Intergrating FLV with flash setInterval -hOW 2?

Hi flashfellas

I want to know how adidas added the ““Player - Pope”” movie (flv) to work smoothly with time.
Enter Site

Another example is Wendy’s
After some time without mouse activity the video will play different animation

I think they use a green screen to capture the video, then extract. Layered over the background movie clip. And use setInterval method to play the flv. However the movieclip is smooth…

hOW 2?