libmad0 binary package in Ubuntu Bionic i386

 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)

Source package