[FFmpeg-user] Documentation and feature request

Gyan ffmpeg at gyani.pro
Mon Apr 15 19:10:01 EEST 2019

Hi Michael,

I'll look at these in detail later on, but just to touch on one point..

On 15-04-2019 06:15 PM, Michael Koch wrote:
> "eq" filter:
> -- It might be helpful to add a note that multiple eq filters can be 
> cascaded, for example if contrast enhancement bigger than 2 is required.

Contrast can go from -1000 to 1000. The range was expanded a few years 
ago; the doc wasn't updated.

Do note that what contrast does is scale the distance of a pixel's value 
from the median value i.e. 128 for a 8-bit input. So, if a pixel channel 
has a value of 100, then a contrast of 3 results in a value of   128 + 
3*(100-128) = 44.

The order is contrast -> brightness -> gamma.


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