Internal filter "gamma correct" is doing srgb to linear or reverse conversion. It works with rgb64, and 6-axis correction too (but I just discovered there is color error in x64 build, so if you try it make sure to use x86 version).
convert format to 16-bit yuv (needed to avoid some banding)
convert format to rgb64
gamma correct
...
full project (should work if you save it in same folder where mp4 is).
https://gist.github.com/shekh/3b3a97...1170-vdproject