You of all people would be able to implement this easily if you knew exactly what it was. Nearly all video server systems outside of the lighting market use this feature as a standard. In QC you can make this happen easy.

When I get some time, I could put together a QC file illustrating the concept? I think you'll see that it's easier than how I explained it.

It's just a matte channel that travels with a key channel so you can have logos or any other "matted" out graphics run ontop of a layer or video input.

Just like trans black or white except totally different.

Christian