Hi! I am trying to create an effect that I can bring into my timeline in avid and place over the video--and I have a hard time getting rid of the black. It isn't keying. How do I save the effects I make to a MOV file so that they are keyable? SOmething with alpha but I don't know how. PLease help.
You are essentially not saving the effect with an alpha.
Make your effect, press the red Export button, select AVI as your file type (or QuickTime on a Mac), and make sure that you select the Alpha option as well.
Save it out, then import it into Avid (you might have to invert the alpha on import).
No need for keying.
It can get a lot more intricate then this, but this is the basic way, and you'll find help on this in the Tutorials you get with the software.