* ffmpeg : add a new fourcc, ( 3IV2 you shoudln't be able to decode it

 * ffmpeg : add a new fourcc, ( 3IV2 you shoudln't be able to decode it
but sometimes it's in fact MPEG-4, thx titer ).

 * mp4 : add capability to read mov with mp3 track. But it seems that
mad doesn't like too much fragmented data packets, and thus breaks the
audio.( since with '--codec dummy' I'm able to read resulting audio file
without any problem :)