How to salvage a gigantic, possibly corrupt, AIFF file?

Question

Due to a Sound Track Pro glitch, I have a problematic AIF file. It plays fine in QuickTime Player, and is about 1 hour 50 mins long. However:

• It's 3.81GB in size, whereas (I believe) AIF files are only supposed to be 2GB or smaller.
• iTunes refuses to play it.
• Logic Pro gives the error message "party-mix.aif is empty!" when I try to import it.
• VLC will open and play the file, but it ends after an 1 hour (I guess this is the 2GB point).

• Attempting to transcode using ffmpeg to Ogg gives the errors,

  [aiff @ 0x102051000] max_analyze_duration 5000000 reached at 5001333

  ....

  [pcm_s16be @ 0x10205a200] invalid PCM packet

  but the resulting file plays in VLC up till 1 hour, when it ends.

• Attempting to transcode using ffmpeg to MP3 gives similar results as Ogg, except that the number of channels must reduced from 6 to 2. This is odd because it was a stereo project - where the extra 4 channels came from I have no idea.
• There are a few places where the audio has been very noticeably sped up.

My question: how can I transcode this frankenstein monster to MP3 without losing the second half? I am running Mac OS 10.6.8.

Answer 1

Break the source file into two target files

This may not be as painful as it sounds. AIFF is a really simple format, it should be easy to parse with custom code or even some *nix cli tools on mathematically determined boundaries.

• Correct parse of file: Write a simple AIFF parser that can read the frames ("chunk" in AIFF world, I understand) a AIFF file larger than 2GB. Decide on a frame to cut at, and create two files.
• Hacky cut-n-tweek: As long as you cut the file exactly on a frame boundary, you should be able to get the 2nd half clip to play. Maybe you'll have to pre-pad some header data.

Tools that would be useful in exploring the AIFF format:

• hexdump (along with tail and head)
• cut