[FFmpeg-devel] Fwd: Fixpoint FFT optimization, with MDCT and IMDCT wrappers for audio optimization

Benjamin Larsson banan
Fri Aug 17 15:58:16 CEST 2007


Michael Niedermayer wrote:
> Hi
> [...]
>   
> dont fear ill revert any cooley tukey fixed point FFTs which get commited
>   

Ok, then you can start by reverting revision 5. 
http://svn.mplayerhq.hu/ffmpeg/trunk/libavcodec/ac3enc.c?view=markup&pathrev=5

I don't see it as obvious that a split radix fft would be faster on 
every fixed point platform out there. Would it really hurt to have 
several fft algos available in the source? Without a radix-2 algo we 
wouldn't have anything to compare against to back that claim anyway. I'm 
not really doubting that a split radix fft would be faster in most cases 
but I'd rather let the benchmark numbers prove the point.

MvH
Benjamin Larsson






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