An alpha channel is an additional set of information that resides in the movie or still that tells the pixels whether they should be transparent, opaque or semi-transparent. This allows for overlays graphics on top of other media. In your editing program, just put your main footage on the bottom layer and your media with aloha above that. If you use a alpha channel compatible format, the editing program will automatically apply the alpha channel to the clip allowing you to see through it to the lower layers in your timeline. Steve
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