Reinterpolation411-style script insertion

[Selur]

During my workflow I then ran across clips with vertical banding in source files and read a thread about reinterpolate411 and chroma cleanup. The common theme appears to be indoor lighting and maybe static shots inducing this effect.

If you can share said clip, I can take a look at it.

About your function:
Instead of:

# Separate planes
y = core.std.ShufflePlanes(clip, 0, vs.GRAY)
u = core.std.ShufflePlanes(clip, 1, vs.GRAY)
v = core.std.ShufflePlanes(clip, 2, vs.GRAY)

# Reduce to even columns
u_even = core.std.SelectEvery(u, cycle=2, offsets=[0])
v_even = core.std.SelectEvery(v, cycle=2, offsets=[0])

# Resize to full width via horizontal interpolation
u_interp = core.resize.Bicubic(u_even, width=clip.width, height=clip.height, src_left=0.25)
v_interp = core.resize.Bicubic(v_even, width=clip.width, height=clip.height, src_left=0.25)

# Merge back to YUV
return core.std.ShufflePlanes([y, u_interp, v_interp], [0, 0, 0], vs.YUV)

better use:

# colorformat YUV444P8

# Separate planes
[y, u, v] = core.std.SplitPlanes(clip)
# Reduce to even columns
u_even = core.std.SelectEvery(u, cycle=2, offsets=[0])
v_even = core.std.SelectEvery(v, cycle=2, offsets=[0])

# Resize to full width via horizontal interpolation
u_interp = core.resize.Bicubic(u_even, width=clip.width, height=clip.height, src_left=0.25)
v_interp = core.resize.Bicubic(v_even, width=clip.width, height=clip.height, src_left=0.25)

# Merge back to YUV
return core.std.ShufflePlanes([y, u_interp, v_interp], [0, 0, 0], vs.YUV)

But this only makes sense if in your source "the odd chroma pixels are duplicates" otherwise your chroma will be wrong.
Here's an example, where I took a normal 4:1:1 DV file and applied that code:https://imgsli.com/MzkwMjY2

=> You probably should not use this or similar code.

Reading http://avisynth.nl/index.php/ReInterpolate411 again, you might notice that this is not meant to be used on 4:1:1 content, but it is meant to be used on YUY2/YUV4:2:2 content where the 4:1:1 => 4:2:2 conversion was done improperly.
Side note: one could use ReInterpolate411.dll by switching to Avisynth 32bit (requires an addon) in Hybrid and then load and apply that filter in a custom script.

Cu Selur