The setting works on all sources (Blu-ray, cable tv, etc) and will clean up noise and other artifacts in an image. It works well for cable/satellite (removes compression artifacts and whatnot). Not necessary on 4K sources unless you don't like movies with high film grain. Low is less aggressive than Auto. You will likely want to set it to Off or Low for 4K sources because it will sometimes smooth the picture out too much on Auto and you'll lose details that are present in a 4K image.What is the difference between Digital Clean Auto and low? also does it work on blu ray/dvd or only through cable TV?