freedb is a database of compact disc track listings, where all the content is under the GNU General Public License. It was originally based on the now-proprietary CDDB (compact disc database). As of April 24, 2006, the database holds just under 2,000,000 CDs. To look up CD information over the Internet, a client program calculates a hash function from the CD table of contents and uses it as a disc ID to query the database. If the disc is in the database, the client is able to retrieve and display the artist, album title, tracklist and some additional information.
On July 1, 2006, two of the main freedb developers resigned. Although this caused worry over the future of the project, it was announced on July 7, 2006 that plans were in place that would most likely find freedb a new home and it would continue its operation as normal.
On October 4, 2006, freedb owner Michael Kaiser announced that Magix had acquired freedb. On June 25, 2007, MusicBrainz — a project with similar goals — officially released their freedb gateway. The latter allows users to harvest information from the MusicBrainz database rather than freedb.
The original software behind CDDB was released under the GNU General Public License, and many people submitted CD information thinking the service would also remain free. The license was later changed, however, and some programmers complained that the new license included certain terms that they couldn't accept: if one wanted to access CDDB, one was not allowed to access any other CDDB-like database (such as freedb), and any programs using a CDDB lookup had to display a CDDB logo while performing the lookup.
In March 2001, CDDB, now owned by Gracenote, banned all unlicensed applications from accessing their database. New licenses for CDDB1 (the original version of CDDB) were no longer available, since Gracenote wanted to force programmers to switch to CDDB2 (a new version incompatible with CDDB1 and hence with freedb). The license change motivated the freedb project, which is intended to remain free.
Classical music 
Because it inherited the CDDB limitations, there is no data field in the freedb database for composer. This limits its usefulness for classical music CDs. Furthermore, CDs in a series are often introduced in the database by different people, resulting in inconsistent spelling and naming conventions across discs.
Client software (freedb aware applications) 
See also 
- "Massive duplicate cleanup completed". freedb. Retrieved 2006-05-09.[dead link]
- ""The future of freedb" from the [[Wayback Machine]]". Retrieved 2006-07-02. Wikilink embedded in URL title (help)
- "Updates in recent developments with freedb". Retrieved 2006-07-08.[dead link]
- "MAGIX acquires freedb". Retrieved 2006-10-05.
- Kaye, Robert (2007-06-25). "FreeDB → MusicBrainz gateway now available!". MusicBrainz. Retrieved 2007-07-10.
- "Why freedb.org?". freedb. Retrieved 2006-05-09.
- Tips on using CD Trustee - Classical music
- Taming iTunes for Classical Music