CDDB

From Free net encyclopedia

CDDB (which stands for Compact Disc Database) is a database for software applications to look up audio CD (compact disc) information over the Internet. This is performed by a client which calculates a (nearly) unique disc ID and then queries the database. As a result, the client is able to display the artist name, CD title, track list and some additional information.

The database is used primarily by media player and CD ripper software.

The need for CDDB is a direct consequence of the original design of the CD, which was conceived as an evolution of the gramophone record, and did not consider the audio tracks as data files to be identified and indexed. The audio CD format does not include the disc name or track names, therefore a supplemental database is needed to supply this information when discs are used with modern media systems. A later development called CD-TEXT is another solution to the same problem.

1 History
2 How A CDDB Works
3 Alternatives
4 External links

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History

CDDB was invented by Ti Kan and Steve Scherf. The source code was released under the GNU General Public License, and thus many people submitted CD information believing that the contributions, too, would remain freely available to others. Later, however, the project was sold and the license conditions were changed and it was no longer a free service, requiring commercial developers to pay an "initial fee", as well as a license fee based on the usage of the servers and support. It also included terms that many programmers felt were unacceptable: no other similar database (such as freedb) could be accessed in addition to CDDB, and the CDDB logo was required to be displayed while the database was being accessed.

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 not available anymore, as they wanted to force programmers to switch to CDDB2 (a new version incompatible with CDDB1 and hence with freedb).

After the unpopular commercialization of CDDB as Gracenote, most media player applications switched to freedb, but continued to refer to the service as 'CDDB' as a generic term. It is still common to see many applications refer to CDDB in their documentation when in fact the application is using freedb.

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How A 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. 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.

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 different CDs that have the same number of tracks and the same track lengths.

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Alternatives

The license change motivated a new project, freedb, which is intended to remain free.

An alternative project that aims to enhance CDDB beyond a mere database of CDs is called MusicBrainz. Their site also contains more information on CDDB and some database statistics of CDDB and freedb.

Another commercial alternative to CDDB is the AMG LASSO service. LASSO was launched by All Media Guide in late 2004 and includes recognition technology for CDs, DVDs, and digital audio files. Microsoft's Windows Media Player, Musicmatch Jukebox, and the Virgin Digital Megastore are licensees.

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