Hi all, i'm trying to add frames to do a kind of video feedback keeping in the background the previous frame while adding the most recent one. I have a chromakeyed video of mine. I'd like to find a way of adding a frame in a way that the black part of it (chromakeyed out) is just added while the colored part (kept in chromakeying) is superposed without adding. I think i have to create some masks, am i on the right track or is there a simple jit.op operation i can use but i could not figure our so far? Thanks Alberto