Alpha testing of video calls launched

The social network Vkontakte has launched a limited testing of video calls. So far, not all users of this social network have this opportunity. On December 31, 2011, the first million users received access; on January 12, 2012, the first ten million users.

I wonder if p2p technology is used for image transmission? How this was done, for example, with videos posted on users' pages.