This archive contains three things:

1) a WAV<->ADPCM codec written in C, both source and executable included
2) an ADPCM decoder optimized for 68000
3) an ADPCM replayer for Amiga, including a Paula audio driver

The C codec is reference code from Stichting Mathematisch Centrum (see source code for copyright).
The 680x0 specific code has been written by Mikael Kalms (mikael@kalms.org).
