tree 2b41594071a53fcff3e2ba470ec6b45f3231a8f8
parent fd2c0cf8fd10a0b95ba93be98943e7504dd534c7
author Cheng Chen <chengchen@google.com> 1607026424 -0800
committer Cheng Chen <chengchen@google.com> 1607041052 -0800

Use 8x8 block size for screen content in the first pass

Screen content videos often contain details, for example characters,
and sharp changes in a small neighborhood.

With smaller block sizes, the motion estimation allows the first pass
to get a better estimation of coded errors, thus helping the encoding
decisions in the second pass.

With this change, for screen content test set, on speed 1, 150 frame,
we can see -1.5% gain on psnr, -0.4% ssim, -1.3% vmaf.

Other test sets still use 16x16 block sizes.

STATS_CHANGED

Change-Id: I3d51320b56adc8ae8bf342a1af7053770a5df198