+    'MKML2': ("iPod Shuffle", "4th Gen", "2GB", "Red"),
+}
+
+
+# ╔═══════════════════════════════════════════════════════════════════════════╗
+# ║  USB Product ID → iPod generation (Apple VID = 0x05AC)                  ║
+# ╚═══════════════════════════════════════════════════════════════════════════╝
+
+USB_PID_TO_MODEL: dict[int, tuple[str, str]] = {
+    # ── Normal-mode PIDs (0x120x) ──────────────────────────────────────────
+    0x1201: ("iPod", "3rd Gen"),
+    0x1202: ("iPod", ""),  # 1st/2nd Gen share this PID in USB ID tables
+    0x1203: ("iPod", "4th Gen"),
+    0x1204: ("iPod Photo", "4th Gen"),
+    0x1205: ("iPod Mini", ""),  # Mini 1st/2nd Gen share this PID
+    0x1206: ("iPod", ""),       # USB IDs label this only as "iPod '06'"
+    0x1207: ("iPod", ""),       # USB IDs label this only as "iPod '07'"
+    0x1208: ("iPod", ""),       # USB IDs label this only as "iPod '08'"
+    0x1209: ("iPod Video", ""),  # 5th/5.5th Gen share this coarse PID
+    0x120A: ("iPod Nano", ""),  # Original nano-era generic PID
+
+    # ── DFU / WTF recovery mode PIDs (0x124x) ─────────────────────────────
+    0x1240: ("iPod Nano", "2nd Gen (Recovery)"),
+    0x1241: ("iPod Classic", "1st Gen (Recovery)"),
+    0x1242: ("iPod Nano", "3rd Gen (Recovery)"),
+    0x1243: ("iPod Nano", "4th Gen (Recovery)"),
+    0x1245: ("iPod Classic", "3rd Gen (Recovery)"),
+    0x1246: ("iPod Nano", "5th Gen (Recovery)"),
+    0x1255: ("iPod Nano", "4th Gen (Recovery)"),
+
+    # ── Normal-mode PIDs (0x126x) ──────────────────────────────────────────
+    0x1260: ("iPod Nano", "2nd Gen"),
+    0x1261: ("iPod Classic", ""),
+    0x1262: ("iPod Nano", "3rd Gen"),
+    0x1263: ("iPod Nano", "4th Gen"),
+    0x1265: ("iPod Nano", "5th Gen"),
+    0x1266: ("iPod Nano", "6th Gen"),
+    0x1267: ("iPod Nano", "7th Gen"),
+
+    # ── iPod Shuffle PIDs ──────────────────────────────────────────────────
+    0x1300: ("iPod Shuffle", "1st Gen"),
+    0x1301: ("iPod Shuffle", "2nd Gen"),
+    0x1302: ("iPod Shuffle", "3rd Gen"),
+    0x1303: ("iPod Shuffle", "4th Gen"),
+}
+
+IPOD_USB_PIDS: frozenset[int] = frozenset(USB_PID_TO_MODEL)
+
+
+# ╔═══════════════════════════════════════════════════════════════════════════╗
+# ║  Serial number last-3-char → model number (from libgpod)                ║
+# ╚═══════════════════════════════════════════════════════════════════════════╝
+
+SERIAL_LAST3_TO_MODEL: dict[str, str] = {
+    # ── iPod Classic ────────────────────────────────────────────────────
+    "Y5N": "MB029", "YMV": "MB147", "YMU": "MB145", "YMX": "MB150",
+    "2C5": "MB562", "2C7": "MB565",
+    "9ZS": "MC293", "9ZU": "MC297",
+    # ── iPod 1G (scroll wheel) ─────────────────────────────────────────
+    "LG6": "M8541", "NAM": "M8541", "MJ2": "M8541",
+    "ML1": "M8709", "MME": "M8709",
+    # ── iPod 2G (touch wheel) ──────────────────────────────────────────
+    "MMB": "M8737", "MMC": "M8738",
+    "NGE": "M8740", "NGH": "M8740", "MMF": "M8741",
+    # ── iPod 3G (dock connector) ───────────────────────────────────────
+    "NLW": "M8946", "NRH": "M8976", "QQF": "M9460",
+    "PQ5": "M9244", "PNT": "M9244", "NLY": "M8948", "NM7": "M8948",
+    "PNU": "M9245",
+    # ── iPod 4G (click wheel) ──────────────────────────────────────────
+    "PS9": "M9282", "Q8U": "M9282", "PQ7": "M9268",
+    # ── iPod U2 (4G click wheel, 20GB) ─────────────────────────────────
+    "S2X": "M9787",
+    # ── iPod Photo / Color Display ─────────────────────────────────────
+    "TDU": "MA079", "TDS": "MA079", "TM2": "MA127",
+    "SAZ": "M9830", "SB1": "M9830", "SAY": "M9829",
+    "R5Q": "M9585", "R5R": "M9586", "R5T": "M9586",
+    # ── iPod Mini 1G ───────────────────────────────────────────────────
+    "PFW": "M9160", "PRC": "M9160",
+    "QKL": "M9436", "QKQ": "M9436", "QKK": "M9435", "QKP": "M9435",
+    "QKJ": "M9434", "QKN": "M9434", "QKM": "M9437", "QKR": "M9437",
+    # ── iPod Mini 2G ───────────────────────────────────────────────────
+    "S41": "M9800", "S4C": "M9800", "S43": "M9802", "S45": "M9804", "S4G": "M9804",
+    "S47": "M9806", "S4J": "M9806", "S42": "M9801", "S44": "M9803",
+    "S48": "M9807",
+    # ── Shuffle 1G ─────────────────────────────────────────────────────
+    "RS9": "M9724", "QGV": "M9724", "TSX": "M9724", "PFV": "M9724",
+    "R80": "M9724", "RSA": "M9725", "TSY": "M9725", "C60": "M9725",
+    # ── Shuffle 2G ─────────────────────────────────────────────────────
+    "VTE": "MA546", "VTF": "MA546",
+    "XQ5": "MA947", "XQS": "MA947", "XQV": "MA949", "XQX": "MA949",
+    "YX7": "MB228", "XQY": "MA951", "YX8": "MA951", "XR1": "MA953",
+    "YXA": "MB233", "YX6": "MB225", "YX9": "MB225",
+    "8CQ": "MC167", "1ZH": "MB518",
+    # ── Shuffle 3G ─────────────────────────────────────────────────────
+    "A1S": "MC306", "A78": "MC323", "ALB": "MC381", "ALD": "MC384",
+    "ALG": "MC387", "4NZ": "MB867", "891": "MC164",
+    "A1L": "MC303", "A1U": "MC307", "A7B": "MC328", "A7D": "MC331",
+    # ── Shuffle 4G ─────────────────────────────────────────────────────
+    "CMJ": "MC584", "CMK": "MC585", "FDM": "MC749", "FDN": "MC750",
+    "FDP": "MC751",
+    # ── Nano 1G ────────────────────────────────────────────────────────
+    "TUZ": "MA004", "TV0": "MA005", "TUY": "MA099", "TV1": "MA107",
+    "UYN": "MA350", "UYP": "MA352",
+    "UNA": "MA350", "UNB": "MA350", "UPR": "MA352", "UPS": "MA352",
+    "SZB": "MA004", "SZV": "MA004", "SZW": "MA004",
+    "SZC": "MA005", "SZT": "MA005",
+    "TJT": "MA099", "TJU": "MA099", "TK2": "MA107", "TK3": "MA107",
+    # ── Nano 2G ────────────────────────────────────────────────────────
+    "VQ5": "MA477", "VQ6": "MA477",
+    "V8T": "MA426", "V8U": "MA426",
+    "V8W": "MA428", "V8X": "MA428",
+    "VQH": "MA487", "VQJ": "MA487",
+    "VQK": "MA489", "VQL": "MA489", "VKL": "MA489",
+    "WL2": "MA725", "WL3": "MA725",
+    "X9A": "MA726", "X9B": "MA726",
+    "VQT": "MA497", "VQU": "MA497",
+    "YER": "MA899", "YES": "MA899",
+    # ── Nano 3G ────────────────────────────────────────────────────────
+    "Y0P": "MA978", "Y0R": "MA980",
+    "YXR": "MB249", "YXV": "MB257", "YXT": "MB253", "YXX": "MB261",
+    # ── Nano 4G ────────────────────────────────────────────────────────
+    "37P": "MB663", "37Q": "MB666", "37H": "MB654", "1P1": "MB480",
+    "37K": "MB657", "37L": "MB660", "2ME": "MB598",
+    "3QS": "MB732", "3QT": "MB735", "3QU": "MB739", "3QW": "MB742",
+    "3QX": "MB745", "3QY": "MB748", "3R0": "MB754", "3QZ": "MB751",
+    "5B7": "MB903", "5B8": "MB905", "5B9": "MB907", "5BA": "MB909",
+    "5BB": "MB911", "5BC": "MB913", "5BD": "MB915", "5BE": "MB917",
+    "5BF": "MB918",
+    # ── Nano 5G ────────────────────────────────────────────────────────
+    "71V": "MC027", "71Y": "MC031", "721": "MC034", "726": "MC037",
+    "72A": "MC040", "72F": "MC046", "72K": "MC049", "72L": "MC050",
+    "72Q": "MC060", "72R": "MC062",
+    "72S": "MC064", "72X": "MC066", "734": "MC068", "738": "MC070",
+    "739": "MC072", "73A": "MC074", "73B": "MC075",
+    # ── Nano 6G ────────────────────────────────────────────────────────
+    "CMN": "MC525", "CMP": "MC526",
+    "DVX": "MC688", "DVY": "MC689", "DW0": "MC690", "DW1": "MC691",
+    "DW2": "MC692", "DW3": "MC693",
+    "DW4": "MC694", "DW5": "MC695", "DW6": "MC696", "DW7": "MC697",
+    "DW8": "MC698", "DW9": "MC699",
+    # ── Nano 7G ────────────────────────────────────────────────────────
+    # Source: TheAppleWiki Models/iPod (serial suffix table). Entries there
+    # are 4-char suffixes (e.g. F0GN); this map stores last-3 to match our
+    # lookup_by_serial(serial[-3:]) convention.
+    "0GD": "MD475", "0GM": "MD475",  # pink
+    "0GF": "MD476", "0GN": "MD476",  # yellow
+    "0GG": "MD477", "0GP": "MD477",  # blue
+    "0GH": "MD478", "0GQ": "MD478",  # green
+    "0GJ": "MD479", "0GR": "MD479",  # purple
+    "0GK": "MD480", "0GT": "MD480",  # silver
+    "0GL": "MD481", "0GV": "MD481",  # slate
+    "4LN": "MD744", "4LP": "MD744",  # product red
+    "JQ1": "ME971",  # space gray (2013)
+    "K60": "MKMV2",  # pink (2015)
+    "K61": "MKMX2",  # gold (2015)
+    "K62": "MKN02",  # blue (2015)
+    "K63": "MKN22",  # silver (2015)
+    "K64": "MKN52",  # space gray (2015)
+    "K65": "MKN72",  # product red (2015)
+    # ── Video 5G ───────────────────────────────────────────────────────
+    "SZ9": "MA002", "WEC": "MA002", "WED": "MA002", "WEG": "MA002",
+    "WEH": "MA002", "WEL": "MA002",
+    "TXK": "MA146", "TXM": "MA146", "WEF": "MA146",
+    "WEJ": "MA146", "WEK": "MA146",
+    "SZA": "MA003", "SZU": "MA003", "TXL": "MA147", "TXN": "MA147",
+    "V9V": "MA452",  # iPod Video U2 Special Edition 5G 30GB (Black)
+    # ── Video 5.5G ─────────────────────────────────────────────────────
+    "V9K": "MA444", "V9L": "MA444", "WU9": "MA444",
+    "VQM": "MA446", "V9M": "MA446", "V9N": "MA446", "WEE": "MA446",
+    "V9P": "MA448", "V9Q": "MA448",
+    "V9R": "MA450", "V9S": "MA450", "V95": "MA450",
+    "V96": "MA450", "WUC": "MA450",
+    "W9G": "MA664",
+}

