[HELP] about grain

[Selur]

Also, the current script is causing the grain to extend beyond the white areas, which looks bad.

Yes, that is what all those

mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().mt_expand()

in Avisynth and:

for i in range(11):
  white_mask = white_mask.stdMaximum(white_mask)

in Vapoursynth will do.
=> remove those parts if that is not what you wanted.

For a specific color mask, use: https://github.com/Beatrice-Raws/VapourSynth-TColorMask instead of BinarizeMask with a threshold.

Cu Selur