mpd

About mpd

From Debian's package description

Music Player Daemon (MPD) is a server that allows remote access for playing audio files (Ogg-Vorbis, FLAC, MP3, Wave, and AIFF), streams (Ogg-Vorbis, MP3) and managing playlists. Gapless playback, buffered output, and crossfading support is also included. The design focus is on integrating a computer into a stereo system that provides control for music playback over a TCP/IP network. The goals are to be easy to install and use, to have minimal resource requirements (it has been reported to run fine on a Pentium 75), and to remain stable and flexible.

The daemon is controlled through a client which need not run on the same computer mpd runs on. The separate client and server design allows users to choose a user interface that best suites their tastes independently of the underlying daemon (this package) which actually plays music.

From Debian's description of the mpd package, under that package's license.