I know mp4 is supposed to have 'higher sound quality at a lower file size', but:

  • how does it do this? How does it compress more information into a smaller space?
  • How much of mp3 is still used? Was mp4 completely designed from the ground up, or does it improve on the mp3 format?
  • Are there any other improvements or differences over mp3?
  • 4
    They aren't related at all.
    – Brad
    Jan 19, 2011 at 4:40
  • Tobylane seems to have elaborated sufficiently. Is there something you need clarification on?
    – Brad
    Jan 19, 2011 at 23:53

2 Answers 2


Mp3 is "MPEG-1 or MPEG-2 Audio Layer 3 (or III)" and MP4 is "MPEG-4 Part 14". Mp3 is an audio compression and file type, mp4 is a file container capable of holding any video compression (e.g. h.264). So MP4 isn't an extension on MP3 like a bucket isn't an improvement on sand. Read the wikipedia articles for more information.


  • It would be helpful if you included links to the wikipedia articles you referenced.
    – BenV
    Jan 18, 2011 at 20:56

What you're thinking of is AAC, not MP4. MP4 is often used as the container for AAC-compressed audio.

AAC uses many of the same principles as MP3, essentially throwing away frequencies that the listener probably won't miss. The main difference between the two is which frequencies each chooses to throw away. AAC was basically "let's take what we learned from MP3 and design something even better".

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