Hello,

While looking around for some MP3 documentation I have came across the following sites:

• MP3' Tech
  
• ID3.org

As you can see, the bitrate tables are different. ID3.org says that MPEG 2 Layer 2 varies between 32 and 384, while MP3' Tech says that it varies between 8 and 160. Which of the two tables is correct?

Regards,
Sebastian Mares

I should go back and read them again if I were you. They say the same thing. You're confusing the Version number with the Layer number.

Actually, I don't!

MP3' Tech says that the lowest bitrate for MPEG 2 Layer II AND III is 8 kbps, while ID3.org says that ONLY MPEG 2 Layer III starts at bitrate 8 kbps.

Hmmm, I think my brain must have been out to lunch!!

I would tend to trust Gabriel's (mp3tech) since he is a LAME developer.

I shall resist against making some mean, sarcastic remarks about the intelligence of the creators of id3v2.

Yes...

My copy of the ISO standard gives the same numbers as me.

I checked id3.org, and they are listing the mpeg2 bitrates for layer I and II to be identical to mpeg1 ones.
This is wrong in case of use of mpeg2 low sampling frequencies.

Anyway, layer II lsf should be quite rare. In the standard, the table listing the allowed stereo modes (as in mpeg1) is missing.

It seems that the ISO comitee though about the following:
*if you want to reduce bitrate, then use layer III and not layer II
*if you want multichannel, use layer II, as it's less complew than layer III

Layer III multichannel seems to be completely defined in the standard, however there is no encoder. Even in the ISO compliance bitstreams, there is only 1 layer III mc test sample, and this one is synthetic (not produced by an encoder)

Thanks for the information Gabriel!

By the way, would it be possible for you to have a look at this tread and maybe answer some of my questions, please?

Best regards,
Sebastian