AVFoundation to overlay two video clips with Alpha compositing in ios5?
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I'm hoping to use IOS5 AV Foundation with or without Open GL to record video from the camera and overlay/merge another video clip on top using some form of alpha channel compositing / foreground matting.

A sample use case of the combined output may be a video of an animated character interacting with the the user's recorded video clip from the iPhone/iPad camera.

Is this possible right now with IOS5 or potentially with Brad Larson's GPUImage framework? Can the alpha channels of the two video sources be combined easily?

If anyone has any sample code they could share, or offer any guidance I'd be really appreciative.