[FFmpeg-user] fftfilt

[Michael Koch]

Am 14.10.2021 um 16:13 schrieb Michael Koch:
>
> This is the command line for the lowpass filter, where the filter 
> freqency isn't a function of input size. The constant "8" is the 
> filter wavelength in pixels per linepair.
>
> ffmpeg -i test.png -vf 
> scale=2*iw:2*ih,fftfilt=dc_Y=0:dc_U=0:dc_V=0:weight_Y='lte(hypot(X/pow(2,ceil(log(ceil(W*10/9))/log(2))),Y/pow(2,ceil(log(ceil(H*10/9))/log(2)))),1.0/8)':weight_U=1:weight_V=1,scale=iw/2:ih/2 
> -y lowpass.png
>
> With two new variables for the FFT array size
>
> ARRAY_H = pow(2,ceil(log(ceil(W*10/9))/log(2)))
> ARRAY_V = pow(2,ceil(log(ceil(H*10/9))/log(2)))
>

Thanks for the patch. I will test it in a few days.

Michael