Superimposing faces?? Please advise!!

[bertonly]

Hi all,
Im wondering if theres any software out there that would let me superimpose a face on another body----not onto a still image,but moving image video.
I guess something like forest gump.Its probably pretty tedious,but Im talking about
very small clips(5-10 second long.Any software or technique that anyone knows of would be great to know!!! Thanks !!!

[guns1inger]

Pretty much any good NLE (Vegas, Premiere) can do it, as can WAX2. Compositing programs can make life easier by actually tracking the original faces for you (After Effects, Combustion etc). Actually superimposing is simple - you need the replacement face and a mask (usually either black and white or black and transparent). If the person is facing the camera the whole time then you don't even have to deal with angles.

If you have to do it by hand (and with most NLEs you will because they don't have built-in trackers) then you need to look at motion tracks and keyframes.