[FFmpeg-devel] Information about FFT implementation in ffmpeg

[Guillaume POIRIER]

Hello,

On Tue, Jul 26, 2011 at 5:38 PM, jogging song <joggingsong at gmail.com> wrote:
> Thanks for your timely reply, Vitor
>
> Today I find that FFT is followed by IFFT immediately, but the
> results is not same with original input data. The output is 16 times
> of original input data. Is this correct?

All FFTs behave this way (FFTW, MKL, CUFFT...). Chances are that the
number of elements you used as input was 16, right?

Just scale the output of FFT+IFFT by the number of elements and you'll be fine.

Best regards

Guillaume
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