sorry to burst your bubble, this isnt about the halo 3 movie thats coming out. this is a teaser for the game.
If im correct this video is from the production studio that is going to make the Halo Movie. It is not necessarily a teaser its more of a short film for people to get the feel for the movie... If anything its a teaser for the movie.
OMG I tried to watch it, took forever, and when it was ready it says it's missing a codec. I'm not gonna download a codec to watch a short movie lol xD