How to enable GPU for MCTemporaldenoise filter?

[Selur]

2) Selecting any weighing function other than the default (Welsch) seems to cause no effect on the output file. That is, I see the GPU working, the encoding finishes with no errors, but the output file doesn't get denoised at all, and visually seems identical to the input file. Even if I crank up the denosing strength.

I can reproduce this (only tried one sample), from the looks of it Hybrid properly sets wmode, so this a bug in the filter or some of the other parameters need to be adjusted for those modes to work properly.
Best complain to the author of the filter over at https://github.com/Khanattila/KNLMeansCL/issues (or over at doom9s), doesn't seem like a bug in Hybrid.

1) Selecting any channel other than "auto" or Y gives an error. If I select YUV or UV, the encoding crashes with a message that the filesize is too small. I'll send the debug log if you need, although you could probably replicate it yourself.

Opened a YUV (Yv12) source and tried Y/UV/YUV and got no error.
(Note that for high bit depth, color is always converted to RGB30
Selecting 'RGB' throws an error, same will probably happen when the source is RGB and not YUV and you select a YUV color mode.
I added a workaround for this by adding an additional color conversions.
-> send you a new link to a dev version for testing which does these conversions.

Cu Selur