(Sorry If I am not in the right Section...dont know wichone i should post this in...)

Anyways, Guys i rly need help with this thing...
u know the way, u can kinda close peoples faces in any video...so other people wouldn't recognize them?
Please can someone tell me how to do it..or send me a link to a Tutorial...on you tube please..I rly need to know how to do this...Thx and Hope someone can help me.

/ohshi t