[FFmpeg-devel] av_resample_init() optimization

Olivier Guilyardi list
Fri Jan 8 18:55:39 CET 2010

On 01/08/2010 03:32 PM, Michael Niedermayer wrote:


> as said if you want speed use a lut and cubic interpolation
> this would make the code >10x faster. There are probably other ways to
> make it faster but you are optimizing the wrong code (that is float code
> on a fpu less system with a very poor fpu emulator)
> You could also look at libavutil/softfloat* which should be faster for
> doing float calculations
> also the 0 check should make less of a difference after my recent changes

Yes indeed, your changes to bessel() at r21038 result in 3.6s initialization
instead of 6.9s. That almost 2 times faster.

I'll see what I can do with cubic interpolation, and softfloat (although it
lacks sin(), cos(), sqrt(), etc..).

Thanks for your help and this great resampler.


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