M4A files store the iTunSMPB value behind a 16-byte binary 'data' atom
header. The previous parser took bytes directly after the ASCII key,
landing in the binary header and producing a corrupted parts array
(total_valid=348 instead of ~13M samples), which caused take_duration
to exhaust the source in ~8ms — silent no-playback.
Fix: search for the " 00000000 " sentinel within 128 bytes of the key
to locate the actual value string, falling back to the old offset for
ID3v2/MP3 files where no binary header exists.
Also patches symphonia-format-isomp4 (local crate under patches/) to:
- Tolerate SL descriptor predefined=0x01 (older iTunes M4A)
- Convert descriptor.unwrap() panic to a proper decode error
- Gracefully skip malformed trak atoms (e.g. MJPEG cover-art streams)
instead of failing the entire probe
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Psychotoxical