Overlaying effect - how to ?

[qazxsw213]

I struggled to get to know how to gain similar effect to this video : http://www.youtube.com/watch?v=wzsVvQYA26Q
I mean i would like to overlay some person to video which is not a part of another video, any ideas ?
( i use such software like sony vegas and after effetcs, i can't find this option which could give me possibility to do it)

[jagabo]

Go to Youtube and search for "vegas chroma key". For example:
http://www.youtube.com/watch?v=HYX9DTfn9ZM

[qazxsw213]

thank you it helped me, i didn't know what kinda of function to use