commit 4e9b4a1570177148d49de3411a6d6733394fa757
author Yaowu Xu <yaowu@google.com> Wed Dec 21 12:05:10 2011 -0800
committer Yaowu Xu <yaowu@google.com> Wed Dec 21 12:05:10 2011 -0800
tree db2909ac32f9b9d9627083f4d31fddd1103c0876
parent 5920b520a01574525dc279cad37087e604c1f212

changed mode_context update strategy

Previously, the mode context is always udpated based on stats of current
frame, when there is no count, 50% is used for both left and right branch.
However, it is observed that with such strategy, a small count or no count
at all can skew the probability distribution significantly. This commmit
changed the mode_context update strategy to prevent small counts from
skewing the probability distributions.

Tests on derf set showed a small gain:  .06% in psnr and .09% in ssim

Change-Id: Ic812e64ae5f70251c170b0717f7b7fa587055488