Would be interested to see a comparison.. I use "gradient", I think most people do.
I'll reprocess one of my recent avi's using "compress" , and see what happens.
The quality estimator is used to determine the quality of each frame, so it ranks/sorts them in order after the "align" page, so that when you set your %, you get the best frames at the start of the list.
I guess it's an important feature
If you're using a method that doesn't measure the quality accurately, you could be throwing away good frames.
In the worst case, a different quality estimator might be better in different circumstances. That means someone needs to figure out which one is best in varying conditions