src/vendor/ipod_device/sysinfo.py

@@ -0,0 +1,528 @@
+"""
+Parsing and evidence helpers for iPod SysInfo and SysInfoExtended data.
+
+This module intentionally contains no hardware probing.  It accepts bytes or
+text gathered from files, SCSI VPD, or USB vendor-control reads and turns them
+into source-tagged identity/capability data that the scanner and DeviceInfo
+enrichment code can consume consistently.
+"""
+
+from __future__ import annotations
+
+import plistlib
+import re
+from collections.abc import Iterable
+from dataclasses import dataclass, field
+from typing import Any
+
+COVER_ART_KEYS: tuple[str, ...] = (
+    "AlbumArt",
+    "AlbumArt2",
+    "ArtworkFormats",
+    "CoverArt",
+    "ArtworkCoverArtFormats",
+)
+
+PHOTO_ART_KEYS: tuple[str, ...] = (
+    "ImageSpecifications",
+    "PhotoFormats",
+)
+
+CHAPTER_ART_KEYS: tuple[str, ...] = (
+    "ChapterImageSpecs",
+    "ChapterImageSpecifications",
+)
+
+
+@dataclass(frozen=True)
+class EvidenceValue:
+    """One resolved value with provenance."""
+
+    value: Any
+    source: str
+    live: bool = False
+    raw_key: str = ""
+
+
+@dataclass
+class DeviceEvidence:
+    """Small source-tagged container for identity and capability evidence."""
+
+    fields: dict[str, EvidenceValue] = field(default_factory=dict)
+    blobs: dict[str, Any] = field(default_factory=dict)
+
+    def add(
+        self,
+        field_name: str,
+        value: Any,
+        source: str,
+        *,
+        live: bool = False,
+        raw_key: str = "",
+        replace: bool = False,
+    ) -> None:
+        if value in (None, "", b""):
+            return
+        if field_name in self.fields and not replace:
+            return
+        self.fields[field_name] = EvidenceValue(
+            value=value,
+            source=source,
+            live=live,
+            raw_key=raw_key,
+        )
+
+    def as_flat_dict(self) -> dict[str, Any]:
+        result: dict[str, Any] = {k: v.value for k, v in self.fields.items()}
+        result["_sources"] = {k: v.source for k, v in self.fields.items()}
+        return result
+
+
+@dataclass
+class ParsedSysInfoExtended:
+    """Parsed representation of a SysInfoExtended XML/plist blob."""
+
+    plist: dict[str, Any]
+    raw_xml: bytes = b""
+    source: str = "sysinfo_extended"
+    live: bool = False
+    used_regex_fallback: bool = False
+
+    @property
+    def identity(self) -> dict[str, Any]:
+        return identity_from_sysinfo_extended(self, self.source, live=self.live)
+
+    @property
+    def cover_art_formats(self) -> dict[int, tuple[int, int]]:
+        return extract_image_formats(self.plist, COVER_ART_KEYS)
+
+    @property
+    def photo_formats(self) -> dict[int, tuple[int, int]]:
+        return extract_image_formats(self.plist, PHOTO_ART_KEYS)
+
+    @property
+    def chapter_image_formats(self) -> dict[int, tuple[int, int]]:
+        return extract_image_formats(self.plist, CHAPTER_ART_KEYS)
+
+
+def normalize_guid(value: Any) -> str:
+    """Return a compact uppercase 16-hex GUID-ish string, or empty string."""
+    if value is None:
+        return ""
+    guid = str(value).strip().replace(" ", "")
+    if guid.startswith(("0x", "0X")):
+        guid = guid[2:]
+    if not guid or guid == "0" * len(guid):
+        return ""
+    try:
+        bytes.fromhex(guid)
+    except ValueError:
+        return ""
+    return guid.upper()
+
+
+def _coerce_int(value: Any) -> int | str:
+    if value in (None, ""):
+        return 0
+    if isinstance(value, bool):
+        return int(value)
+    if isinstance(value, int):
+        return value
+    text = str(value).strip()
+    if not text:
+        return 0
+    # SysInfo often stores values like "0x00000003" or
+    # "0x00000003 (3.0 0)"; only the leading numeric token matters.
+    token = text.split(None, 1)[0]
+    try:
+        return int(token, 0)
+    except ValueError:
+        return text
+
+
+def _coerce_bool(value: Any) -> bool:
+    if isinstance(value, bool):
+        return value
+    if isinstance(value, (int, float)):
+        return bool(value)
+    text = str(value).strip().casefold()
+    return text in {"1", "true", "yes", "y", "on"}
+
+
+def parse_sysinfo_text(content: str) -> dict[str, str]:
+    """Parse plain SysInfo key/value text."""
+    result: dict[str, str] = {}
+    for line in content.splitlines():
+        line = line.strip()
+        if not line or line.startswith("#") or ":" not in line:
+            continue
+        key, value = line.split(":", 1)
+        result[key.strip()] = value.strip()
+    return result
+
+
+def identity_from_sysinfo(
+    sysinfo: dict[str, str],
+    source: str = "sysinfo",
+) -> dict[str, Any]:
+    """Return normalized DeviceInfo-style fields from a SysInfo dict."""
+    result: dict[str, Any] = {"_sources": {}}
+    sources: dict[str, str] = result["_sources"]
+
+    board = sysinfo.get("BoardHwName", "")
+    if board:
+        result["board"] = board
+        sources["board"] = source
+
+    serial = sysinfo.get("pszSerialNumber", "").strip()
+    if serial:
+        result["serial"] = serial
+        sources["serial"] = source
+
+    guid = normalize_guid(sysinfo.get("FirewireGuid", ""))
+    if guid:
+        result["firewire_guid"] = guid
+        sources["firewire_guid"] = source
+
+    firmware = (
+        sysinfo.get("visibleBuildID")
+        or sysinfo.get("VisibleBuildID")
+        or sysinfo.get("BuildID")
+        or ""
+    )
+    if firmware:
+        result["firmware"] = firmware
+        sources["firmware"] = source
+
+    raw_model = sysinfo.get("ModelNumStr", "")
+    if raw_model:
+        try:
+            from .lookup import extract_model_number
+
+            model_number = extract_model_number(raw_model)
+        except Exception:
+            model_number = raw_model.strip()
+        if model_number:
+            result["model_raw"] = raw_model
+            result["model_number"] = model_number
+            sources["model_number"] = source
+
+    for key, field_name in (
+        ("ModelFamily", "model_family"),
+        ("Generation", "generation"),
+        ("Capacity", "capacity"),
+        ("Color", "color"),
+    ):
+        value = sysinfo.get(key, "")
+        if value:
+            result[field_name] = value
+            sources[field_name] = source
+
+    pid = sysinfo.get("USBProductID", "")
+    if pid:
+        try:
+            result["usb_pid"] = int(pid, 0)
+            sources["usb_pid"] = source
+        except ValueError:
+            pass
+
+    for keys, field_name in (
+        (("FamilyID", "iPodFamily"), "family_id"),
+        (("UpdaterFamilyID",), "updater_family_id"),
+    ):
+        value = next((sysinfo.get(key) for key in keys if key in sysinfo), None)
+        if value not in (None, ""):
+            result[field_name] = _coerce_int(value)
+            sources[field_name] = source
+
+    return result
+
+
+def parse_sysinfo_extended(
+    content: bytes | str,
+    *,
+    source: str = "sysinfo_extended",
+    live: bool = False,
+) -> ParsedSysInfoExtended:
+    """Parse SysInfoExtended XML/plist data.
+
+    The same payload can come from an on-disk file, SCSI VPD pages, or Apple's
+    USB vendor-control command.  Some devices return leading/trailing bytes or
+    truncated XML; plist parsing is tried first, then a conservative regex
+    fallback extracts scalar fields.
+    """
+    if isinstance(content, str):
+        raw = content.encode("utf-8", errors="replace")
+    else:
+        raw = bytes(content)
+
+    raw = _extract_xml_bytes(raw)
+    plist: dict[str, Any] = {}
+    used_fallback = False
+
+    if raw:
+        parse_candidates = [raw]
+        if b"</plist>" not in raw:
+            parse_candidates.append(raw + b"\n</dict>\n</plist>")
+
+        for candidate in parse_candidates:
+            try:
+                parsed = plistlib.loads(candidate)
+            except Exception:
+                continue
+            if isinstance(parsed, dict):
+                plist = parsed
+                raw = candidate
+                break
+
+    if not plist:
+        plist = _parse_sysinfo_extended_regex(raw)
+        used_fallback = bool(plist)
+
+    return ParsedSysInfoExtended(
+        plist=plist,
+        raw_xml=raw,
+        source=source,
+        live=live,
+        used_regex_fallback=used_fallback,
+    )
+
+
+def identity_from_sysinfo_extended(
+    parsed: ParsedSysInfoExtended | dict[str, Any],
+    source: str = "sysinfo_extended",
+    *,
+    live: bool = False,
+) -> dict[str, Any]:
+    """Return normalized DeviceInfo-style fields from SysInfoExtended data."""
+    plist = parsed.plist if isinstance(parsed, ParsedSysInfoExtended) else parsed
+    result: dict[str, Any] = {"_sources": {}}
+    sources: dict[str, str] = result["_sources"]
+
+    def put(field_name: str, value: Any, raw_key: str = "") -> None:
+        if value in (None, ""):
+            return
+        result[field_name] = value
+        sources[field_name] = source
+
+    serial = str(plist.get("SerialNumber") or "").strip()
+    if serial and not serial.upper().startswith("RAND"):
+        put("serial", serial, "SerialNumber")
+
+    guid = normalize_guid(
+        plist.get("FireWireGUID")
+        or plist.get("FirewireGuid")
+        or plist.get("FireWireGuid")
+    )
+    if guid:
+        put("firewire_guid", guid, "FireWireGUID")
+
+    firmware = (
+        plist.get("FireWireVersion")
+        or plist.get("scsi_revision")
+        or plist.get("VisibleBuildID")
+        or plist.get("BuildID")
+        or plist.get("visibleBuildID")
+        or ""
+    )
+    if firmware:
+        put("firmware", str(firmware), "FireWireVersion")
+
+    board = plist.get("BoardHwName") or plist.get("BoardHwID") or ""
+    if board:
+        put("board", str(board), "BoardHwName")
+
+    raw_model = str(plist.get("ModelNumStr") or "").strip()
+    if raw_model:
+        try:
+            from .lookup import extract_model_number
+
+            model_number = extract_model_number(raw_model)
+        except Exception:
+            model_number = raw_model
+        if model_number:
+            result["model_raw"] = raw_model
+            put("model_number", model_number, "ModelNumStr")
+
+    for key, field_name in (
+        ("FamilyID", "family_id"),
+        ("UpdaterFamilyID", "updater_family_id"),
+        ("DBVersion", "db_version"),
+        ("ShadowDBVersion", "shadow_db_version"),
+        ("MaxTracks", "max_tracks"),
+        ("MaxTransferSpeed", "max_transfer_speed"),
+    ):
+        if key in plist:
+            put(field_name, _coerce_int(plist[key]), key)
+
+    for key, field_name in (
+        ("ProductType", "product_type"),
+        ("ConnectedBus", "connected_bus"),
+        ("VolumeFormat", "volume_format"),
+        ("scsi_vendor", "scsi_vendor"),
+        ("scsi_product", "scsi_product"),
+        ("scsi_revision", "scsi_revision"),
+        ("usb_serial", "usb_serial"),
+    ):
+        if key in plist:
+            put(field_name, str(plist[key]), key)
+
+    for key, field_name in (
+        ("usb_pid", "usb_pid"),
+        ("usb_vid", "usb_vid"),
+        ("MaxFileSizeInGB", "max_file_size_gb"),
+    ):
+        if key in plist:
+            put(field_name, _coerce_int(plist[key]), key)
+
+    for key, field_name in (
+        ("SQLiteDB", "uses_sqlite_db"),
+        ("SupportsSparseArtwork", "supports_sparse_artwork"),
+        ("PodcastsSupported", "podcasts_supported"),
+        ("VoiceMemosSupported", "voice_memos_supported"),
+    ):
+        if key in plist:
+            put(field_name, _coerce_bool(plist[key]), key)
+
+    for key, field_name in (
+        ("AudioCodecs", "audio_codecs"),
+        ("PowerInformation", "power_information"),
+        ("AppleDRMVersion", "apple_drm_version"),
+    ):
+        value = plist.get(key)
+        if isinstance(value, dict):
+            put(field_name, value, key)
+
+    artwork_formats = extract_image_formats(plist, COVER_ART_KEYS)
+    if artwork_formats:
+        result["artwork_formats"] = artwork_formats
+        sources["artwork_formats"] = source
+    photo_formats = extract_image_formats(plist, PHOTO_ART_KEYS)
+    if photo_formats:
+        result["photo_formats"] = photo_formats
+        sources["photo_formats"] = source
+    chapter_formats = extract_image_formats(plist, CHAPTER_ART_KEYS)
+    if chapter_formats:
+        result["chapter_image_formats"] = chapter_formats
+        sources["chapter_image_formats"] = source
+
+    if isinstance(parsed, ParsedSysInfoExtended):
+        if parsed.raw_xml:
+            result["sysinfo_extended_raw_xml"] = parsed.raw_xml
+        result["sysinfo_extended_used_regex_fallback"] = parsed.used_regex_fallback
+
+    return result
+
+
+def evidence_from_identity(
+    identity: dict[str, Any],
+    *,
+    source: str,
+    live: bool = False,
+) -> DeviceEvidence:
+    evidence = DeviceEvidence()
+    sources = identity.get("_sources", {})
+    for key, value in identity.items():
+        if key.startswith("_") or key in {"model_raw", "sysinfo_extended_raw_xml"}:
+            continue
+        evidence.add(
+            key,
+            value,
+            sources.get(key, source),
+            live=live,
+            replace=True,
+        )
+    return evidence
+
+
+def extract_image_formats(
+    plist: dict[str, Any],
+    keys: Iterable[str] = COVER_ART_KEYS,
+) -> dict[int, tuple[int, int]]:
+    """Extract image format IDs and dimensions from SysInfoExtended plist data."""
+    entries: list[Any] = []
+    for key in keys:
+        value = plist.get(key)
+        if isinstance(value, list):
+            entries.extend(value)
+
+    formats: dict[int, tuple[int, int]] = {}
+    for entry in entries:
+        if not isinstance(entry, dict):
+            continue
+
+        fmt_id = (
+            entry.get("FormatId")
+            or entry.get("CorrelationID")
+            or entry.get("format_id")
+        )
+        if fmt_id is None:
+            continue
+
+        width = (
+            entry.get("RenderWidth")
+            or entry.get("DisplayWidth")
+            or entry.get("Width")
+            or entry.get("width")
+        )
+        height = (
+            entry.get("RenderHeight")
+            or entry.get("DisplayHeight")
+            or entry.get("Height")
+            or entry.get("height")
+        )
+        if width is None or height is None:
+            continue
+
+        try:
+            fmt_int = int(fmt_id)
+            width_int = int(width)
+            height_int = int(height)
+        except (TypeError, ValueError):
+            continue
+
+        if fmt_int > 0 and width_int > 0 and height_int > 0:
+            formats[fmt_int] = (width_int, height_int)
+
+    return formats
+
+
+def _extract_xml_bytes(raw: bytes) -> bytes:
+    raw = bytes(raw or b"").strip(b"\x00\r\n\t ")
+    if not raw:
+        return b""
+    for marker in (b"<?xml", b"<plist"):
+        idx = raw.find(marker)
+        if idx >= 0:
+            raw = raw[idx:]
+            break
+    return raw.rstrip(b"\x00")
+
+
+def _parse_sysinfo_extended_regex(raw: bytes) -> dict[str, Any]:
+    text = raw.decode("utf-8", errors="replace")
+    result: dict[str, Any] = {}
+
+    for match in re.finditer(
+        r"<key>([^<]+)</key>\s*"
+        r"(?:(<string>(.*?)</string>)|(<integer>(.*?)</integer>)|"
+        r"(<true\s*/>)|(<false\s*/>))",
+        text,
+        flags=re.DOTALL,
+    ):
+        key = match.group(1).strip()
+        string_val = match.group(3)
+        int_val = match.group(5)
+        if string_val is not None:
+            result[key] = string_val.strip()
+        elif int_val is not None:
+            try:
+                result[key] = int(int_val.strip(), 0)
+            except ValueError:
+                result[key] = int_val.strip()
+        elif match.group(6) is not None:
+            result[key] = True
+        elif match.group(7) is not None:
+            result[key] = False
+
+    return result

