This is the extended sequence and trailer that aired (as far as I understand) with Agents of SHIELD last night. The teaser trailer portion that follows the teaser sequence appears to be the same trailer we have already seen — starting right after the Marvel logo in that trailer.
The teaser sequence here is pretty fun. It’s great to see the banter between the Avengers — maybe we can assume that they’ve had some small battle and victory over something. At the very end is when the big bad, or what will be the big bad, shows up. The scene has very much the feel of a Joss Whedon creation and I’m super excited. Who’s excited with me?!?