I want to create one artist as duplicates performing in the same scene for a music video how can I go about acheiving this in final cut hd or any other program?
You can either shoot them behind a green/blue screen and composite them together. Or you can do the oldest trick in the book "Splitscreen". Filming your actor on one side and them on a other side. split the, well you get the idea. I think your best bet is to shooting them behind a green/blue screen.
