Paloma is a program to manage an SQL database of digital music files, and facilitate their retrieval and playback in interesting ways. It works with music files of any form -- MP3, Ogg Vorbis, MIDI... whatever you've got a player for. Paloma makes it easy to rip your entire CD collection and store it on your hard disk (or a collection of CD-Rs) for instant random access; playlists can then be generated using arbitrary SQL commands.
KFreeDB is an application for interacting with the FreeDB disc information database. It allows the user to query the database for a disc in a local drive, or submit new entries. It communicates with the FreeDB server via HTTP. It also features support for inexact/multiple matches, and resubmission of entries.
python-musicbrainz2 provides simple, object oriented access to the MusicBrainz Web service. The MusicBrainz Project (see http://musicbrainz.org) provides music metadata maintained by its large and constantly growing user community. This package helps you to write CD ripper applications, taggers, and media players by giving easy access to music metadata.