Multiply the video with a scalar with FFMPEG

Question

I have to adjust a video which was too dark. In openCV, I simply used Img.Mul() to multiply each of the RGB band with a same scalar and got good result.

Could one do the equivalent operation with FFMPEG? I tried eq with contrast and brightness, but it was not quite the same thing.

Edit : thanks to a clue in @VC.One's answer below I was able to emulate Img.Mul() with:

ffmpeg -i input.file -vf colorlevels=rimax=0.5:gimax=0.5:bimax=0.5 -c:a copy output.file

Answer 1

Sounds like you want to increase the levels of pixel brightness.

You can try: https://stackoverflow.com/a/58738185/2057709

If you've worked with image curves (in some photo editor) then also try: https://video.stackexchange.com/a/13110/17929

curves=r='X/Y':g='X/Y':b='X/Y'

The above curves method is nearest to increasing the input of each RGB channel.
Where the X and Y are numbers ranging from 0.0 up to 1.0 .
I recommend X of 0.5 and then you can test for the right Y value.