I wamt to mix two videos.  Does the composite object accept video?  If so how do you format the data?

I have had the experience mixing video with an analog mixer, and wanted to try to use Gem the same way?

is it possible to use the puzzle object with video?  What is the difference between the data types of video and tiff image?  

the multimage object could sort of do this, but not so good for live streams+labour intensive.