commit fab16037d92821230cce636cfae053159b3e7d74
author Jingning Han <jingning@google.com> Fri Dec 16 14:52:45 2016 -0800
committer Jingning Han <jingning@google.com> Mon Dec 19 16:30:38 2016 +0000
tree 68d17eca4ee3975a5e33a0515fa2c32caebc318a
parent ed8f3964519a006c40a22bcfdd5f5a01149882f5

Scale reference motion vector search step size

This commit allows the dynamic motion vector referencing system to
scale its search range according to the coding block size. This
provides higher search resolution for smaller size coding unit.

The cb4x4 mode improves the compression performance across all the
test sets:

         avg     low    mid    high
lowres   2.8%    2.4%   3.1%   3.0%
midres   1.3%    0.3%   1.8%   2.7%
hdres    0.9%    0.5%   1.4%   1.5%

Change-Id: I1bc501506a9f2f06071c5274391f6bd053b235a7