If Vegas allows you to have multiple video tracks, just put the footage you want to appear on the TV in a layer above the rest of the footage and scale/position it to fit on the TV screen. Use a corner-pin to distort it if the screen isn't being viewed directly head-on. You might also want to mess with the color of the "TV footage" to gum it up a bit so the quality is a tad different from the rest of the footage. As long as you don't have anything in front of the frame, you'll be fine.
EDIT: To see the above method in action, look at 7:40 in this clip. The computer screen was blank during shooting, and we put the images in entirely within Adobe Premiere. (Notice the jiggle at the end, and also how the computer screen cuts off part of our actor's face. I hadn't figured out how to use masks or motion trackers in AE yet.) It's not a perfect solution, but it's a simple and effective one.
Last edited by Noodle (April 16, 2010 (07:32pm))
With all due respect Noodle, I don't want you here. - Ratboy Productions