  In this paper, The structure of video conference is formulated and the
peer-assisted distribution scheme is constructed to achieve optimal video
delivery rate in each sub-conference. The capacity of conference is proposed to
referee the video rate that can be supported in every possible scenario. We
have proved that, in case of one user watching only one video, 5/6 is a lower
bound of the capacity which is much larger than 1/2, the achievable rate of
chained approach in [2]. Almost all proofs in this paper are constructive. They
can be applied into real implementation directly with a few modifications.
