[FFmpeg-user] Documentation and feature request
astroelectronic at t-online.de
Mon Apr 15 23:58:21 EEST 2019
> 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.
thank you very much for this information. Some time ago I tested the eq
filter with high contrast values and had some problems, and then I
thought that's because the allowed range is [-2..+2]. Now I tested it
again and couldn't reproduce these problems. I just verified that two
cascaded eq=contrast=2 filters give exactly the same result as one
eq=contrast=4 filter. That's very good news!
I have one more question. Can you please explain the unit of the
What does brightness=1 mean? Does it mean add 256 to a 8-bit video, or
add 1024 to a 10-bit video?
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