mask_color(clip, color=None, thr=0, s=1)¶
Returns a new clip with a mask for transparency where the original clip is of the given color.
You can also have a “progressive” mask by specifying a non-nul distance threshold thr. In this case, if the distance between a pixel and the given color is d, the transparency will be
d**s / (thr**s + d**s)
which is 1 when d>>thr and 0 for d<<thr, the stiffness of the effect being parametrized by s