AAC

As there is MP3, there must have been a MP2 and a MP1.
Of course an MP3 player should play all of them.


One day, they decided to drop this backwards compatibility.
If all knowledge obtained while developing MP3 could be used without the historical ballast what would be the result?
That is AAC, Advanced Audio Coding.
It achieves transparency at a lower bit rate than MP3.

 

If you are in need of a lossy compression (portables), AAC is a better choice than MP3.

 

Some people think is is an Apple owned format, it isn't.

 

It is very good in preventing generation loss when doing multiple passes.


Other differences:

References

  1. Advanced Audio Coding - Wikipedia
  2. HTML5 AAC Audio Playback Tests -  Fraunhofer