Hi,
I am interested in and have searched mathematical theory about
aliasing reduction buttefly in MP3.
But I cannot find the good paper to explain the mathematical basis of that.

I hope to confirm how the coefficients were introduced for MP3.

If you know the paper or homepage about that, could you teach me ?


For your reference:
I made a homepage about mathematical proof of MDCT and polyphase filter bank
but sorry in Japanese.
See
http://www9.ocn.ne.jp/~hkato111/
--> 1. to 11.

So far you have received no responses. I'm sure I can't help directly, but is it possible you are using terminology not common in the west, where most HA forum members seem to be? The fact that I never heard of an "aliasing reduction buttefly in MP3" doesn't in itself mean anything, but I've done casual reading on aliasing and alias reduction from time to time (not in regard to mp3, however). I've never run across a single mention of "butterfly" in relationship to the subject. Is it possible that most people might know this by a different label?

A butterfly is a kind of operation, its used in DFTs a lot. I believe the one in MP3 is used in the IMDCT stage, but thats all I know (MP3 is a mystery to me).

This page mentions a little on it:
http://www.es.lth.se/home/tlt/publications/masterthesis.pdf

(section 2.3.7)

Not much, but maybe helpful.

For an introduction, see

http://www.mp3-tech.org/programmer/docs/paper-1-english.pdf

page 53 and later.

Thank you for your suggestion and kindness.
I will try to explain the coefficients.

Thanks again.

H.Kato, Japan