hi, with mp4create (mpeg4ip.sf.net) you can create mp4 files with mp3 audio stream (rfc 3119) but mplayer will not recognize the mp3 stream. adding the format 0x6134706d to my codecs.conf, i was able to play the movie with mplayer -ac mp3 movie.mp4 without -ac, mplayer will try to decode AAC jan