[FFmpeg-devel] [PATCH 0/4] fftw exploration (WIP)

Ganesh Ajjanagadde gajjanag at gmail.com
Fri Mar 25 17:44:53 CET 2016

On Fri, Mar 25, 2016 at 9:36 AM, Nicolas George <george at nsup.org> wrote:
> Le sextidi 6 germinal, an CCXXIV, Ganesh Ajjanagadde a écrit :
>> Depends on if it is small or not. Yes, in many codecs, FFT's are short
>> length ones, e.g 512. However, on long lengths, e.g 8192+, as seen
>> from the benches, there are sometimes 2x variations at the moment.
> And how much of the actual total decoding is spent in the FFT? Even a ×50
> speedup would be useless if it is for a function that never amounts to more
> than 0,01% of the actual time. The FFT is probably not that negligible, but
> this is not a ×50 speedup either, and I have no idea how frequent are long
> lengths.

Paul had some interest in 2^17 fft's at a point.

> You often do your benchmark like that, please try to be more careful and
> benchmark spans of code that are actually relevant for FFmpeg's tasks.

Will keep in mind, thanks.

> Regards,
> --
>   Nicolas George
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