Wow, I don't know why the following AviSynth code works, but it seems to get rid of the over-represented reds in (at least, PAL) GOUT. I think it may have something to do with re-sampling. Can someone with more experience in color-correction chime in, please?

y = gout.MergeChroma(gout.BlankClip(), 1)

rgb = gout.MergeLuma(gout.BlankClip(), 1).ConvertToRGB24(matrix="Rec601").ConvertBackToYUY2(matrix="Rec601")

y.MergeChroma(rgb, 1)

It assumes that ``gout'' is in a YUV color-space; e.g., YUY2 or YV12.

(Note: I was trying to get Blackmagic Design's YRGB color-space in AviSynth when I discovered this.)

Edit: Of course, the colors will have to be Tweak()'d to get them right.

Edit 2: I may have jumped-the-gun here.