GramoFile is intended primarily for transferring gramophone records to CDs, but has many other possible uses. It can record very long .wav files with a bargraph signal peak-level meter, playback any part of the files, split long .wav files into separate tracks (with automatic track location), and process the signal with filters to reduce ticks and pops (multiple filters are provided, they can be applied in any order (multiple instances) with user-adjustable parameters). Track splitting and signal processing are done in the same run, and don't need any temporary files.
KeyKit is a multi-tasking interpreted programming language (inspired by awk) designed exclusively for realtime and algorithmic MIDI manipulation. KeyKit's GUI provides several dozen tools for algorithmic music experimentation, including a multi-track sequencer and drum pattern editor. The GUI and all tools are completely written in the KeyKit language itself. This allows users to add new tools and operations to the existing tools, even while the system is running. Complete C source code and precompiled executables for Windows and Linux are provided.
Mup produces very high quality PostScript printed music or a MIDI file from a text input file. It can handle almost any kind of music, instrumental or vocal, including tablature, shaped notes, guitar grids, alternate tunings, user-defined symbols, and much more. Mup has been under active development since 1992.
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.