mpg321 is a free replacement for mpg123, a very popular command-line mp3 player. mpg123 is used for frontends, as an mp3 player and as an mp3 to wave file decoder (primarily for use with CD-recording software.) In all of these capacities, mpg321 can be used as a drop-in replacement for mpg123.
mpg321 is a project conceived and written by Joe Drew . It uses code from the MAD distribution by Rob Leslie; XMMS; and plaympeg from the SMPEG distribution. mpg321 is licensed under the GNU General Public License version 2, as documented in the 'COPYING' file.