[FFmpeg-user] fftfilt

[Michael Koch]

Am 14.10.2021 um 12:53 schrieb Paul B Mahol:
> On Thu, Oct 14, 2021 at 12:29 PM Michael Koch <astroelectronic at t-online.de>
> wrote:
>
>> Am 14.10.2021 um 12:07 schrieb Paul B Mahol:
>>> Sorry but I'm not on windows, so I can not use your script.
>> Then try the below (slightly improved) version. It would become much
>> simpler with variables:
>> ARRAY_H = pow(2,ceil(log(ceil(W*10/9))/log(2)))
>> ARRAY_V = pow(2,ceil(log(ceil(H*10/9))/log(2)))
>>
>> The test image contains wavelengths from 4 to 8 (in the center) to 16
>> pixels per linepair.
>> The filter wavelength is independant of input size. You can change the
>> size in the first command (but it must be 1:1 aspect ratio, otherwise
>> hstack would fail)
>>
> Since when hstack fails because of different aspect ratio?

Because I first make the left half of the test image, then transpose it 
and then hstack them together

The fftfilt examples do of course work with any aspect ratio.

Michael