dudl is a collection of tools to grab, encode, and rename MP3 files, archive them, and maintain a database of all files. On top of this runs the dudld Jukebox daemon that plays your files through gstreamer. dudld's strengths are the powerful tag based filters, the capability to cope with very large collections, and the network protocol to control its operation. There is a full featured command-line client, a minimalistic GTK client, and a lirc client. Writing new clients should be easy with the supplied client libraries.
OpenDJMix is a virtual DJ system which allows you to mix MP3 files and audio CD tracks. It consists of a C++ API that manages a virtual sound bus with its I/O and a Qt GUI that enables a user to mix 4 MP3 or audio CD tracks. The API has been designed to be used in all multitrack sound tools.
SvOlli's Little Audio Related Thingies, or SLART for short, is a compilation of rather simple programs that are related to audio files: it consists of a player (Partyman), a CD ripper, a tag editor, and some other tools. These programs can communicate with each other via a custom IPC bus, so a newly ripped track can be automatically queued in the player, for example.
ioAmarok is a music player for Infodomestic Objects (Linux/BSD) with an intuitive interface. It is built with SpatialBundle technology, so it does not require installation nor any administrator privilege access. It does not depend on any libraries such as the KDE libraries nor the Qt libraries.
FUPlayer is a full featured music manager and player for the GNOME desktop. With it, you can play music from your hard drive, create playlists, do real file management using its Trash, and play, rip, and burn audio CDs. It features an interface similar to those of many modern manager-style players, but with many improvements, such as true non-modal search and browse functionality, find-as-you-type, and drag destination highlighting. It aims to be extremely user friendly and efficient to use.
A.M.I.C.U.S. (Automatic Multimedia Installation Configuration Utility System) helps users quickly and easily install and configure MythTV on generic PC hardware. It uses the Debian Netinst CD to install GNU/Linux and just the required packages to allow a functional MythTV on low end hardware.