Mad is an mpeg audio decoder. it currently only supports the mpeg 1 standard, but fully implements all three audio layers (layer i, layer ii, and layer iii, the latter often colloquially known as mp3.)

mad has the following special features:
- 100% fixed-point (integer) computation
- completely new implementation based on the iso/iec 11172-3 standard
- distributed under the terms of the gnu general public license (gpl)