[FFmpeg-devel] (i)(m)dct help for g.722.1

Benjamin Larsson banan
Thu May 17 12:48:09 CEST 2007

Michael Niedermayer wrote:
> Hi
>> Questions to the math gurus:
>> What's the best alternative FFT algorithm in terms of speed and accuracy 
>> that supports arbitraty sizes?
>> Is there a way to use the current code with some additional math 
>> (convolution, re-sampling) and produce accurate results?
> IIRC the only thing needed to do a 320 point FFT is that you write a
> 5 point FFT (the naive O(n^2) algo will do) and combine that with the
> existing 64 point FFT with the correct twiddle factors
> [...]

Here is a 5 point fft generated by spiral. Look at kiss fft how to
integrate both stages.

Benjamin Larsson
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