Format Spec: Audio Archives (Music.dat / Sfx.dat / Voice.dat)

Status: Header structure decoded — codec and index layout unresolved
Source disc: Scooby-Doo! Showdown in Ghost Town (2000, The Learning Company)
Sample files: scooby\Music.dat (91.7 MB), scooby\Sfx.dat (30.7 MB), scooby\Voice.dat (103.8 MB) on the Showdown disc

Vision doc reference: Project Vision — Phase 1 work item

For Phase 1, codec identification is sufficient. Full decode integration can defer to Phase 3 if ScummVM already supports the identified codec.

Findings

Shared header structure

All three files open with the same three-field 12-byte header:

Offset  Size  Type      Notes
------  ----  --------  -----
0x00       4  uint32LE  Version — always 1
0x04       4  uint32LE  Entry count (see table below)
0x08       4  uint32LE  Total data size in bytes (≈ file size; exact match TBD)

Confirmed values:

The data-size field is within ~20 KB of the actual file size — likely the payload region size, not counting the header + index.

Entry counts are plausible:

• 28 music tracks — typical for a full adventure game soundtrack.
• 316 sound effects — large but credible (footsteps, item sounds, ambient loops, UI).
• 821 voice clips — Scooby-Doo has extensive spoken dialogue; this matches.

Index table layout

The 12-byte header is followed by zero-padded bytes through at least offset 79 (confirmed via hex inspection). The index table location is not yet resolved — candidate positions:

1. Immediately after the header at offset 12, but with an entry size larger than 8 or 12 bytes (all-zero observations may reflect name/string fields before offset data).
2. Appended at the end of the file, before or after the audio payloads.
3. At a fixed offset specified by a field we haven’t yet decoded (e.g., field at 0x08 could be an offset rather than a size).

Codec

No standard magic bytes at file offset 0 (RIFF, OggS, ID3, fLaC). Codec is unknown until an individual audio entry is located and inspected. Likely candidates for a year-2000 Windows edutainment title:

• IMA ADPCM (common in mid-2000s game audio)
• Miles Sound System (MSS header) — widely licensed in that era
• Uncompressed PCM (WAV-like)

Remaining unknowns

• Location of the index table (offset 12 or elsewhere).
• Entry record size and field layout (offset, size, sample rate, channels, codec flag?).
• Codec identity — needs at least one clip extracted and inspected.
• Whether clips are referenced by numeric index or by string name (affects how Scooby.exe resolves a logical sound to an archive entry).
• Whether all three files share an identical index format.

Next steps

1. Write tools/probe_audio.py — scan each .dat for codec magic bytes (RIFF, OggS, MSS, etc.) at fixed alignment intervals to locate individual clips and infer entry stride.
2. Once a clip boundary is found, work backwards to reconstruct the index record format.
3. Cross-reference against object.ini sound references (e.g. pickupsfx) to understand the logical ID → archive entry lookup.
4. Map identified codec to ScummVM’s audio/ subsystem — identify any decoder work needed.

Success condition

Each of Music.dat, Sfx.dat, Voice.dat has its codec named in writing. At least one clip from one of the three is extracted and plays in an external player (ffmpeg / VLC).

References

• Vision doc: Project Vision — Phase 1, audio archives
• ScummVM audio subsystem: audio/ in the ScummVM tree
• Companion specs: tgifile-art, scooby-exe