It is in the format the disc is written, and the data that tells the player is in the TOC (Table Of Contents) on the disc. Data CD's use a different file format & system to Audio CD's.
I believe you're looking for the CD-DA redbook and yellowbook specifications. As far as I know, these are proprietary specs written by Philips (and Sony?). -Rusty http://www.mediamonkey.com We're bananas about music