I'm not so sure that this 1024 points fft is optimal. I don't trust much
dist10 about the fft. After all, the original one was even computing
imaginary part, even if it's totally useless in our case.
A thing that I don't understand is how a 1024 points fft can be used for
1152 samples.
And what about using KLT?
Gabriel Bouvigne - France
[EMAIL PROTECTED]
icq: 12138873
MP3' Tech: www.mp3tech.org
----- Message d'origine -----
De : James (Jasha) Droppo <[EMAIL PROTECTED]>
� : <[EMAIL PROTECTED]>
Envoy� : lundi 24 mai 1999 00:41
Objet : Re: [MP3 ENCODER] misc questions
> Chris Matrakidis writes:
> >
> > > What about using the FFTW package instead of our fft. Perhaps it can
be
> > > faster? Perhaps Chris got an indication about this?
> >
> > The fft we have is quite fast and simple. There are faster ones (FFTW
is one of
> > the fastest as far as I know), but I the one I used was one of the
fastest and
> > simplest I could find and the only one that produced a binary identical
mp3
> > file with the original fft.
> > --
> > MP3 ENCODER mailing list
>
> The split-radix FFT that was "lifted" from Rico Malvar's book has "the
> lowest number of [real] multiplications and additions among all FFT
> algorithms [for N=2^k] known to date [1992]".
>
> If we assume that statement is accurate, then the only way to get a
> better FFT for N=2^k is to encode it more efficiently. That is, reduce
> the necessary shuffling of inputs and outputs, and/or re-organize the
> code to reduce cache misses, and/or make sure the processor's FPU
> pipeline doesn't "stall". Unfortunately, I don't have the expertise to
> do this. I just have enough knowledge to write the second sentence in
> this paragraph.
>
> I'm currently working on implementing a N=4^k algorithm which can be
> up to twice as fast as the N=2^k algorithm. Lucky us, 256=4^4, and
> 1024=4^5.
>
> --
> James 'Jasha' Garnet Droppo III [EMAIL PROTECTED]
> Interactive Systems Design Lab ISDL:(206)543-7298
> Department of Electrical Engineering, University of Washington
> http://isdl.ee.washington.edu/isdl/jdroppo/
>
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> MP3 ENCODER mailing list
>
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