Mikmod is a module player and library supporting many formats, including mod, s3m, it, and xm. Originally a player for MS-DOS, MikMod has been ported to other platforms, such as Unix, Macintosh, BeOS, and Java(!!)
A multi-format module player and library
xmp is a module player for Unix-like systems that plays over 90 mainstream and obscure module formats from Amiga, Atari, Acorn, Apple IIgs and PC, including Protracker (MOD), Scream Tracker 3 (S3M), Fast Tracker II (XM) and Impulse Tracker (IT) files.
libTiMidity is a MIDI to WAVE converter library that uses Gravis Ultrasound-compatible patch files to generate digital audio data from General MIDI files. This library based on the TiMidity decoder from SDL_sound library.