I can't see the video but I'm going to guess from the description that it's oil from the mirror mechanism.
It's a known problem for some of the the other Canon DSLRs. The mirror mechanism is over oiled during production and the oil is flung onto the sensor. They don't admit the T2i has the issue apparently.
I'm on my second T2i in two days as a result of this. The first showed 4 spots within hours. They looked like small water spots.
I exchanged it for another T2i.
The second one is also showing these spots after a couple hours of shooting.
This one currently has 9 spots that are most obvious when shooting in movie mode.
My issue looks identical to the pic in the Canon service bulletin.
Anyway, here is the info on the issue with links to Canon's service bulletin.
I chose this link because it links to multiple Canon websites that address the issue.
http://www.robgalbraith.com/bins/content_page.asp?cid=7-10039-10074
Hope this helps.
Curt Massof
Room 39
