mpeg 4

It depends on the movie and receiver. The formats are either MPEG-2 or MPEG-4. Our HD receivers are in MPEG-4 and the other receivers are in MPEG-2. Eventually they will all be in MPEG-4.

MP4 is often referred to as MPEG-4, MPEG-4 Part 1, MPEG-4 Part 14 or MPEG-4 Part 12. Common extensions for MP4 files are .mp4, .m4a, .m4p, .m4b, .m4r and .m4v.

MPEG-4 audio files can be imported to iTunes 9. They will usually have the extension .m4a or .mp4. The AAC files that you can purchase from the iTunes store are MPEG-4 audio files.

Because you have a MP3 player that can only play MP3 audios, but M4A can't play on a MP3 player because M4A is an MPEG 4 and your MP3 player is a MPEG 3.

The MPEG 4 is to powerful or high for the MPEG 3 (4 is bigger than a 3).