[FFmpeg-devel] ac3 imdct question

[Benjamin Larsson]

Arpi wrote:
> Hi,
>
> Could someone DSP guru please explain me, what ff_fft_calc exactly
> calculates in ff_imdct_half_c() of mdct.c ?
>   

Do I miss something obvious, ff_fft_calc should calculate the fft of a 
complex buffer of floats.

> I've tried to replace it (for experimenting with pitch correction...)
> with the 'standard' inverse discrete fourier transform but it does
> not work, the sound (ac3 music sample file) gets heavily distorted :(
> here's my modification:
>   


Replacing the fft with a dct will not work.

MvH
Benjamin Larsson