libxmp is a module player library which supports many mainstream and obscure module formats, including Protracker MOD, Scream Tracker III S3M, and Impulse Tracker IT. Possible applications for libxmp include standalone module players, module player plugins for other players, module information extractors, background music replayers for games and other applications, module-to-mp3 converters, etc.
The Advanced Linux Sound Architecture is composed of several parts. The first is a fully modularized sound driver which supports module autoloading, devfs, isapnp autoconfiguration, and gives complete access to analog audio, digital audio, control, mixer, synthesizer, DSP, MIDI, and timer components of audio hardware. It also includes a fully-featured kernel-level sequencer, a full compatibility layer for OSS/Free applications, an object-oriented C library which covers and enhances the ALSA kernel driver functionality for applications (client/server, plugins, PCM sharing/multiplexing, PCM metering, etc.), an interactive configuration program for the driver, and some simple utilities for basic management.
mod_musicindex is an Apache module aimed at being a C alternative to the Perl module Apache::MP3. It allows nice displaying of directories containing MP3, Ogg Vorbis, FLAC, or MP4/AAC files, including sorting them on various fields, streaming/downloading them, constructing playlists, and searching. It also provides features such as RSS and Podcast feeds, multiple CSS support, and archive downloads.
Beast is a powerful music composition and modular synthesis application. It offers multiple input methods like multitrack, piano roll, and pattern editing and supports skins. On the technical side, it has a wide range of abilities like sequencing, unlimited undo/redo history, real-time synthesis with multiprocessor support, full duplex 32-bit audio rendering, precise timing down to sample granularity, on demand loading of partial wave files, on the fly decoding of various sample formats, aliasing free oscillators, and full Scheme scripting support.
FluidSynth is a real-time software synthesizer based on the SoundFont 2 specifications. It can read MIDI events from MIDI input devices or files and render them to an audio device using SoundFont instrument banks. It can also play MIDI files. Other features include real time effect control and a powerful API for embedding FluidSynth in other programs.
LAME (LAME Ain't an MP3 Encoder) is a research project for learning about and improving MP3 encoding technology. LAME includes an MP3 encoding library, a simple frontend application, and other tools for sound analysis, as well as convenience tools. Please note that any commercial use (including distributing the LAME encoding engine in a free encoder) may require a patent license from Thomson Multimedia.