[FFmpeg-user] How to correct dark video with bright background

[Michael Koch]

Am 10.03.2019 um 22:05 schrieb Michael Koch:
> Am 10.03.2019 um 21:33 schrieb Gerardo Ballabio:
>> Thank you Michael -- but that means I still have to find good values
>> of brightness, contrast, gamma, saturation and hue to use with Gimp.
>> When I've done that, then couldn't I just apply the same values in
>> ffmpeg using the "eq" filter?
>
> That won't work because in most cases the values for brightness, 
> contrast, saturation and so on don't have the same units in different 
> programs.

Also you can't be sure that different programs apply the filters in the 
same order. Applying brightness before contrast doesn't give the same 
result as contrast before brightness. It's an addition and a 
multiplication, and it's important what's done first.

Michael