The MPEG4 in the support list refers to video.
There are actually 23 parts in the MPEG-4 specifications. The supported part is part 2 (Advanced Simple Profile video like XviD) and even that is limited.
AAC audio (possibly MPEG-4 Part 3, or MPEG-2 Part 7) is not supported. Neither is the MPEG-4 file format (.MP4) defined as MPEG-4 Part 14