src/vendor/ipod_device/usb_backend.py

@@ -0,0 +1,132 @@
+"""
+PyUSB backend resolution helpers.
+
+PyUSB is pure Python, but on Windows it still needs a native
+``libusb-1.0.dll``.  The app vendors the official 64-bit libusb DLL under
+``vendor/libusb/windows/x64`` and falls back to system/package locations.
+"""
+
+from __future__ import annotations
+
+import ctypes.util
+import logging
+import os
+import platform
+import sys
+from collections.abc import Callable
+from pathlib import Path
+
+logger = logging.getLogger(__name__)
+
+
+def get_libusb_backend():
+    """Return a PyUSB libusb1 backend, or ``None`` if no backend can load."""
+    try:
+        import usb.backend.libusb1
+    except ImportError:
+        return None
+
+    backend = usb.backend.libusb1.get_backend()
+    if backend is not None:
+        return backend
+
+    for candidate in _candidate_libusb_paths():
+        backend = _backend_from_path(usb.backend.libusb1.get_backend, candidate)
+        if backend is not None:
+            logger.debug("PyUSB libusb backend loaded from %s", candidate)
+            return backend
+
+    return None
+
+
+def backend_diagnostic() -> str:
+    """Return a short human-readable backend diagnostic string."""
+    try:
+        import usb.backend.libusb1
+    except ImportError:
+        return "pyusb is not installed"
+
+    if usb.backend.libusb1.get_backend() is not None:
+        return "system libusb backend available"
+
+    candidates = list(_candidate_libusb_paths())
+    if not candidates:
+        return "no libusb-1.0 library candidates found"
+
+    existing = [str(path) for path in candidates if path.exists()]
+    if existing:
+        return "libusb candidates exist but failed to load: " + ", ".join(existing)
+    return "libusb candidates missing: " + ", ".join(str(path) for path in candidates)
+
+
+def _backend_from_path(get_backend: Callable, path: Path):
+    if not path.exists():
+        return None
+
+    def _find_library(_name: str) -> str:
+        return str(path)
+
+    try:
+        return get_backend(find_library=_find_library)
+    except Exception as exc:
+        logger.debug("PyUSB backend load failed from %s: %s", path, exc)
+        return None
+
+
+def _candidate_libusb_paths() -> list[Path]:
+    candidates: list[Path] = []
+
+    for env_name in ("IOPENPOD_LIBUSB_DLL", "PYUSB_LIBUSB_DLL"):
+        env_path = os.environ.get(env_name, "").strip()
+        if env_path:
+            candidates.append(Path(env_path))
+
+    # Optional helper from the ``libusb-package`` wheel when available.
+    try:
+        import libusb_package  # type: ignore
+
+        path = libusb_package.find_library()
+        if path:
+            candidates.append(Path(path))
+    except Exception:
+        pass
+
+    system_path = ctypes.util.find_library("usb-1.0")
+    if system_path:
+        candidates.append(Path(system_path))
+
+    root = Path(__file__).resolve().parent.parent
+    exe_dir = Path(sys.executable).resolve().parent
+    if sys.platform == "win32":
+        arch = platform.architecture()[0]
+        if arch == "64bit":
+            candidates.extend([
+                root / "vendor" / "libusb" / "windows" / "x64" / "libusb-1.0.dll",
+                exe_dir / "libusb-1.0.dll",
+                exe_dir / "vendor" / "libusb" / "windows" / "x64" / "libusb-1.0.dll",
+            ])
+        else:
+            candidates.extend([
+                root / "vendor" / "libusb" / "windows" / "x86" / "libusb-1.0.dll",
+                exe_dir / "libusb-1.0.dll",
+                exe_dir / "vendor" / "libusb" / "windows" / "x86" / "libusb-1.0.dll",
+            ])
+    elif sys.platform == "darwin":
+        candidates.extend([
+            root / "vendor" / "libusb" / "macos" / "libusb-1.0.dylib",
+            exe_dir / "libusb-1.0.dylib",
+        ])
+    else:
+        candidates.extend([
+            root / "vendor" / "libusb" / "linux" / "libusb-1.0.so",
+            exe_dir / "libusb-1.0.so",
+        ])
+
+    unique: list[Path] = []
+    seen: set[str] = set()
+    for candidate in candidates:
+        key = str(candidate).casefold()
+        if key not in seen:
+            unique.append(candidate)
+            seen.add(key)
+    return unique

