tree c4e85f04e1a61db72e9e2135de61e404b2f38a32
parent fc83791043ba681cab6402e0a337722a95d9bcf1
author Debargha Mukherjee <debargha@google.com> 1535249018 -0700
committer Debargha Mukherjee <debargha@google.com> 1535406548 +0000

Change the key-frame q mapping function

Increases the quality of key frames, but also reduces the
kf boost more when the key frame interval is small.

Results generally improve for SSIM, a little drop in
PSNR at short key frame intervals for low resolution videos.
However, visual quality shows a bigger improvement for several
YT encodes.

Results:
========
[lowres, cpu_used=1, 30 frames]:
Av PSNR 0.225%,	SSIM -0.570%

[lowres, cpu_used=1, 60 frames]:
Av PSNR 0.073%,	SSIM -0.575%

[midres, cpu_used=1, 30 frames]:
Av PSNR -0.023%, SSIM -0.314%

[midres, cpu_used=1, 60 frames]:
Av PSNR -0.348%, SSIM -0.582%

STATS_CHANGED

Change-Id: I729891693b4b0cfe9582e622de77bb546f981610