From ILM's Official Youtube:
"We are proud to present this video which showcases some of ILM's Oscar nominated effects work for the 2012 hit film, "Marvel's The Avengers". This reel represents a small fraction of the work created by over 200 ILM artists, scientists, and engineers backed up by a world class production team.
The stop motion animations which open and close the reel were done the old fashioned way - by hand, one frame at a time. They were crafted by ILM's stop motion guru, Erik Dillinger specifically for this reel.