src/vendor/ipod_device/virtual.py

@@ -0,0 +1,506 @@
+"""Virtual iPod metadata creation and loading.
+
+Virtual iPods are ordinary folders seeded with enough iPod identity metadata
+for the rest of iOpenPod to treat them like a selected device.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import secrets
+import shutil
+import string
+from datetime import UTC, datetime
+from pathlib import Path
+from typing import Any
+
+from .capabilities import capabilities_for_family_gen
+from .checksum import CHECKSUM_MHBD_SCHEME, ChecksumType
+from .info import DeviceInfo, resolve_itdb_path
+from .models import IPOD_MODELS, SERIAL_LAST3_TO_MODEL, USB_PID_TO_MODEL
+
+VIRTUAL_IPOD_INFO_FILENAME = "iPodInfo.json"
+_SCHEMA_VERSION = 1
+_SERIAL_ALPHABET = string.ascii_uppercase + string.digits
+
+
+def virtual_ipod_info_path(ipod_path: str | os.PathLike[str]) -> Path:
+    """Return the root-level metadata path for a virtual iPod."""
+
+    return Path(ipod_path) / VIRTUAL_IPOD_INFO_FILENAME
+
+
+def has_virtual_ipod_info(ipod_path: str | os.PathLike[str]) -> bool:
+    """Return whether *ipod_path* contains virtual iPod metadata."""
+
+    if not str(ipod_path):
+        return False
+    return virtual_ipod_info_path(ipod_path).is_file()
+
+
+def available_virtual_ipod_models() -> list[dict[str, str]]:
+    """Return model choices that can be backed by a known serial suffix."""
+
+    suffix_by_model = _serial_suffix_by_model()
+    rows: list[dict[str, str]] = []
+    for model_number, (family, generation, capacity, color) in IPOD_MODELS.items():
+        suffix = suffix_by_model.get(model_number)
+        if not suffix:
+            continue
+        rows.append(
+            {
+                "model_number": model_number,
+                "model_family": family,
+                "generation": generation,
+                "capacity": capacity,
+                "color": color,
+                "serial_suffix": suffix,
+                "display_name": _model_display_name(
+                    model_number,
+                    family,
+                    generation,
+                    capacity,
+                    color,
+                ),
+            }
+        )
+    return sorted(
+        rows,
+        key=lambda row: (
+            row["model_family"],
+            row["generation"],
+            row["capacity"],
+            row["color"],
+            row["model_number"],
+        ),
+    )
+
+
+def create_virtual_ipod(
+    ipod_path: str | os.PathLike[str],
+    model_number: str,
+    *,
+    ipod_name: str = "iPod",
+) -> DeviceInfo:
+    """Create a virtual iPod root and return its hydrated DeviceInfo."""
+
+    root = Path(ipod_path).expanduser().resolve()
+    if not model_number:
+        raise ValueError("Choose an iPod model")
+    if model_number not in IPOD_MODELS:
+        raise ValueError(f"Unknown iPod model: {model_number}")
+
+    suffix = _serial_suffix_by_model().get(model_number)
+    if not suffix:
+        raise ValueError(f"No known serial suffix for model {model_number}")
+
+    family, generation, capacity, color = IPOD_MODELS[model_number]
+    caps = capabilities_for_family_gen(family, generation)
+    checksum = caps.checksum if caps is not None else ChecksumType.NONE
+    firewire_guid = _generate_firewire_guid()
+    serial = _generate_serial(suffix)
+    hash_iv = secrets.token_bytes(16)
+    hash_rndpart = secrets.token_bytes(12)
+
+    _seed_ipod_layout(root, caps)
+
+    payload: dict[str, Any] = {
+        "schema_version": _SCHEMA_VERSION,
+        "created_by": "iOpenPod",
+        "created_at": datetime.now(UTC).isoformat(),
+        "ipod_name": ipod_name.strip() or "iPod",
+        "mount_name": root.name or "iPod",
+        "model_number": model_number,
+        "model_family": family,
+        "generation": generation,
+        "capacity": capacity,
+        "color": color,
+        "serial": serial,
+        "serial_suffix": suffix,
+        "firewire_guid": firewire_guid,
+        "firmware": _default_firmware(family, generation),
+        "board": _default_board_name(family, generation),
+        "family_id": _default_family_id(family),
+        "updater_family_id": _default_family_id(family),
+        "product_type": model_number,
+        "usb_vid": 0x05AC,
+        "usb_pid": _usb_pid_for_identity(family, generation),
+        "usb_serial": firewire_guid,
+        "connected_bus": "USB",
+        "volume_format": "FAT32",
+        "scsi_vendor": "Apple",
+        "scsi_product": "iPod",
+        "scsi_revision": _default_firmware(family, generation),
+        "checksum_type": int(checksum),
+        "hashing_scheme": CHECKSUM_MHBD_SCHEME.get(checksum, 0),
+        "hash_info_iv": hash_iv.hex().upper(),
+        "hash_info_rndpart": hash_rndpart.hex().upper(),
+        "db_version": caps.db_version if caps is not None else 0,
+        "shadow_db_version": caps.shadow_db_version if caps is not None else 0,
+        "uses_sqlite_db": caps.uses_sqlite_db if caps is not None else False,
+        "supports_sparse_artwork": (
+            caps.supports_sparse_artwork if caps is not None else False
+        ),
+        "podcasts_supported": caps.supports_podcast if caps is not None else True,
+        "voice_memos_supported": False,
+        "artwork_formats": _format_map(
+            caps.cover_art_formats if caps is not None else ()
+        ),
+        "photo_formats": _format_map(
+            caps.photo_formats if caps is not None else ()
+        ),
+        "chapter_image_formats": {},
+    }
+
+    _write_json(root, payload)
+    _write_virtual_sysinfo(root, payload)
+    _write_virtual_hash_info(root, firewire_guid, hash_iv, hash_rndpart)
+    ensure_virtual_itunes_database(root)
+    return load_virtual_ipod_info(root)
+
+
+def ensure_virtual_itunes_database(ipod_path: str | os.PathLike[str]) -> str | None:
+    """Create an empty iTunesDB/iTunesCDB for a virtual iPod if it is missing."""
+
+    root = Path(ipod_path).expanduser().resolve()
+    existing = resolve_itdb_path(str(root))
+    if existing:
+        return existing
+
+    info = load_virtual_ipod_info(root)
+    caps = capabilities_for_family_gen(info.model_family, info.generation)
+    _write_empty_itunes_database(
+        root,
+        caps,
+        ipod_name=info.ipod_name or "iPod",
+        device_info=info,
+    )
+    return resolve_itdb_path(str(root))
+
+
+def load_virtual_ipod_info(
+    ipod_path: str | os.PathLike[str],
+) -> DeviceInfo:
+    """Load a virtual iPod root into a normal DeviceInfo object."""
+
+    root = Path(ipod_path).expanduser().resolve()
+    path = virtual_ipod_info_path(root)
+    if not path.is_file():
+        raise FileNotFoundError(f"Virtual iPod metadata not found at {path}")
+
+    with path.open("r", encoding="utf-8") as handle:
+        payload = json.load(handle)
+    if not isinstance(payload, dict):
+        raise ValueError(f"Invalid virtual iPod metadata at {path}")
+
+    info = DeviceInfo(
+        path=str(root),
+        mount_name=str(payload.get("mount_name") or root.name or "iPod"),
+    )
+    info.ipod_name = str(payload.get("ipod_name") or "")
+    for field in (
+        "model_number",
+        "model_family",
+        "generation",
+        "capacity",
+        "color",
+        "firewire_guid",
+        "serial",
+        "firmware",
+        "board",
+        "product_type",
+        "connected_bus",
+        "volume_format",
+        "scsi_vendor",
+        "scsi_product",
+        "scsi_revision",
+    ):
+        value = payload.get(field)
+        if value not in (None, ""):
+            setattr(info, field, str(value))
+            info._field_sources[field] = VIRTUAL_IPOD_INFO_FILENAME
+
+    for field in (
+        "family_id",
+        "updater_family_id",
+        "usb_pid",
+        "usb_vid",
+        "db_version",
+        "shadow_db_version",
+        "checksum_type",
+        "hashing_scheme",
+    ):
+        raw_value = payload.get(field)
+        if raw_value not in (None, ""):
+            value = _coerce_int(raw_value)
+            setattr(info, field, value)
+            info._field_sources[field] = VIRTUAL_IPOD_INFO_FILENAME
+
+    for field in (
+        "uses_sqlite_db",
+        "supports_sparse_artwork",
+        "podcasts_supported",
+        "voice_memos_supported",
+    ):
+        if field in payload:
+            setattr(info, field, bool(payload.get(field)))
+            info._field_sources[field] = VIRTUAL_IPOD_INFO_FILENAME
+
+    info.usb_serial = str(payload.get("usb_serial") or info.firewire_guid or "")
+    if info.usb_serial:
+        info._field_sources["usb_serial"] = VIRTUAL_IPOD_INFO_FILENAME
+
+    info.hash_info_iv = _bytes_from_hex(payload.get("hash_info_iv"), 16)
+    info.hash_info_rndpart = _bytes_from_hex(payload.get("hash_info_rndpart"), 12)
+    if info.hash_info_iv:
+        info._field_sources["hash_info_iv"] = VIRTUAL_IPOD_INFO_FILENAME
+    if info.hash_info_rndpart:
+        info._field_sources["hash_info_rndpart"] = VIRTUAL_IPOD_INFO_FILENAME
+
+    info.artwork_formats = _coerce_format_map(payload.get("artwork_formats"))
+    info.photo_formats = _coerce_format_map(payload.get("photo_formats"))
+    info.chapter_image_formats = _coerce_format_map(
+        payload.get("chapter_image_formats")
+    )
+    for field in ("artwork_formats", "photo_formats", "chapter_image_formats"):
+        if getattr(info, field):
+            info._field_sources[field] = VIRTUAL_IPOD_INFO_FILENAME
+
+    caps = capabilities_for_family_gen(info.model_family, info.generation)
+    if caps is not None:
+        if not info.db_version:
+            info.db_version = caps.db_version
+        if info.checksum_type == 99:
+            info.checksum_type = int(caps.checksum)
+        if not info.artwork_formats:
+            info.artwork_formats = _format_map(caps.cover_art_formats)
+        if not info.photo_formats:
+            info.photo_formats = _format_map(caps.photo_formats)
+        info.shadow_db_version = info.shadow_db_version or caps.shadow_db_version
+        info.uses_sqlite_db = bool(info.uses_sqlite_db or caps.uses_sqlite_db)
+        info.supports_sparse_artwork = bool(
+            info.supports_sparse_artwork or caps.supports_sparse_artwork
+        )
+        info.podcasts_supported = bool(info.podcasts_supported or caps.supports_podcast)
+
+    try:
+        total_bytes, _used_bytes, free_bytes = shutil.disk_usage(root)
+        info.disk_size_gb = round(total_bytes / 1e9, 1)
+        info.free_space_gb = round(free_bytes / 1e9, 1)
+    except OSError:
+        pass
+
+    info.identification_method = "filesystem"
+    return info
+
+
+def _serial_suffix_by_model() -> dict[str, str]:
+    suffix_by_model: dict[str, str] = {}
+    for suffix, model_number in sorted(SERIAL_LAST3_TO_MODEL.items()):
+        suffix_by_model.setdefault(model_number, suffix)
+    return suffix_by_model
+
+
+def _model_display_name(
+    model_number: str,
+    family: str,
+    generation: str,
+    capacity: str,
+    color: str,
+) -> str:
+    parts = [family, generation, capacity, color]
+    return f"{' '.join(part for part in parts if part)} ({model_number})"
+
+
+def _generate_serial(suffix: str) -> str:
+    prefix = "".join(secrets.choice(_SERIAL_ALPHABET) for _ in range(8))
+    return prefix + suffix
+
+
+def _generate_firewire_guid() -> str:
+    while True:
+        guid = secrets.token_hex(8).upper()
+        if guid != "0" * 16:
+            return guid
+
+
+def _seed_ipod_layout(root: Path, caps: Any | None) -> None:
+    (root / "iPod_Control" / "Device").mkdir(parents=True, exist_ok=True)
+    (root / "iPod_Control" / "iTunes").mkdir(parents=True, exist_ok=True)
+    (root / "iPod_Control" / "Music").mkdir(parents=True, exist_ok=True)
+    (root / "iPod_Control" / "Artwork").mkdir(parents=True, exist_ok=True)
+    if caps is not None and caps.uses_sqlite_db:
+        (
+            root
+            / "iPod_Control"
+            / "iTunes"
+            / "iTunes Library.itlp"
+        ).mkdir(parents=True, exist_ok=True)
+
+
+def _write_json(root: Path, payload: dict[str, Any]) -> None:
+    with virtual_ipod_info_path(root).open("w", encoding="utf-8") as handle:
+        json.dump(payload, handle, indent=2, sort_keys=True)
+        handle.write("\n")
+
+
+def _write_virtual_sysinfo(root: Path, payload: dict[str, Any]) -> None:
+    sysinfo_path = root / "iPod_Control" / "Device" / "SysInfo"
+    fields = {
+        "ModelNumStr": payload.get("model_number", ""),
+        "FirewireGuid": payload.get("firewire_guid", ""),
+        "pszSerialNumber": payload.get("serial", ""),
+        "BoardHwName": payload.get("board", ""),
+        "visibleBuildID": payload.get("firmware", ""),
+        "ModelFamily": payload.get("model_family", ""),
+        "Generation": payload.get("generation", ""),
+        "Capacity": payload.get("capacity", ""),
+        "Color": payload.get("color", ""),
+        "USBProductID": _hex_int(payload.get("usb_pid")),
+        "FamilyID": _hex_int(payload.get("family_id")),
+        "UpdaterFamilyID": _hex_int(payload.get("updater_family_id")),
+    }
+    lines = [f"{key}: {value}" for key, value in fields.items() if value not in ("", None)]
+    sysinfo_path.write_text("\n".join(lines) + "\n", encoding="utf-8")
+
+
+def _write_virtual_hash_info(
+    root: Path,
+    firewire_guid: str,
+    hash_iv: bytes,
+    hash_rndpart: bytes,
+) -> None:
+    try:
+        from iTunesDB_Writer.hash72 import write_hash_info
+
+        uuid = bytearray(20)
+        guid_bytes = bytes.fromhex(firewire_guid)
+        uuid[: len(guid_bytes)] = guid_bytes
+        write_hash_info(str(root), bytes(uuid), hash_iv, hash_rndpart)
+    except Exception:
+        # The in-memory DeviceInfo carries the same values; this file is a
+        # compatibility cache for non-GUI write paths.
+        return
+
+
+def _write_empty_itunes_database(
+    root: Path,
+    caps: Any | None,
+    *,
+    ipod_name: str,
+    device_info: DeviceInfo,
+) -> None:
+    """Seed the virtual iPod with an empty database so normal loading succeeds."""
+
+    from iTunesDB_Writer import write_itunesdb
+
+    from .info import get_current_device, set_current_device
+
+    previous_device = get_current_device()
+    set_current_device(device_info)
+    try:
+        ok = write_itunesdb(
+            str(root),
+            [],
+            backup=False,
+            pc_file_paths=None,
+            capabilities=caps,
+            master_playlist_name=ipod_name,
+        )
+    finally:
+        set_current_device(previous_device)
+
+    if not ok:
+        raise RuntimeError("Failed to create an empty iTunesDB for the virtual iPod")
+
+
+def _default_firmware(family: str, generation: str) -> str:
+    if family == "iPod Classic":
+        return "2.0.5"
+    if family == "iPod Nano" and generation in {"5th Gen", "6th Gen", "7th Gen"}:
+        return "1.0.4"
+    if "Video" in family:
+        return "1.3"
+    return "1.0"
+
+
+def _default_board_name(family: str, generation: str) -> str:
+    text = f"{family} {generation}".strip()
+    return "".join(ch for ch in text if ch.isalnum()) or "iPod"
+
+
+def _default_family_id(family: str) -> int:
+    family_norm = family.casefold()
+    if "shuffle" in family_norm:
+        return 0x00000006
+    if "nano" in family_norm:
+        return 0x0000000A
+    if "classic" in family_norm:
+        return 0x0000000B
+    if "mini" in family_norm:
+        return 0x00000008
+    return 0x00000001
+
+
+def _usb_pid_for_identity(family: str, generation: str) -> int:
+    normal_pids = {
+        pid: identity
+        for pid, identity in USB_PID_TO_MODEL.items()
+        if not (0x1240 <= pid <= 0x1255)
+    }
+    for pid, (pid_family, pid_generation) in normal_pids.items():
+        if pid_family == family and pid_generation == generation:
+            return pid
+    for pid, (pid_family, pid_generation) in normal_pids.items():
+        if pid_family == family and not pid_generation:
+            return pid
+    return 0
+
+
+def _format_map(formats: Any) -> dict[int, tuple[int, int]]:
+    result: dict[int, tuple[int, int]] = {}
+    for fmt in formats or ():
+        fmt_id = int(fmt.format_id)
+        result[fmt_id] = (int(fmt.width), int(fmt.height))
+    return result
+
+
+def _coerce_format_map(value: Any) -> dict[int, tuple[int, int]]:
+    if not isinstance(value, dict):
+        return {}
+    result: dict[int, tuple[int, int]] = {}
+    for key, item in value.items():
+        try:
+            fmt_id = int(key)
+            width, height = item
+            result[fmt_id] = (int(width), int(height))
+        except (TypeError, ValueError):
+            continue
+    return result
+
+
+def _coerce_int(value: Any) -> int:
+    if isinstance(value, bool) or value in (None, ""):
+        return 0
+    if isinstance(value, int):
+        return value
+    try:
+        return int(str(value), 0)
+    except ValueError:
+        return 0
+
+
+def _bytes_from_hex(value: Any, expected_len: int) -> bytes:
+    if not value:
+        return b""
+    try:
+        data = bytes.fromhex(str(value))
+    except ValueError:
+        return b""
+    return data if len(data) == expected_len else b""
+
+
+def _hex_int(value: Any) -> str:
+    number = _coerce_int(value)
+    return f"0x{number:08X}" if number else ""

