Final Cut Pro X: green key I've recorded a video clip with a TV in the background. During the recording, I displayed a green key on the TV. Now, I want to replace the green color with a picture I captured. It's an almost perfect rectangle. The camera is moving a little bit and is zooming in, making the TV (and the picture to display) a little bit bigger. 

I figured out how to replace a green key background, but this doesn't do the trick in this case, because the picture I replace the color with is moving and resizing.

Any tips on how to do something like this?
I ended up using Apple Motion, which did the trick fairly well. You can select tracking points which the software tries to follow during the video.