[MPlayer-dev-eng] [PATCH] AF Pitch filter

Charlie Brej mplayer at brej.org
Mon May 28 16:44:36 CEST 2007


Guillaume POIRIER wrote:
> Hi,
> 
> On 5/28/07, Reimar Döffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> wrote:
>> Please try to use one of the fft functions in libavcodec, I don't really want
>> to waste our time by
>> 1) reviewing this code
>> 2) finding someone who can tell us if these conditions are compatible
>> with the GPL.
> 
> Two more things:
> 3) libavcodec's FFT has already some parts optimized with
> MMX/SSE/Altivec, so we don't really want to duplicate this effort.
> 4) Now that you proved that your pitch filter works with an FFT that
> you know how to use, it shouldn't be too hard to port it to lavc's,
> which is also supposed to work, though U ca

The problem with the lavc FFT code was that it uses pow2 sized data 
arrays. I rewrote the filter to use this but the resultant sound is not 
as good as with the kiss code. This can be corrected by tweaking with 
the wave offsets. The 1x and 2x ones sound pretty good but the others 
have a bit of echoing. This can be tuned later.

The new patch is attached.

Additionally, some parts of the code are not optimal, I left them in 
this state to allow the code to be tuned before it is optimised.

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