Note: MetaMusicDB has been superseded by a new project, Música, and is therefore discontinued. Bugs will not be fixed.

MetaMusicDB is a free software project written in C++/Qt. It is a frontend to a SQL database for meta information about audio files. The current development status can be described as "working with some features missing" (and probably many bugs).

MetaMusicDB is released as open source under the GPLv3. You can get the code from sourceforge

Features:

• Support of many audio formats (built on TagLib)
• The audio files are kept unchanged, all information is stored in a SQLite database
• Portable: Multi-platform (Qt supports Linux, Windows and Mac); the database is portable between systems, since MetaMusicDB tries hard not to loose any information by tracking filename or tag changes (if you change both you can fix issues by hand)
• Support of an arbitrary number of custom comments and rating tags.
• Searching
• Simple export of search results to media players.

What MetaMusicDB is not:

• A tagging tool. Use easytag, it is great.
• A media player. We can append files to a playlist of a running player, this should be enough.