MaskTools/Binarize
From Avisynth wiki
Binarize(clip, [int "threshold", [bool "upper"]])
Plugin: MaskTools
The Binarize filter allows a basic thresholding of a picture. If upper=true, a pixel whose value is strictly superior to threshold will be set to zero, else to 255. On the contrary, if upper=false, a pixel whose value is strictly superior to threshold will be set to 255, else to zero.
Defaults are threshold = 20 and upper = true.
Back to MaskTools.