This was recently added as README.mp3: * Asterisk MP3 Support ===================== Asterisk supports mp3 playback for music on hold via the mpg123 program, available from www.mpg123.de. The latest release of mpg123 is mpg123 0.59r. The latest development release of mpg123 is mpg123 pre0.59s. Please use mpg123 0.59r. Using mpg123 pre0.59s can/may/will result in crashes and/or unreliable playback.
> This was recently added as README.mp3:Yes, and there was recently added a $ make mpg123 target to Asterisk's Makefile. It will use "wget" to download mpg123 0.59r, extract it and compile it. When you later $ make install then it this working mpg123 will be installed into /usr/local/bin