tree 3aaa3d9c56c6fd5ae996b964645e371236adebbb
parent fa73e201d8d79749710ecf84fed92d3228905c32
author Yunqing Wang <yunqingwang@google.com> 1566232091 -0700
committer Yunqing Wang <yunqingwang@google.com> 1566451393 +0000

Prune tx type search using previous stats

Record tx type usage and using the stats to prune following frame's
tx type search. Borg test result for speed 4:
         avg_psnr:   ovr_psnr:   ssim:
midres:   0.120        0.107    -0.034
Average speedup over whole midres set is 3.2%.
Will work on extending this feature to other speeds.

Change-Id: I864e1e4515c0f707aa48a3c0f9ed67b573603739