MusicBrainz

...is a user-maintained community music metadatabase

MusicBrainz provides a catalog of music metadata such as the artist name, the release title, and the list of tracks that appear on a release. Since 2005, users have the option to further relate each of these entities using a detailed set of relationships (i.e. who played which instrument on a release/track). MusicBrainz only provides the data about the music (i.e. metadata) and not the music itself. MusicBrainz does not condone copyright infringement and thus cannot help you find the best place to illegally download copyrighted works. Learn more about MusicBrainz...

...provides solutions to identify and label digital music files

MusicBrainz has many software applications for identifying and labelling digital music files with data from the MusicBrainz database. The currently supported application, the Picard Tagger, uses "PUIDs" to semi-automatically identify tracks in your music collection using audio fingerprints, and then write consistent and accurate metadata to your music files.