tmix and scale, different brightness depending on order
I found a problem while I was experimenting with the haldclut filter.
But it's simpler to reproduce without haldclut. The input video contains
10 seconds of noise (10-bit) and can be downloaded here (2MB):
My command line compares two cases with hstack.
Left side: first tmix filter, then scale filter
Right side: first scale filter, then tmix filter
In the output video you can see that the right side is darker. I don't
It's not a big difference and only visible with strong contrast enhancement.
But the error was big enough to make my haldclut useless.