ref: 9d41313e4bd28d3c504c26079cbe4a499e7eceb7
parent: a93c506034710a21a0a93a71fff71b794f3f9579
author: Yunqing Wang <yunqingwang@google.com>
date: Thu May 1 11:14:39 EDT 2014
Decide the partitioning threshold from the variance histogram Before encoding a frame, calculate and store each 16x16 block's variance of source difference between last and current frame. Find partitioning threshold T for the frame from its variance histogram, and then use T to make partition decisions. Comparing with fixed 16x16 partitioning, rtc set test showed an overall psnr gain of 3.242%, and ssim gain of 3.751%. The best psnr gain is 8.653%. The overall encoding speed didn't change much. It got faster for some clips(for example, 12% speedup for vidyo1), and a little slower for others. Also, a minor modification was made in datarate unit test. Change-Id: Ie290743aa3814e83607b93831b667a2a49d0932c