Use difference to decide which pixels to return from 2 clips?

basically, i am trying to work with two clips, let's call them a and b. what i want to do is (for each pixel): if a minus b is greater than a certain amount, use b for that pixel. otherwise, use a. i've already done it like this: Code:

beaten to the punch -G

oh, so what is the proper way to return the cloning effect? the reason i am trying to do this, is to merge two clips without "weakening" the areas where they do not agree, as is the case with simple averaging.

That's what I assumed that you are aiming for. Bad news is that's a difficult effect to achieve in a "proper" way. The naked pixel values don't give any hint which of both pixels should be used for the output pixel. Hey, c'mon: in frame N, you have a pixel with value "120". In frame N+1, that pixel has the value "160". Now, which to use for the output pixel? The "120" one, because it is darker? Why? The "160" one, because it is brighter? Why? It won't work that way. If at all, you'd have to compare the signal envelope, and use that one that has the bigger peak at the given location. But while that's more balanced, most probably it'll produce artifacts, too. Really, I don't see a "proper" way to achieve this without negative side-effecs.