A legitimate question. Haven't watched it and don't plan to, but video fakery is pretty well developed.
Though it would seem to be easier to film the real thing than fake it.
Obama himself hadn’t watched it. He said he was angry to learn about it (of course) but then didn’t bother to view it to be fully briefed about it before commenting (in a gray way about some sort of well can’t say Islamic extremists, call them ISIL and use vague phrasing to distance them of Islamist ideology...).