mp3tools is a set of utilities (mp3id3, mp3info, mp3index, and mp3gui) for managing collections of MPEG audio files. It can get information such as bitrate and play length about a file, view and alter ID3 tags, and generate completely customized listings. All of these functions can be done either from the command line or a GUI.
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.
php-stream is a front end for the stream-db icecast/shoutcast MP3 file streamer. php-stream uses the same database backend for queues and logs as stream-db. Users will be able to make their own playlists of songs, and the system playlists will be the complete set of songs that make up an individual album. Full access control will be provided, to set limits on the number of songs and playlists a user can submit to the system. The aim the project is to allow people to create their own streaming media stations, with users, requests, song histories, and playlists.
PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
Sfront compiles MPEG 4 Structured Audio (MP4-SA) programs into efficient C programs that generate audio when executed. MP4-SA is a standard for normative algorithmic sound, which combines an audio signal processing language (SAOL) with score languages (MIDI and SASL). Under Mac OS X and Linux, sfront supports real-time, low-latency audio input/output and MIDI input. Under Mac OS X, sfront supports the creation of AudioUnit plug-ins. The documentation includes a book about SAOL programming.