MPEG4IP: open source MPEG4 package
MPEG-4 AAC audio encoder, MP3 encoder, MPEG-4 video encoders, MP4 file creator and hinter, IETF standards-based streaming server, MPEG-4 player. Mostly Linux-based.

Oidua
A flexible program for generating lists of music collections.

Open Sound World
Open-source programming environment that allows musicians sound processing in response to real-time control.

orDrumbox
Real-time drum machine and audio sequencer (Java) [OS Independent].

StreamStudio
Open source based platform for Internet streaming of audio-visual media.

MP3 Book Helper
Provides Mp3 and Ogg Vorbis tags editing and file renaming functions. (Delphi) [Windows]