CDDB - How CDDB Works

How CDDB Works

CDDB was designed around the task of identifying entire CDs, not merely single tracks. The identification process involves creating a "discid", a sort of "fingerprint" of a CD created by performing calculations on the track duration information stored in the table-of-contents of the CD (see the following section for an example calculation). This discid is used with the Internet database, typically either to download track names for the whole CD or to submit track names for a newly-identified CD.

This information is often provided by end users. In iTunes, which uses Gracenote, users name the CD tracks and then use the "Submit Track Names" option under the "Advanced" heading in the toolbar to submit track information.

Since identification of CDs is based on the length and order of the tracks, CDDB cannot identify playlists in which the order of tracks has been changed, or compilations of tracks from different CDs. CDDB also cannot distinguish between different CDs that have the same number of tracks and the same track lengths.