src/vendor/ipod_device/vpd_iokit.py

@@ -0,0 +1,617 @@
+"""
+macOS-only IOKit SCSI VPD query for iPods.
+
+Uses IOKit's SCSITaskLib CFPlugIn to send SCSI INQUIRY VPD commands
+directly to iPod hardware without requiring root, driver detach, or
+disk unmount.  Provides the same dict shape as vpd_libusb so
+ipod_device.info._enrich_from_usb_vpd can consume it unchanged.
+
+Requirements:  macOS only (IOKit framework).  No third-party packages.
+"""
+
+from __future__ import annotations
+
+import ctypes
+import logging
+import plistlib
+import re
+import struct
+import sys
+from ctypes import (
+    POINTER,
+    Structure,
+    byref,
+    c_char_p,
+    c_int32,
+    c_uint8,
+    c_uint32,
+    c_uint64,
+    c_void_p,
+    cast,
+    create_string_buffer,
+)
+
+if sys.platform != "darwin":
+    raise ImportError("ipod_device.vpd_iokit is macOS-only")
+
+log = logging.getLogger(__name__)
+
+# ── IOKit / CoreFoundation via ctypes ────────────────────────────────
+
+_cf = ctypes.cdll.LoadLibrary(
+    "/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation"
+)
+_iok = ctypes.cdll.LoadLibrary(
+    "/System/Library/Frameworks/IOKit.framework/IOKit"
+)
+
+# CFString helpers
+_cf.CFStringGetCString.argtypes = [c_void_p, c_char_p, c_int32, c_uint32]
+_cf.CFStringGetCString.restype = ctypes.c_bool
+_cf.CFRelease.argtypes = [c_void_p]
+_cf.CFRelease.restype = None
+_cf.CFGetTypeID.argtypes = [c_void_p]
+_cf.CFGetTypeID.restype = c_uint64
+_cf.CFStringGetTypeID.argtypes = []
+_cf.CFStringGetTypeID.restype = c_uint64
+_cf.CFNumberGetTypeID.argtypes = []
+_cf.CFNumberGetTypeID.restype = c_uint64
+_cf.CFNumberGetValue.argtypes = [c_void_p, c_int32, c_void_p]
+_cf.CFNumberGetValue.restype = ctypes.c_bool
+
+_cf.CFUUIDGetConstantUUIDWithBytes.restype = c_void_p
+_cf.CFUUIDGetConstantUUIDWithBytes.argtypes = [c_void_p] + [c_uint8] * 16
+
+_cf.CFStringCreateWithCString.argtypes = [c_void_p, c_char_p, c_uint32]
+_cf.CFStringCreateWithCString.restype = c_void_p
+kCFStringEncodingUTF8 = 0x08000100
+
+# IOKit registry
+_iok.IOServiceMatching.restype = c_void_p
+_iok.IOServiceMatching.argtypes = [c_char_p]
+_iok.IOServiceGetMatchingServices.argtypes = [c_uint32, c_void_p, POINTER(c_uint32)]
+_iok.IOServiceGetMatchingServices.restype = c_int32
+_iok.IOIteratorNext.argtypes = [c_uint32]
+_iok.IOIteratorNext.restype = c_uint32
+_iok.IOObjectRelease.argtypes = [c_uint32]
+_iok.IOObjectRelease.restype = c_int32
+_iok.IORegistryEntryGetParentEntry.argtypes = [c_uint32, c_char_p, POINTER(c_uint32)]
+_iok.IORegistryEntryGetParentEntry.restype = c_int32
+_iok.IORegistryEntryCreateCFProperty.argtypes = [c_uint32, c_void_p, c_void_p, c_uint32]
+_iok.IORegistryEntryCreateCFProperty.restype = c_void_p
+_iok.IORegistryEntryGetName.argtypes = [c_uint32, c_char_p]
+_iok.IORegistryEntryGetName.restype = c_int32
+
+_iok.IOCreatePlugInInterfaceForService.argtypes = [
+    c_uint32, c_void_p, c_void_p, POINTER(c_void_p), POINTER(c_int32)
+]
+_iok.IOCreatePlugInInterfaceForService.restype = c_int32
+
+kIOServicePlane = b"IOService"
+
+# ── UUIDs ────────────────────────────────────────────────────────────
+
+
+def _make_uuid(*b: int) -> c_void_p:
+    return _cf.CFUUIDGetConstantUUIDWithBytes(None, *[c_uint8(x) for x in b])
+
+
+_kSCSITaskDeviceUserClientTypeID = _make_uuid(
+    0x7D, 0x66, 0x67, 0x8E, 0x08, 0xA2, 0x11, 0xD5,
+    0xA1, 0xB8, 0x00, 0x30, 0x65, 0x7D, 0x05, 0x2A,
+)
+_kIOCFPlugInInterfaceID = _make_uuid(
+    0xC2, 0x44, 0xE8, 0x58, 0x10, 0x9C, 0x11, 0xD4,
+    0x91, 0xD4, 0x00, 0x50, 0xE4, 0xC6, 0x42, 0x6F,
+)
+# Actual SCSITaskDeviceInterfaceID (from binary disassembly — differs
+# from the documented kSCSITaskDeviceInterfaceID = 6BD48AE0-…).
+_kSCSITaskDeviceInterfaceID_bytes = bytes([
+    0x1B, 0xBC, 0x41, 0x32, 0x08, 0xA5, 0x11, 0xD5,
+    0x90, 0xED, 0x00, 0x30, 0x65, 0x7D, 0x05, 0x2A,
+])
+
+# ── SCSI structures ─────────────────────────────────────────────────
+
+
+class _IOVirtualRange(Structure):
+    _fields_ = [("address", c_uint64), ("length", c_uint64)]
+
+
+class _SCSISenseData(Structure):
+    _fields_ = [("data", c_uint8 * 18)]
+
+
+_kSCSIDataTransfer_FromTargetToInitiator = 2
+
+# ── COM vtable helpers ───────────────────────────────────────────────
+#
+# IOKit CFPlugIn interfaces use COM-style vtables:
+#   obj → *vtable → [NULL, QI, AddRef, Release, version(0x1), method5, ...]
+#
+# SCSITaskDeviceInterface vtable (slots 5–10):
+#   [5] IsExclusiveAccessAvailable  [6] AddCallbackDispatcherToRunLoop
+#   [7] RemoveCallbackDispatcherFromRunLoop  [8] ObtainExclusiveAccess
+#   [9] ReleaseExclusiveAccess  [10] CreateSCSITask
+#
+# SCSITaskInterface vtable (slots 5–24):
+#   [5] IsTaskActive  [6] SetTaskAttribute  [7] GetTaskAttribute
+#   [8] SetCommandDescriptorBlock(self, uint8*, uint8)
+#   [9] GetCommandDescriptorBlockSize  [10] GetCommandDescriptorBlock
+#   [11] SetScatterGatherEntries(self, IOVirtualRange*, uint8, uint64, uint8)
+#   [12] SetTimeoutDuration(self, uint32)
+#   [13] GetTimeoutDuration  [14] SetTaskCompletionCallback
+#   [15] ExecuteTaskAsync
+#   [16] ExecuteTaskSync(self, SenseData*, TaskStatus*, uint64*)
+#   [17] AbortTask  [18] GetServiceResponse  [19] GetTaskState
+#   [20] GetTaskStatus  [21] GetRealizedDataTransferCount
+#   [22] GetAutoSenseData  [23] SetSenseDataBuffer
+#   [24] ResetForNewTask
+
+
+def _vt_ptr(obj: c_void_p, slot: int):
+    """Return raw function pointer at vtable[slot]."""
+    vt_base = cast(obj, POINTER(c_void_p))[0]
+    return cast(vt_base, POINTER(c_void_p))[slot]
+
+
+def _vt_call(obj: c_void_p, slot: int, restype, argtypes, *args):
+    """Call vtable[slot](obj, *args)."""
+    fptr = _vt_ptr(obj, slot)
+    fn = ctypes.CFUNCTYPE(restype, c_void_p, *argtypes)(fptr)
+    return fn(obj, *args)
+
+
+# ── IOKit registry helpers ───────────────────────────────────────────
+
+def _cf_property_string(entry: int, key: str) -> str | None:
+    """Read a string property from an IOKit registry entry."""
+    cf_key = _cf.CFStringCreateWithCString(
+        None, key.encode(), kCFStringEncodingUTF8
+    )
+    if not cf_key:
+        return None
+    try:
+        cf_val = _iok.IORegistryEntryCreateCFProperty(entry, cf_key, None, 0)
+        if not cf_val:
+            return None
+        try:
+            if _cf.CFGetTypeID(cf_val) != _cf.CFStringGetTypeID():
+                return None
+            buf = ctypes.create_string_buffer(512)
+            if _cf.CFStringGetCString(cf_val, buf, 512, kCFStringEncodingUTF8):
+                return buf.value.decode("utf-8", errors="replace")
+            return None
+        finally:
+            _cf.CFRelease(cf_val)
+    finally:
+        _cf.CFRelease(cf_key)
+
+
+def _cf_property_int(entry: int, key: str) -> int | None:
+    """Read an integer property from an IOKit registry entry."""
+    cf_key = _cf.CFStringCreateWithCString(
+        None, key.encode(), kCFStringEncodingUTF8
+    )
+    if not cf_key:
+        return None
+    try:
+        cf_val = _iok.IORegistryEntryCreateCFProperty(entry, cf_key, None, 0)
+        if not cf_val:
+            return None
+        try:
+            if _cf.CFGetTypeID(cf_val) != _cf.CFNumberGetTypeID():
+                return None
+            val = c_int32(0)
+            # kCFNumberSInt32Type = 3
+            _cf.CFNumberGetValue(cf_val, 3, byref(val))
+            return val.value
+        finally:
+            _cf.CFRelease(cf_val)
+    finally:
+        _cf.CFRelease(cf_key)
+
+
+def _walk_parents_for_usb_info(service: int) -> dict:
+    """Walk IOKit registry parents to find USB device properties."""
+    result: dict = {}
+    entry = service
+    # Walk up to 10 levels — wrapped in try/finally so the last
+    # parent IOKit handle is always released even on unexpected errors.
+    try:
+        for _ in range(10):
+            parent = c_uint32(0)
+            kr = _iok.IORegistryEntryGetParentEntry(entry, kIOServicePlane, byref(parent))
+            if kr != 0:
+                break
+            # Check for USB device properties
+            pid = _cf_property_int(parent.value, "idProduct")
+            if pid is not None and "usb_pid" not in result:
+                result["usb_pid"] = pid
+            vid = _cf_property_int(parent.value, "idVendor")
+            if vid is not None and "usb_vid" not in result:
+                result["usb_vid"] = vid
+            serial = _cf_property_string(parent.value, "USB Serial Number")
+            if serial and "usb_serial" not in result:
+                result["usb_serial"] = serial
+            if entry != service:
+                _iok.IOObjectRelease(entry)
+            entry = parent.value
+            if "usb_pid" in result and "usb_serial" in result:
+                break
+    finally:
+        if entry != service:
+            try:
+                _iok.IOObjectRelease(entry)
+            except Exception:
+                pass
+    return result
+
+
+# ── SCSI command helpers ─────────────────────────────────────────────
+
+class _SCSISession:
+    """Manages exclusive access to one iPod's SCSI interface."""
+
+    def __init__(self, service: int):
+        self._service = service
+        self._plugin: c_void_p | None = None
+        self._device_if: c_void_p | None = None
+        self._task = None
+        self._exclusive = False
+
+    def open(self) -> bool:
+        """Create plugin → QueryInterface → ObtainExclusiveAccess → CreateTask."""
+        # 1. Create plugin
+        plugin = c_void_p(0)
+        score = c_int32(0)
+        kr = _iok.IOCreatePlugInInterfaceForService(
+            self._service,
+            _kSCSITaskDeviceUserClientTypeID,
+            _kIOCFPlugInInterfaceID,
+            byref(plugin),
+            byref(score),
+        )
+        if kr != 0:
+            log.debug("IOCreatePlugInInterfaceForService failed: 0x%08X", kr)
+            return False
+        self._plugin = plugin
+
+        # 2. QueryInterface for SCSITaskDeviceInterface
+        uuid_lo, uuid_hi = struct.unpack("<QQ", _kSCSITaskDeviceInterfaceID_bytes)
+        device_if = c_void_p(0)
+        hr = _vt_call(
+            plugin, 1, c_uint32,
+            [c_uint64, c_uint64, POINTER(c_void_p)],
+            c_uint64(uuid_lo), c_uint64(uuid_hi), byref(device_if),
+        )
+        if hr != 0:
+            log.debug("QueryInterface failed: 0x%08X", hr)
+            return False
+        self._device_if = device_if
+
+        # 3. ObtainExclusiveAccess [8]
+        kr = _vt_call(device_if, 8, c_int32, [])
