Invert Ultrakey selection
I need to make a mask of everything except for one color. It would be easier to create a Ultrakey, pick the color I don't need and invert it.
Example: I have a title and a red object moving on the screen. I use the video on V1; the text on V2; I duplicate the original video on V3, ultrakey the red object and invert it, so it would go on top of the graphic.