ref: 5a3e3c6d3fa308066e2cef1f8cbc407cd540c176
parent: 73eeb3beffefb5238071988fbea94cba9c2b558b
author: Jingning Han <jingning@google.com>
date: Wed Jun 25 12:53:07 EDT 2014
Adaptive txfm size selection depending on residual sse/variance This commit enables an adaptive transform size selection method for speed -6. It uses largest transform size when the sse is more than 4 times of variance, i.e., most energy is compacted in the DC coefficient. Otherwise, use the default TX_8X8. It improves the compression efficiency for rtc set of speed -6 by 0.8%, no speed change observed. Change-Id: Ie6ed1e728ff7bf88ebe940a60811361cdd19969c