MSmooth

The MSmooth Avisynth plugin implements an unusal concept in spatial smoothing. Although designed specifically for anime, it may be useful elsewhere. The filter is effective at removing mosquito noise as well as effectively smoothing flat areas in anime. Not only is the noise reduction valuable, but less bits are needed to encode the resulting clip.

The justification for the filter is simple. The biggest complaint about Smart Smoother (for example) is that setting the threshold high enough to give the desired smoothing destroys a significant amount of detail.

We need to decouple the control of detail detection from the amount of smoothing applied. In Smart Smoother and other thresholded smoothers, one threshold controls both of these functions.

Also, smoothing should not be done across image edges. MSmooth implements both of these refinements. To use it, first set the 'threshold' parameter so that desired detail is preserved. Then set the smoothing strength.

You can set very high smoothing strengths without destroying the preserved detail (because the detail map is used to mask the smoothing).