AviDemux/VapourSynth

[mean]

Confirmed, U & V are inverted

[YAFU]

Ok 
So this would be the script to reduce noise with KNLMeansCL using OpenCL if anyone is interested:

Code Select Expand

import vapoursynth as vs
core = vs.get_core()
##
##ffmpeg with ffms2
src = core.ffms2.Source(source='/PATH_TO_VIDEO_HERE/input.mp4')
##

YUV = core.fmtc.matrix(clip=src, mat="601", col_fam=vs.YUV)
YUV = core.fmtc.resample(clip=YUV, css="420")
YUV = core.fmtc.bitdepth (clip=YUV, bits=8)

clip = core.knlm.KNLMeansCL(YUV, d=3, a=2, s=4, h=4.2, device_type="GPU")

clip.set_output()


This is the documentation for parameters:
https://github.com/Khanattila/KNLMeansCL/blob/master/DOCUMENTATION.md

I clarify that I do not know if the script is well designed, but it seems to work.