Copy up to a certain bsize, otherwise set to a fixed bsize.
This helsp to reduce artifact near moving boundary caused by full partition
copy without checking motion of super-block.
This artifact can occur at speeds 3,4 in real-time mode.
Issue: https://code.google.com/p/webm/issues/detail?id=738.

Change-Id: I05812521fd38816a467f72eb6a951cae4c227931

Change-Id: I7b2b690d2d51d55daa642be4131e5febd78cbe0a

Change-Id: I75ad328c6d719df81cc24f3ae21c152af4ebdacc

Change-Id: I6371ef7301c6bc3138552bd349e9bd154dee3e08

This commit slightly increases the bit allocation for key frame. This
improves speed -5 coding performance by 2.77% with aq-mode=0 and by
2.78% with aq-mode=3.

Change-Id: Iaa3e777f80b9706306606af06e89852bac146659

Parameterize the frame level quantization index used in non-RD
coding flow with cbr.

Change-Id: I79cfbd9c32c0d0fc33ad720d2180432e910baf7a

This commit reduces the frequency of frames using finer quantizer
in non-RD coding flow, and slightly tune up the quantizer resolution
when used. It provides 1.7% compression gains in speed -5 at no speed
difference.

Change-Id: I430249a51260a841a0402666e5ec1566e4f7d5a6

The new tolerance is a little higher than before (especially
for kf/gf/arf) so this change gives an encode speed up
for some clips up for speeds 0-2.

Change-Id: I63f7d6c9cc11c7f58742f41e250dcd3eab1741eb

Change-Id: I434682bbd4cb2089cd213d77ed5a5e06256dc45d

This commit adjusted the speed steps in rt mode to make the steps
more evenly spaced on speed and quality, specifically:
1. Merged 3 and 4 into one single step 3 and removed confilicting
features.
2. Move 8, 7, 6, 5 to be 7, 6, 5, 4 repsectively.

Change-Id: I38d56d61531f3561d772aef953c411c8fb38c063

Change-Id: I7d9874da8ff78a2d7e0cf11073af9c30538bc9a6