@Airw0lf: u need to enable "Divx4" decoding in ffdshow, coz that mp4 is MPEG4 part2 (advanced)simple profile (aka Divx5/XviD, but their FOURCC is MP4V), not h264/AVC. those Nero Digital mp4 trailers is also MPEG4 (advanced) simple profile. that message seems identical but only the "subtype: Unknown GUID Name {31435641-0000-0010-8000-00AA00389B71}" is different, and "31435641" is FOURCC in HEX format, convert the hex form to ASCII is 1cva (spell backwar will be avc1)