+        if kr != 0:
+            log.debug("ObtainExclusiveAccess failed: 0x%08X", kr)
+            return False
+        self._exclusive = True
+
+        # 4. CreateSCSITask [10]
+        task = _vt_call(device_if, 10, c_void_p, [])
+        if not task:
+            log.debug("CreateSCSITask returned NULL")
+            return False
+        self._task = task
+        return True
+
+    def close(self):
+        """Release all resources.  Each step is guarded so a failure
+        in one does not prevent cleanup of the others."""
+        if self._task:
+            try:
+                _vt_call(c_void_p(self._task), 3, c_uint32, [])  # Release
+            except Exception:
+                log.debug("SCSISession: task Release failed", exc_info=True)
+            self._task = None
+        if self._exclusive and self._device_if:
+            try:
+                _vt_call(self._device_if, 9, c_int32, [])  # ReleaseExclusive
+            except Exception:
+                log.debug("SCSISession: ReleaseExclusive failed", exc_info=True)
+            self._exclusive = False
+        if self._device_if:
+            try:
+                _vt_call(self._device_if, 3, c_uint32, [])  # Release
+            except Exception:
+                log.debug("SCSISession: device_if Release failed", exc_info=True)
+            self._device_if = None
+        if self._plugin:
+            try:
+                _vt_call(self._plugin, 3, c_uint32, [])  # Release
+            except Exception:
+                log.debug("SCSISession: plugin Release failed", exc_info=True)
+            self._plugin = None
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *_):
+        self.close()
+
+    def inquiry(self, evpd: bool, page: int, alloc_len: int = 255) -> bytes | None:
+        """Send SCSI INQUIRY. Returns response bytes or None on failure."""
+        if not self._task:
+            return None
+
+        task = c_void_p(self._task)
+
+        # ResetForNewTask [24]
+        _vt_call(task, 24, c_int32, [])
+
+        # SetCDB [8]
+        cdb = (c_uint8 * 16)(
+            0x12,
+            0x01 if evpd else 0x00,
+            page & 0xFF,
+            0x00,
+            alloc_len & 0xFF,
+            0x00,
+            *([0] * 10),
+        )
+        kr = _vt_call(
+            task, 8, c_int32,
+            [POINTER(c_uint8), c_uint8],
+            cast(cdb, POINTER(c_uint8)), c_uint8(6),
+        )
+        if kr != 0:
+            return None
+
+        # SetScatterGatherEntries [11]
+        resp = create_string_buffer(alloc_len)
+        iovr = _IOVirtualRange(address=ctypes.addressof(resp), length=alloc_len)
+        kr = _vt_call(
+            task, 11, c_int32,
+            [POINTER(_IOVirtualRange), c_uint8, c_uint64, c_uint8],
+            byref(iovr), c_uint8(1), c_uint64(alloc_len),
+            c_uint8(_kSCSIDataTransfer_FromTargetToInitiator),
+        )
+        if kr != 0:
+            return None
+
+        # SetTimeoutDuration [12]
+        _vt_call(task, 12, c_int32, [c_uint32], c_uint32(10000))
+
+        # ExecuteTaskSync [16]
+        sense = _SCSISenseData()
+        status = c_uint32(0)
+        realized = c_uint64(0)
+        kr = _vt_call(
+            task, 16, c_int32,
+            [POINTER(_SCSISenseData), POINTER(c_uint32), POINTER(c_uint64)],
+            byref(sense), byref(status), byref(realized),
+        )
+        if kr != 0 or realized.value == 0:
+            return None
+
+        return bytes(resp)[: realized.value]
+
+
+# ── VPD parsing ──────────────────────────────────────────────────────
+
+def _read_vpd_pages(session: _SCSISession) -> bytes:
+    """Read and concatenate VPD data pages (0xC2+) from iPod."""
+    # Page 0xC0 lists the available data pages
+    data_pages: list[int] = []
+    c0 = session.inquiry(evpd=True, page=0xC0)
+    if c0 and len(c0) >= 4:
+        count = c0[3]
+        data_pages = [p for p in c0[4:4 + count] if p >= 0xC2]
+    if not data_pages:
+        # Fallback: try 0xC2–0xFF
+        data_pages = list(range(0xC2, 0x100))
+
+    raw = bytearray()
+    for page in data_pages:
+        resp = session.inquiry(evpd=True, page=page)
+        if not resp or len(resp) < 4:
+            continue
+        payload_len = resp[3]
+        payload = resp[4:4 + payload_len]
+        if not any(payload):
+            continue
+        raw.extend(payload)
+
+    # Strip trailing nulls
+    return bytes(raw).rstrip(b"\x00")
+
+
+def _parse_vpd_xml(raw: bytes) -> dict:
+    """Parse XML plist from concatenated VPD page data."""
+    result: dict = {}
+    if not raw:
+        return result
+
+    # Find XML start
+    for marker in (b"<?xml", b"<plist"):
+        idx = raw.find(marker)
+        if idx >= 0:
+            raw = raw[idx:]
+            break
+
+    # Ensure plist is closed (may be truncated)
+    if b"</plist>" not in raw:
+        raw = raw + b"\n</dict>\n</plist>"
+
+    try:
+        plist = plistlib.loads(raw)
+        if isinstance(plist, dict):
+            result = plist
+    except Exception:
+        # Fallback: regex extraction
+        result = _parse_vpd_regex(raw)
+
+    return result
+
+
+def _parse_vpd_regex(raw: bytes) -> dict:
+    """Regex fallback for truncated XML plists."""
+    result: dict = {}
+    text = raw.decode("utf-8", errors="replace")
+    for m in re.finditer(
+        r"<key>([^<]+)</key>\s*<(string|integer)>([^<]*)</\2>", text
+    ):
+        key, typ, val = m.group(1), m.group(2), m.group(3)
+        if typ == "integer":
+            try:
+                result[key] = int(val)
+            except ValueError:
+                result[key] = val
+        else:
+            result[key] = val
+    return result
+
+
+# ── Public API ───────────────────────────────────────────────────────
+
+def query_ipod_vpd(
+    usb_pid: int = 0, serial_filter: str = ""
+) -> dict | None:
+    """
+    Query a single iPod's device info via IOKit SCSI VPD.
+
+    No root required.  Does not detach the mass-storage driver or
+    unmount the iPod disk — the device stays mounted throughout.
+
+    Parameters
+    ----------
+    usb_pid : int
+        Target specific USB Product ID (0 = any).
+    serial_filter : str
+        Target specific USB serial / FireWire GUID (case-insensitive).
+
+    Returns
+    -------
+    dict or None
+        Keys include ``SerialNumber``, ``FireWireGUID``, ``FamilyID``,
+        ``UpdaterFamilyID``, ``vpd_raw_xml``, ``scsi_vendor``, etc.
+    """
+    match_dict = _iok.IOServiceMatching(b"com_apple_driver_iPodSBCNub")
+    if not match_dict:
+        return None
+    iterator = c_uint32(0)
+    kr = _iok.IOServiceGetMatchingServices(0, match_dict, byref(iterator))
+    if kr != 0:
+        return None
+
+    try:
+        while True:
+            svc = _iok.IOIteratorNext(iterator.value)
+            if svc == 0:
+                break
+            try:
+                result = _query_one_service(svc, usb_pid, serial_filter)
+                if result is not None:
+                    return result
+            except Exception as exc:
+                log.debug("Failed to query iPod service %d: %s", svc, exc)
+            finally:
+                _iok.IOObjectRelease(svc)
+    finally:
+        _iok.IOObjectRelease(iterator.value)
+
+    return None
+
+
+def query_all_ipods() -> list[dict]:
+    """
+    Query every connected iPod via IOKit SCSI VPD.
+
+    Returns a list of dicts (same format as ``query_ipod_vpd``).
+    No root required; disks stay mounted.
+    """
+    match_dict = _iok.IOServiceMatching(b"com_apple_driver_iPodSBCNub")
+    if not match_dict:
+        return []
+    iterator = c_uint32(0)
+    kr = _iok.IOServiceGetMatchingServices(0, match_dict, byref(iterator))
+    if kr != 0:
+        return []
+
+    results: list[dict] = []
+    try:
+        while True:
+            svc = _iok.IOIteratorNext(iterator.value)
+            if svc == 0:
+                break
+            try:
+                result = _query_one_service(svc, 0, "")
+                if result is not None:
+                    results.append(result)
+            except Exception as exc:
+                log.debug("Failed to query iPod service %d: %s", svc, exc)
+            finally:
+                _iok.IOObjectRelease(svc)
+    finally:
+        _iok.IOObjectRelease(iterator.value)
+
+    return results
+
+
+# ── Internal ─────────────────────────────────────────────────────────
+
+def _query_one_service(
+    service: int, usb_pid: int, serial_filter: str
+) -> dict | None:
+    """Query one iPod IOKit service.  Returns dict or None."""
+    # Get USB info from IOKit registry parents
+    usb_info = _walk_parents_for_usb_info(service)
+
+    # Apply filters
+    if usb_pid and usb_info.get("usb_pid") != usb_pid:
+        return None
+    if serial_filter:
+        svc_serial = usb_info.get("usb_serial", "")
+        if svc_serial.upper() != serial_filter.upper():
+            return None
+
+    with _SCSISession(service) as session:
+        if not session.open():
+            log.debug("Failed to open SCSI session for service %d", service)
+            return None
+
+        info: dict = {
+            "_source": "scsi_vpd",
+            "_transport": "iokit_scsi_vpd",
+        }
+
+        # USB identifiers
+        if "usb_vid" in usb_info:
+            info["usb_vid"] = usb_info["usb_vid"]
+        if "usb_pid" in usb_info:
+            info["usb_pid"] = usb_info["usb_pid"]
+        if "usb_serial" in usb_info:
+            info["usb_serial"] = usb_info["usb_serial"]
+
+        # Standard INQUIRY
+        std = session.inquiry(evpd=False, page=0, alloc_len=96)
+        if std and len(std) >= 36:
+            info["scsi_vendor"] = std[8:16].decode("ascii", errors="replace").strip()
+            info["scsi_product"] = std[16:32].decode("ascii", errors="replace").strip()
+            info["scsi_revision"] = std[32:36].decode("ascii", errors="replace").strip()
+
+        # VPD page 0x80 — Unit Serial Number
+        p80 = session.inquiry(evpd=True, page=0x80)
+        if p80 and len(p80) > 4:
+            sn = p80[4:].split(b"\x00", 1)[0].decode("ascii", errors="replace").strip()
+            if sn:
+                info["vpd_serial"] = sn
+
+        # VPD data pages → XML plist
+        raw_xml = _read_vpd_pages(session)
+        if raw_xml:
+            info["vpd_raw_xml"] = raw_xml
+            plist_data = _parse_vpd_xml(raw_xml)
+            info.update(plist_data)
+
+    return info if info else None

