This effect/filter replaces the pixel by the local(3x3) minimum giving the source image an erosion effect.
The effect does not have keyframes.
1st / 2nd / 3rd / 4th Plane Threshold - Limits the maximum change for each plane, default is 50. If 0, plane will remain unchanged.
Coordinates - Flag which specifies the pixel to refer to. Default is 255, i.e. all eight pixels are used.