CD Ripper > MusicBrainz TOC

This is for those of you who are interested in the technical details.

Each CD has a "table of contents" (TOC), which is used to calculate the MusicBrainz Disc ID, and the original 32-bit FreeDB disc id. The TOC is an index into the contents of the CD, which indicates the start "sector" of the track on the CD, and number of sectors is uses. Where a "sector" is a chunk of data that is 2352 bytes long, and... Ok, that's enough technical stuff - ed.

Usually each CD, sometimes even different releases of the same CD, will have slight differences in the TOC and so will be assigned different Disc IDs. Here's an example of a rather boring CD with four different releases in different countries, which all have the same TOC, the same Disc ID and the same barcode.