mpgtx was designed with the good old Unix philosophy in mind : do few but
do it well and provide end user an austary yet powerfull command line
interface.

   - mpgtx can currently split and join MPEG 1 video files and most MPEG
     audio files.
   - mpgtx can fetch detailed informations from MPEG 1 and MPEG 2.
   - mpgtx can demultiplex MPEG 1 and MPEG 2 files (System layer, Program
     layer and Transport Layer).
   - mpgtx can add, remove and edit ID3 tags from mp3 files and rename mp3
     files according to their ID3 tags.
   - DivX ;) is not yet supported, neither is MPEG 4
   - splitting and joining of MPEG 2 video files is experimental. (read "will
     work only in your wildest dreams")

WWW: http://mpgtx.sourceforge.net/