CombinePlanes: error when sample clip is a different dimension but compatible colorspace.

[Reel-Deal]

src = ColorBarsHD()
y = src.ExtractY().ReduceBy2()
u = src.ExtractU().ReduceBy2()
v = src.ExtractV().ReduceBy2()
CombinePlanes(y, u, v, planes="YUV", source_planes="YYY", sample_clip=src)

Throws an error: "CombinePlanes: source and target plane dimensions are different" although the colorspace is compatible.

Currently sample_clip is documented as "If supplied, output pixel_type will match that of sample_clip." so it should not care about the dimensions, only the colorspace, if compatible.

[pinterf]

The documentation is not perfect. The exact dimensions must match. Checking 4:4:4 would be easy, but let's take a YV12, then Avisynth would have to check that the passed chroma plane dimensions are proportionally O.K. for the given Y.
I guess sample_clip = src.ReduceBy2 would work in general.

[Reel-Deal]

I'll have to clarify that in the documentation then. Speaking of that, I'll leave this open since I have a few questions for the documentation that I would be grateful if you expanded on some of the behavior.