[FFmpeg-user] Best place for despill filter?

[Michael Koch]

Am 16.11.2020 um 12:22 schrieb Paul B Mahol:
> On Mon, Nov 16, 2020 at 12:13 PM Michael Koch <astroelectronic at t-online.de>
> wrote:
>
>> When I overlay a bluescreen foreground video over a background video,
>> which is the best place for the despill filter? (a) before colorkey or
>> (b) after colorkey or (c) after overlay?
>>
>> [foreground](a),colorkey,(b)[fg];[background][fg]overlay,(c)
>>
>> I found here an example for (c) but I doubt that this makes sense:
>> https://gist.github.com/kerbeh/fbe0cd0d89c424708c119e0a0d00ca88
>>
>>
> Why do you doubt that it does make sense?

I doubt that (c) is the right place because at position (c) the despill 
filter also affects the background video, which surely doesn't have any 
contamination from the bluescreen.

Michael