I tried again to test Color Space plugin and noticed some peculiarities:
If I set Input: BT709 and Output BT709, and also BT2020 -> BT2020;
then the result is not clipped. Any other combination of Input/Output
leads to a clipped result instead. How can this be explained? Perhaps
the input is not clipped (apart from BT601 which is always clipped),
but every transformation is always clipped. 709 -> 709 and 2020 ->
2020 does not perform transformations and thus remains unclipped.
This argument can perhaps also be carried over to the “YUV Color
Space” tool:
my understanding this is not a tool per se, more like switch for ffmpeg (libswscale) colour conversions ...
happens on both input (if ffmpeg selected) and output ....
As I noted there is some CMS/floating point/swscale rework in upcoming ffmpeg 8.0 , so if things will not break in many other ways we might try to convince swscale to not clip on import at least.