I remember seeing a 768 points FFT somewhere just before an adaptation of
KLT for mp3 encoding.
The problem is to remember where I saw it.
Regards,
Gabriel Bouvigne - France
[EMAIL PROTECTED]
icq: 12138873
MP3' Tech: www.mp3tech.org
----- Message d'origine -----
De : Mark Taylor <[EMAIL PROTECTED]>
� : <[EMAIL PROTECTED]>
Envoy� : lundi 24 mai 1999 07:16
Objet : [MP3 ENCODER] FFT's in LAME
>
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> I think Chris' FFT is down to about 3% of the total cost. So even if
> we found an FFT that was twice as fast (very unlikely), it would only
> save 1.5%. Thus I dont think linking to a big package like FFTW is
> worth the trouble.
>
> Just to clarify some other points:
>
> layer3 works with 1152 sample 'frames', but all the analysis is
> done on two 576 sample 'granules'. Except for the frame header
> information, the two granules in each frame are completely independent.
> For each 576 sample granule, the psy-model does one 1024 FFT centered
> over the granule, and 3 256FFT's centered over each third of the
> granule. So I dont know if 1024 is really optimal, maybe 768 would
> have been a better choise.
>
>
> Mark
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