This filter cleans up the picture, averaging out visual noise between frames.

When colors change just a little, the filter decides that it’s probably noise, and only slightly changes the color from the previous frame. As the change in color increases, the filter becomes more and more convinced that the change is due to motion rather than noise — and the new color gets more and more weight.

The Settings

Noise Reduction

The higher you set it, the more you’ll cut down on noise — but the more blurring you will see. In general, reasonable settings range from 10 (to soften the occasional speckle without artifacts) to 20 (to reduce noise with minimal artifacts) to 40 (for better reduction, but visible blurring) up to 70 (to average out really heavy noise at the cost of bad blurring). At extremely high Noise Reduction values, you’ll start to see artifactual vertical lines.

To choose a setting for it, turn on just about any comedy or drama — anything with close-ups of moving faces. Increase Noise Reduction until the suppression of noise doesn’t seem worth the blur.

Fast Memory Access

This is a compatibility setting which should normally be turned on.

Noise Notes

You might want to take a look at Fun With Noise, a discussion of noise filtering in general.

Don’t run this filter at the same time as the Temporal Noise filter. Together they give you the “comical posterization and speckling” filter.

Filter changes

DScaler version 4.1 — Slightly changed the amount of blending to more closely approximate the calculated ideal. As a side effect, you may want to drop your Noise Reduction setting by a few ponits.