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

Måns Rullgård mans
Thu Aug 16 23:32:04 CEST 2007

"Guillaume POIRIER" <poirierg at gmail.com> writes:

> Hi,
> On 8/16/07, Michael Niedermayer <michaelni at gmx.at> wrote:
>> On Thu, Aug 16, 2007 at 04:41:21PM +0200, Guillaume POIRIER wrote:
>> > Well, don't forget that according to Michael, FFmpeg's FFT sucks, so
>> > writing a fixed-point version of a sucky implementation may not be so
>> > wise :-(
>> dont fear ill revert any cooley tukey fixed point FFTs which get commited
> Hehe :)
>> which brings us back to what i already said ... someone should implement
>> a split radix fft (changing the current float fft to split radix would
>> surely be nice as well...)
> I have a question regarding the API of FFTs:
> When I made my review of the state of the art, I noted that FFTW, IPP
> and MKL seemed to offer only a pair of Real and Imaginary arrays to be
> passed to their computation functions, whereas FFmpeg's API supports
> only an array of pair of Real, Imaginary numbers.
> So it looks like this:
> fft_mkl(double *real_array, double *imaginary, int size)
> fft_ffmpeg(struct_complex *pair, int size)

FFTW also supports the C99 complex type.

M?ns Rullg?rd
mans at mansr.com

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