src/vendor/ipod_device/vpd_linux.py

@@ -0,0 +1,266 @@
+"""Linux SG_IO SCSI VPD reader for mounted iPods.
+
+This sends SCSI INQUIRY commands to the block device backing the selected
+mount point.  It avoids PyUSB driver detach/unmount behavior and anchors the
+live SysInfoExtended read to the same mounted iPod the UI selected.
+"""
+
+from __future__ import annotations
+
+import ctypes
+import logging
+import os
+import re
+import sys
+
+from .diagnostic_log import CAPABILITY_FIELDS, IDENTITY_FIELDS, format_fields
+from .sysinfo import normalize_guid, parse_sysinfo_extended
+
+logger = logging.getLogger(__name__)
+
+_SG_IO = 0x2285
+_SG_DXFER_FROM_DEV = -3
+
+
+class _SG_IO_HDR(ctypes.Structure):
+    _fields_ = [
+        ("interface_id", ctypes.c_int),
+        ("dxfer_direction", ctypes.c_int),
+        ("cmd_len", ctypes.c_ubyte),
+        ("mx_sb_len", ctypes.c_ubyte),
+        ("iovec_count", ctypes.c_ushort),
+        ("dxfer_len", ctypes.c_uint),
+        ("dxferp", ctypes.c_void_p),
+        ("cmdp", ctypes.c_void_p),
+        ("sbp", ctypes.c_void_p),
+        ("timeout", ctypes.c_uint),
+        ("flags", ctypes.c_uint),
+        ("pack_id", ctypes.c_int),
+        ("usr_ptr", ctypes.c_void_p),
+        ("status", ctypes.c_ubyte),
+        ("masked_status", ctypes.c_ubyte),
+        ("msg_status", ctypes.c_ubyte),
+        ("sb_len_wr", ctypes.c_ubyte),
+        ("host_status", ctypes.c_ushort),
+        ("driver_status", ctypes.c_ushort),
+        ("resid", ctypes.c_int),
+        ("duration", ctypes.c_uint),
+        ("info", ctypes.c_uint),
+    ]
+
+
+def _whole_disk_candidate(device: str) -> str:
+    real = os.path.realpath(device)
+    base = os.path.basename(real)
+    dirname = os.path.dirname(real)
+    if re.match(r"sd[a-z]+\d+$", base):
+        return os.path.join(dirname, re.sub(r"\d+$", "", base))
+    if re.match(r"(mmcblk|nvme).+p\d+$", base):
+        return os.path.join(dirname, re.sub(r"p\d+$", "", base))
+    return real
+
+
+def _block_candidates(mount_path: str) -> list[str]:
+    try:
+        from .scanner import _linux_find_block_device
+
+        partition = _linux_find_block_device(mount_path)
+    except Exception as exc:
+        logger.debug("Linux SG_IO: mount lookup failed for %s: %s", mount_path, exc)
+        partition = None
+
+    candidates: list[str] = []
+    for path in (partition, _whole_disk_candidate(partition) if partition else None):
+        if path and path not in candidates:
+            candidates.append(path)
+    return candidates
+
+
+def _scsi_inquiry(fd: int, *, evpd: bool, page: int, alloc_len: int = 255) -> bytes:
+    import fcntl
+
+    data_buf = ctypes.create_string_buffer(alloc_len)
+    sense_buf = ctypes.create_string_buffer(64)
+    cdb = (ctypes.c_ubyte * 6)(
+        0x12,
+        0x01 if evpd else 0x00,
+        page & 0xFF,
+        0x00,
+        alloc_len & 0xFF,
+        0x00,
+    )
+
+    hdr = _SG_IO_HDR()
+    hdr.interface_id = ord("S")
+    hdr.dxfer_direction = _SG_DXFER_FROM_DEV
+    hdr.cmd_len = 6
+    hdr.mx_sb_len = len(sense_buf)
+    hdr.dxfer_len = alloc_len
+    hdr.dxferp = ctypes.cast(data_buf, ctypes.c_void_p)
+    hdr.cmdp = ctypes.cast(cdb, ctypes.c_void_p)
+    hdr.sbp = ctypes.cast(sense_buf, ctypes.c_void_p)
+    hdr.timeout = 10000
+
+    fcntl.ioctl(fd, _SG_IO, hdr)
+    if hdr.status != 0 or hdr.host_status != 0 or hdr.driver_status != 0:
+        raise OSError(
+            hdr.status or hdr.host_status or hdr.driver_status,
+            f"SG_IO INQUIRY failed for page 0x{page:02X}",
+        )
+
+    transfer_len = alloc_len - max(int(hdr.resid), 0)
+    if transfer_len <= 0:
+        transfer_len = alloc_len
+    return bytes(data_buf.raw[: min(transfer_len, alloc_len)])
+
+
+def _read_standard_inquiry(fd: int) -> dict:
+    result: dict = {}
+    try:
+        data = _scsi_inquiry(fd, evpd=False, page=0, alloc_len=96)
+    except Exception as exc:
+        logger.debug("Linux SG_IO: standard INQUIRY failed: %s", exc)
+        return result
+
+    if len(data) >= 36:
+        result["scsi_vendor"] = data[8:16].decode("ascii", errors="replace").strip()
+        result["scsi_product"] = data[16:32].decode("ascii", errors="replace").strip()
+        result["scsi_revision"] = data[32:36].decode("ascii", errors="replace").strip()
+    return result
+
+
+def _read_vpd_serial(fd: int) -> str:
+    try:
+        data = _scsi_inquiry(fd, evpd=True, page=0x80, alloc_len=255)
+    except Exception:
+        return ""
+    if len(data) <= 4:
+        return ""
+    return data[4:].split(b"\x00", 1)[0].decode("ascii", errors="replace").strip()
+
+
+def _read_vpd_pages(fd: int) -> bytes:
+    data_pages: list[int] = []
+    try:
+        c0 = _scsi_inquiry(fd, evpd=True, page=0xC0, alloc_len=255)
+        if len(c0) >= 4:
+            count = c0[3]
+            data_pages = [p for p in c0[4:4 + count] if p >= 0xC2]
+    except Exception as exc:
+        logger.debug("Linux SG_IO: VPD page 0xC0 failed: %s", exc)
+
+    if not data_pages:
+        data_pages = list(range(0xC2, 0x100))
+
+    chunks: list[bytes] = []
+    for page in data_pages:
+        try:
+            data = _scsi_inquiry(fd, evpd=True, page=page, alloc_len=255)
+        except Exception:
+            continue
+        if len(data) < 4:
+            continue
+        payload_len = data[3]
+        payload = data[4:4 + payload_len]
+        if payload and any(payload):
+            chunks.append(payload)
+
+    return b"".join(chunks).rstrip(b"\x00")
+
+
+def query_ipod_vpd_for_path(
+    mount_path: str,
+    *,
+    usb_pid: int = 0,
+    serial_filter: str = "",
+) -> dict | None:
+    """Read SCSI VPD SysInfoExtended from a mounted Linux iPod volume."""
+    if sys.platform != "linux":
+        return None
+
+    logger.info(
+        "Linux SG_IO VPD query start: mount=%s pid=%s filter=%s",
+        mount_path,
+        f"0x{usb_pid:04X}" if usb_pid else "unknown",
+        serial_filter or "none",
+    )
+    for device in _block_candidates(mount_path):
+        fd: int | None = None
+        try:
+            fd = os.open(device, os.O_RDONLY | getattr(os, "O_NONBLOCK", 0))
+            result: dict = {
+                "_source": "linux_scsi",
+                "_transport": "linux_sg_io_scsi_vpd",
+                "block_device": device,
+            }
+            if usb_pid:
+                result["usb_pid"] = usb_pid
+                result["usb_vid"] = 0x05AC
+
+            result.update(_read_standard_inquiry(fd))
+            vpd_serial = _read_vpd_serial(fd)
+            if vpd_serial:
+                result["vpd_serial"] = vpd_serial
+
+            raw_xml = _read_vpd_pages(fd)
+            if not raw_xml:
+                logger.info("Linux SG_IO: no SysInfoExtended payload from %s", device)
+                continue
+
+            parsed = parse_sysinfo_extended(raw_xml, source="linux_scsi", live=True)
+            if not parsed.plist:
+                logger.info(
+                    "Linux SG_IO: parsed payload had no plist keys on %s",
+                    device,
+                )
+                continue
+
+            result["vpd_raw_xml"] = parsed.raw_xml or raw_xml
+            result.update(parsed.plist)
+            log_identity = dict(parsed.identity)
+            for field in (
+                "usb_vid",
+                "usb_pid",
+                "scsi_vendor",
+                "scsi_product",
+                "scsi_revision",
+            ):
+                if result.get(field) not in (None, "", b""):
+                    log_identity[field] = result[field]
+
+            wanted = normalize_guid(serial_filter)
+            actual = normalize_guid(
+                result.get("FireWireGUID")
+                or result.get("usb_serial")
+                or result.get("vpd_serial")
+            )
+            if wanted and actual and wanted != actual:
+                logger.info(
+                    "Linux SG_IO: serial filter %s did not match %s on %s",
+                    wanted,
+                    actual,
+                    device,
+                )
+                continue
+
+            logger.info(
+                "Linux SG_IO VPD query successful for %s: keys=%d "
+                "identity=[%s] caps=[%s]",
+                device,
+                len(parsed.plist),
+                format_fields(log_identity, IDENTITY_FIELDS),
+                format_fields(log_identity, CAPABILITY_FIELDS, include_false=True),
+            )
+            return result
+        except PermissionError as exc:
+            logger.info("Linux SG_IO: permission denied opening %s: %s", device, exc)
+        except Exception as exc:
+            logger.info("Linux SG_IO: query failed for %s: %s", device, exc)
+        finally:
+            if fd is not None:
+                try:
+                    os.close(fd)
+                except OSError:
+                    pass
+
+    return None

src/vendor/ipod_device/vpd_usb_control.py

@@ -0,0 +1,211 @@
+"""
+Read iPod SysInfoExtended via Apple's USB vendor-control command.
+
+libgpod uses this path for devices such as later nanos that can expose richer
+SysInfoExtended data over a device-level vendor request than through SCSI VPD.
+It is intentionally separate from ``vpd_libusb``'s Mass Storage Bulk-Only/SCSI
+path so callers can preserve transport provenance.
+"""
+
+from __future__ import annotations
+
+import logging
+
+from .diagnostic_log import CAPABILITY_FIELDS, IDENTITY_FIELDS, format_fields
+from .models import IPOD_USB_PIDS
+from .sysinfo import parse_sysinfo_extended
+from .usb_backend import backend_diagnostic, get_libusb_backend
+
+logger = logging.getLogger(__name__)
+
+APPLE_VID = 0x05AC
+
+_REQUEST_TYPE_IN_VENDOR_DEVICE = 0xC0
+_REQUEST_READ_SYSINFO_EXTENDED = 0x40
+_VALUE_SYSINFO_EXTENDED = 0x0002
+_CHUNK_SIZE = 0x1000
+_MAX_CHUNKS = 0xFFFF
+_TIMEOUT_MS = 5000
+
+
+def _find_ipod_devices() -> list:
+    try:
+        import usb.core
+    except ImportError:
+        logger.info("USB vendor SysInfoExtended: pyusb not installed")
+        return []
+
+    backend = get_libusb_backend()
+    if backend is None:
+        logger.info(
+            "USB vendor SysInfoExtended: no PyUSB backend available: %s",
+            backend_diagnostic(),
+        )
+        return []
+
+    found = usb.core.find(find_all=True, idVendor=APPLE_VID, backend=backend)
+    if found is None:
+        return []
+    return [dev for dev in found if getattr(dev, "idProduct", None) in IPOD_USB_PIDS]
+
+
+def _device_serial(dev) -> str:
+    try:
+        return (dev.serial_number or "").replace(" ", "").strip().upper()
+    except Exception:
+        return ""
+
+
+def _read_sysinfo_extended_from_device(dev) -> bytes:
+    raw = bytearray()
+
+    for index in range(_MAX_CHUNKS):
+        chunk = dev.ctrl_transfer(
+            _REQUEST_TYPE_IN_VENDOR_DEVICE,
+            _REQUEST_READ_SYSINFO_EXTENDED,
+            _VALUE_SYSINFO_EXTENDED,
+            index,
+            _CHUNK_SIZE,
+            timeout=_TIMEOUT_MS,
+        )
+        data = bytes(chunk)
+        raw.extend(data)
+        if len(data) != _CHUNK_SIZE:
+            break
+
+    return bytes(raw).rstrip(b"\x00")
+
+
+def query_ipod_usb_sysinfo_extended(
+    usb_pid: int = 0,
+    serial_filter: str = "",
+) -> dict | None:
+    """Query one iPod through Apple's USB vendor-control SysInfo command.
+
+    Returns a dict shaped similarly to the SCSI VPD readers, with parsed
+    SysInfoExtended keys plus ``vpd_raw_xml``, ``usb_pid``, ``usb_serial`` and
+    provenance metadata.  Returns ``None`` if no matching iPod answers.
+    """
+    # _find_ipod_devices already checks for pyusb availability and the backend.
+    # No need to import usb.core again here.
+
+    serial_filter = serial_filter.replace(" ", "").strip().upper()
+    logger.info(
+        "USB vendor SysInfoExtended query start: pid=%s filter=%s",
+        f"0x{usb_pid:04X}" if usb_pid else "any",
+        serial_filter or "none",
+    )
+    candidates = [
+        dev for dev in _find_ipod_devices()
+        if not usb_pid or getattr(dev, "idProduct", None) == usb_pid
+    ]
+    logger.info(
+        "USB vendor SysInfoExtended candidates: count=%d pids=%s",
+        len(candidates),
+        ", ".join(f"0x{getattr(dev, 'idProduct', 0):04X}" for dev in candidates) or "none",
+    )
+    target = None
+    if serial_filter:
+        for dev in candidates:
+            serial = _device_serial(dev)
+            if serial == serial_filter:
+                target = dev
+                break
+        if target is None and len(candidates) == 1 and usb_pid:
+            # Some Windows libusb driver stacks enumerate the device but refuse
+            # string descriptors.  If PID has already narrowed this to a single
+            # candidate, it is still safe to attempt the read.
+            target = candidates[0]
+    elif candidates:
+        target = candidates[0]
+
+    if target is None:
+        logger.info("USB vendor SysInfoExtended query: no matching target")
+        return None
+
+    usb_serial = _device_serial(target)
+    try:
+        raw_xml = _read_sysinfo_extended_from_device(target)
+    except Exception as exc:
+        message = str(exc)
+        if "not supported" in message.lower() or "not implemented" in message.lower():
+            logger.info(
+                "USB vendor SysInfoExtended backend is available, but Windows "
+                "driver access does not support device control transfers for "
+                "PID=0x%04X serial=%s: %s",
+                getattr(target, "idProduct", 0),
+                usb_serial,
+                exc,
+            )
+        else:
+            logger.info(
+                "USB vendor SysInfoExtended read failed for PID=0x%04X serial=%s: %s",
+                getattr(target, "idProduct", 0),
+                usb_serial,
+                exc,
+            )
+        return None
+
+    if not raw_xml:
+        logger.info(
+            "USB vendor SysInfoExtended query returned empty payload: "
+            "PID=0x%04X serial=%s",
+            getattr(target, "idProduct", 0),
+            usb_serial,
+        )
+        return None
+
+    parsed = parse_sysinfo_extended(raw_xml, source="usb_vendor", live=True)
+    if not parsed.plist:
+        logger.info(
+            "USB vendor SysInfoExtended parse returned no plist keys: "
+            "PID=0x%04X serial=%s",
+            getattr(target, "idProduct", 0),
+            usb_serial,
+        )
+        return None
+
+    result: dict = {
+        "usb_pid": getattr(target, "idProduct", 0),
+        "usb_serial": usb_serial,
+        "vpd_raw_xml": parsed.raw_xml or raw_xml,
+        "_source": "usb_vendor",
+        "_transport": "usb_vendor_control",
+        "_used_usb_vendor": True,
+    }
+    result.update(parsed.plist)
+    log_identity = dict(parsed.identity)
+    log_identity["usb_pid"] = getattr(target, "idProduct", 0)
+    if usb_serial:
+        log_identity["usb_serial"] = usb_serial
+
+    logger.info(
+        "USB vendor SysInfoExtended query successful: PID=0x%04X serial=%s "
+        "keys=%d identity=[%s] caps=[%s]",
+        getattr(target, "idProduct", 0),
+        usb_serial,
+        len(parsed.plist),
+        format_fields(log_identity, IDENTITY_FIELDS),
+        format_fields(log_identity, CAPABILITY_FIELDS, include_false=True),
+    )
+    return result
+
+
+def query_all_ipod_usb_sysinfo_extended() -> list[dict]:
+    """Query every connected iPod that answers the vendor-control command."""
+    results: list[dict] = []
+    for dev in _find_ipod_devices():
+        try:
+            info = query_ipod_usb_sysinfo_extended(
+                usb_pid=getattr(dev, "idProduct", 0),
+                serial_filter=_device_serial(dev),
+            )
+            if info:
+                results.append(info)
+        except Exception as exc:
+            logger.debug(
+                "USB vendor SysInfoExtended query failed for PID=0x%04X: %s",
+                getattr(dev, "idProduct", 0),
+                exc,
+            )
+    return results

