MusicBrainz is a project that aims to create an open data music database that is similar to the freedb project.

Qmmp is a free and open-source audio player written in C++ with the help of the Qt library.

EasyTag (EasyTAG) is a graphical tag editor for Linux and Microsoft Windows.

freedb is a database of compact disc track listings, where all the content is under the GNU General Public License.