commit 25ca32295772f84f91ec73c77fc78784ddb9a15a
author Jingning Han <jingning@google.com> Tue Jun 07 17:54:20 2016 -0700
committer Jingning Han <jingning@google.com> Fri Jun 10 12:56:14 2016 -0700
tree 41d7202e61cecc7563d00f885362a005a3516e8c
parent e14f61b9242eca30071a19d53dfad9ade6515099

Trellis based adaptive quantization

This commit combines uniform quantizer with trellis based coefficient
level optimization. It improves the codebase compression performance:

lowres 0.8%
midres 1.0%
hdres  1.6%

Note that the current trellis optimization unit is using C code. This
will make the cost of the overall quantization process slower. A number
of optimizations will come up next.

Change-Id: Id441dd238e4844409d0f08f82604be777f3f5282