src/vendor/ipod_device/vpd_windows.py

@@ -0,0 +1,311 @@
+"""
+Windows SCSI pass-through reader for iPod SysInfoExtended VPD pages.
+
+This sends SCSI INQUIRY commands to the selected drive with
+IOCTL_SCSI_PASS_THROUGH_DIRECT.  It is a live hardware source and avoids
+selecting the wrong iPod by anchoring the query to the mounted drive letter.
+"""
+
+from __future__ import annotations
+
+import ctypes
+import logging
+import os
+import sys
+
+from .diagnostic_log import CAPABILITY_FIELDS, IDENTITY_FIELDS, format_fields
+from .sysinfo import normalize_guid, parse_sysinfo_extended
+
+logger = logging.getLogger(__name__)
+
+# Win32 wintypes are imported inside Windows-only functions to satisfy
+# static analysis and keep runtime imports platform-local.
+
+
+_GENERIC_READ = 0x80000000
+_GENERIC_WRITE = 0x40000000
+_FILE_SHARE_READ = 0x00000001
+_FILE_SHARE_WRITE = 0x00000002
+_OPEN_EXISTING = 3
+
+_IOCTL_SCSI_PASS_THROUGH_DIRECT = 0x0004D014
+_SCSI_IOCTL_DATA_IN = 1
+
+
+class _SCSI_PASS_THROUGH_DIRECT(ctypes.Structure):
+    _fields_ = [
+        ("Length", ctypes.c_ushort),
+        ("ScsiStatus", ctypes.c_ubyte),
+        ("PathId", ctypes.c_ubyte),
+        ("TargetId", ctypes.c_ubyte),
+        ("Lun", ctypes.c_ubyte),
+        ("CdbLength", ctypes.c_ubyte),
+        ("SenseInfoLength", ctypes.c_ubyte),
+        ("DataIn", ctypes.c_ubyte),
+        ("DataTransferLength", ctypes.c_ulong),
+        ("TimeOutValue", ctypes.c_ulong),
+        ("DataBuffer", ctypes.c_void_p),
+        ("SenseInfoOffset", ctypes.c_ulong),
+        ("Cdb", ctypes.c_ubyte * 16),
+    ]
+
+
+def _setup_win32_prototypes() -> None:
+    if sys.platform != "win32":
+        return
+    from ctypes import wintypes as wt
+    ctypes.windll.kernel32.CreateFileW.argtypes = [  # type: ignore[attr-defined]
+        wt.LPCWSTR,
+        wt.DWORD,
+        wt.DWORD,
+        wt.LPVOID,
+        wt.DWORD,
+        wt.DWORD,
+        wt.HANDLE,
+    ]
+    ctypes.windll.kernel32.CreateFileW.restype = wt.HANDLE  # type: ignore[attr-defined]
+    ctypes.windll.kernel32.DeviceIoControl.argtypes = [  # type: ignore[attr-defined]
+        wt.HANDLE,
+        wt.DWORD,
+        wt.LPVOID,
+        wt.DWORD,
+        wt.LPVOID,
+        wt.DWORD,
+        ctypes.POINTER(wt.DWORD),
+        wt.LPVOID,
+    ]
+    ctypes.windll.kernel32.DeviceIoControl.restype = wt.BOOL  # type: ignore[attr-defined]
+    ctypes.windll.kernel32.CloseHandle.argtypes = [wt.HANDLE]  # type: ignore[attr-defined]
+    ctypes.windll.kernel32.CloseHandle.restype = wt.BOOL  # type: ignore[attr-defined]
+
+
+def _drive_letter_from_path(path: str) -> str:
+    if not path:
+        return ""
+    drive, _tail = os.path.splitdrive(path)
+    if drive and drive[0].isalpha():
+        return drive[0].upper()
+    if path[0].isalpha():
+        return path[0].upper()
+    return ""
+
+
+def _open_drive(drive_letter: str):
+    path = f"\\\\.\\{drive_letter}:"
+    handle = ctypes.windll.kernel32.CreateFileW(  # type: ignore[attr-defined]
+        path,
+        _GENERIC_READ | _GENERIC_WRITE,
+        _FILE_SHARE_READ | _FILE_SHARE_WRITE,
+        None,
+        _OPEN_EXISTING,
+        0,
+        None,
+    )
+    invalid = ctypes.c_void_p(-1).value
+    if handle == invalid:
+        err = getattr(ctypes, "get_last_error", lambda: 0)()
+        logger.info("Windows SCSI VPD: cannot open %s (err=%d)", path, err)
+        return None
+    return handle
+
+
+def _scsi_inquiry(handle, *, evpd: bool, page: int, alloc_len: int = 255) -> bytes:
+    from ctypes import wintypes as wt
+    data_buf = ctypes.create_string_buffer(alloc_len)
+    sptd = _SCSI_PASS_THROUGH_DIRECT()
+    sptd.Length = ctypes.sizeof(_SCSI_PASS_THROUGH_DIRECT)
+    sptd.CdbLength = 6
+    sptd.DataIn = _SCSI_IOCTL_DATA_IN
+    sptd.DataTransferLength = alloc_len
+    sptd.TimeOutValue = 10
+    sptd.DataBuffer = ctypes.cast(data_buf, ctypes.c_void_p)
+    sptd.SenseInfoLength = 0
+    sptd.SenseInfoOffset = 0
+
+    cdb = bytes([
+        0x12,
+        0x01 if evpd else 0x00,
+        page & 0xFF,
+        0x00,
+        alloc_len & 0xFF,
+        0x00,
+    ])
+    for idx, byte in enumerate(cdb):
+        sptd.Cdb[idx] = byte
+
+    returned = wt.DWORD(0)
+    ok = ctypes.windll.kernel32.DeviceIoControl(  # type: ignore[attr-defined]
+        handle,
+        _IOCTL_SCSI_PASS_THROUGH_DIRECT,
+        ctypes.byref(sptd),
+        ctypes.sizeof(sptd),
+        ctypes.byref(sptd),
+        ctypes.sizeof(sptd),
+        ctypes.byref(returned),
+        None,
+    )
+    if not ok:
+        err = getattr(ctypes, "get_last_error", lambda: 0)()
+        raise OSError(err, f"DeviceIoControl INQUIRY failed for page 0x{page:02X}")
+    if sptd.ScsiStatus != 0:
+        raise OSError(sptd.ScsiStatus, f"SCSI status for page 0x{page:02X}")
+
+    transfer_len = min(int(sptd.DataTransferLength or alloc_len), alloc_len)
+    return bytes(data_buf.raw[:transfer_len])
+
+
+def _read_standard_inquiry(handle) -> dict:
+    result: dict = {}
+    try:
+        data = _scsi_inquiry(handle, evpd=False, page=0, alloc_len=96)
+    except Exception as exc:
+        logger.debug("Windows SCSI VPD: standard INQUIRY failed: %s", exc)
+        return result
+
+    if len(data) >= 36:
+        result["scsi_vendor"] = data[8:16].decode("ascii", errors="replace").strip()
+        result["scsi_product"] = data[16:32].decode("ascii", errors="replace").strip()
+        result["scsi_revision"] = data[32:36].decode("ascii", errors="replace").strip()
+    return result
+
+
+def _read_vpd_serial(handle) -> str:
+    try:
+        data = _scsi_inquiry(handle, evpd=True, page=0x80, alloc_len=255)
+    except Exception:
+        return ""
+    if len(data) <= 4:
+        return ""
+    return data[4:].split(b"\x00", 1)[0].decode("ascii", errors="replace").strip()
+
+
+def _read_vpd_pages(handle) -> bytes:
+    data_pages: list[int] = []
+    try:
+        c0 = _scsi_inquiry(handle, evpd=True, page=0xC0, alloc_len=255)
+        if len(c0) >= 4:
+            count = c0[3]
+            data_pages = [p for p in c0[4:4 + count] if p >= 0xC2]
+            logger.debug(
+                "Windows SCSI VPD pages: %s",
+                [f"0x{page:02X}" for page in data_pages],
+            )
+    except Exception as exc:
+        logger.debug("Windows SCSI VPD: page 0xC0 failed: %s", exc)
+
+    if not data_pages:
+        data_pages = list(range(0xC2, 0x100))
+
+    chunks: list[bytes] = []
+    for page in data_pages:
+        try:
+            data = _scsi_inquiry(handle, evpd=True, page=page, alloc_len=255)
+        except Exception:
+            continue
+        if len(data) < 4:
+            continue
+        payload_len = data[3]
+        payload = data[4:4 + payload_len]
+        if payload and any(payload):
+            chunks.append(payload)
+
+    return b"".join(chunks).rstrip(b"\x00")
+
+
+def query_ipod_vpd_for_path(
+    mount_path: str,
+    *,
+    usb_pid: int = 0,
+    serial_filter: str = "",
+) -> dict | None:
+    """Read SCSI VPD SysInfoExtended from the selected Windows drive."""
+    if sys.platform != "win32":
+        return None
+
+    drive_letter = _drive_letter_from_path(mount_path)
+    if not drive_letter:
+        logger.debug(
+            "Windows SCSI VPD: no drive letter for mount path %s",
+            mount_path,
+        )
+        return None
+
+    logger.debug(
+        "Windows SCSI VPD query start: drive=%s mount=%s pid=%s filter=%s",
+        drive_letter,
+        mount_path,
+        f"0x{usb_pid:04X}" if usb_pid else "unknown",
+        serial_filter or "none",
+    )
+    _setup_win32_prototypes()
+    handle = _open_drive(drive_letter)
+    if handle is None:
+        return None
+
+    try:
+        result: dict = {
+            "_source": "windows_scsi",
+            "_transport": "windows_scsi_pass_through",
+        }
+        if usb_pid:
+            result["usb_vid"] = 0x05AC
+            result["usb_pid"] = usb_pid
+
+        result.update(_read_standard_inquiry(handle))
+        vpd_serial = _read_vpd_serial(handle)
+        if vpd_serial:
+            result["vpd_serial"] = vpd_serial
+
+        raw_xml = _read_vpd_pages(handle)
+        if not raw_xml:
+            logger.debug(
+                "Windows SCSI VPD: no SysInfoExtended payload for %s",
+                drive_letter,
+            )
+            return None
+
+        parsed = parse_sysinfo_extended(raw_xml, source="windows_scsi", live=True)
+        if not parsed.plist:
+            logger.debug(
+                "Windows SCSI VPD: parsed payload had no plist keys for %s",
+                drive_letter,
+            )
+            return None
+
+        result["vpd_raw_xml"] = parsed.raw_xml or raw_xml
+        result.update(parsed.plist)
+        log_identity = dict(parsed.identity)
+        for field in (
+            "usb_vid",
+            "usb_pid",
+            "scsi_vendor",
+            "scsi_product",
+            "scsi_revision",
+        ):
+            if result.get(field) not in (None, "", b""):
+                log_identity[field] = result[field]
+
+        wanted = normalize_guid(serial_filter)
+        actual = normalize_guid(
+            result.get("FireWireGUID")
+            or result.get("usb_serial")
+            or result.get("vpd_serial")
+        )
+        if wanted and actual and wanted != actual:
+            logger.debug(
+                "Windows SCSI VPD: serial filter %s did not match %s",
+                wanted,
+                actual,
+            )
+            return None
+
+        logger.debug(
+            "Windows SCSI VPD query successful for %s: keys=%d identity=[%s] caps=[%s]",
+            drive_letter,
+            len(parsed.plist),
+            format_fields(log_identity, IDENTITY_FIELDS),
+            format_fields(log_identity, CAPABILITY_FIELDS, include_false=True),
+        )
+        return result
+    finally:
+        ctypes.windll.kernel32.CloseHandle(handle)  # type: ignore[attr-defined]

tests/test_basic.py

@@ -1,57 +0,0 @@
-#!/usr/bin/env python3
-"""
-Basic tests for neo-pod-desktop
-"""
-
-import os
-import sys
-import unittest
-from unittest.mock import patch, MagicMock
-
-sys.path.insert(0, os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "src"))
-
-from audio_converter import AudioConverter
-from metadata_handler import MetadataHandler
-
-
-class TestAudioConverter(unittest.TestCase):
-    """Test audio converter functionality"""
-
-    def test_sanitize_filename(self):
-        """Test filename sanitization"""
-        converter = AudioConverter()
-
-        sanitized = converter._sanitize_filename('File: with "invalid" chars?')
-        self.assertEqual(sanitized, 'File_ with _invalid_ chars_')
-
-        long_name = "A" * 150
-        sanitized = converter._sanitize_filename(long_name)
-        self.assertEqual(len(sanitized), 100)
-        self.assertTrue(sanitized.endswith('...'))
-
-
-class TestMetadataHandler(unittest.TestCase):
-    """Test metadata handler functionality"""
-
-    @patch('requests.get')
-    def test_download_thumbnail(self, mock_get):
-        """Test thumbnail download"""
-        mock_response = MagicMock()
-        mock_response.raise_for_status.return_value = None
-        mock_response.content = b'fake_image_data'
-        mock_get.return_value = mock_response
-
-        with patch('PIL.Image.open') as mock_image_open:
-            mock_image = MagicMock()
-            mock_image.save.return_value = None
-            mock_image_open.return_value = mock_image
-
-            handler = MetadataHandler()
-            result = handler.download_thumbnail("https://example.com/image.jpg")
-
-            self.assertIsNotNone(result)
-            mock_get.assert_called_once_with("https://example.com/image.jpg", timeout=10)
-
-
-if __name__ == "__main__":
-    unittest.main()