Revised adjustment for rd based on source complexity.
Two cases:

1) Bias against low variance intra predictors
when the actual source variance is higher.

2) When the source variance is very low to give a slight
bias against predictors that might introduce false texture
or features.

The impact on metrics of this change across the test sets is
small and mixed.

derf -0.073%, -0.049%, -0.291%
std hd -0.093%, -0.1%, -0.557%
yt  +0.186%, +0.04%, - 0.074%
ythd +0.625%, + 0.563%, +0.584%

Medium to strong psycho-visual improvements in some
problem clips.

This feature and intra weight on GF group length now
turned on by default.

Change-Id: Idefc8b633a7b7bc56c42dbe19f6b2f872d73851e

This experiment biases the rd decision based on the impact
a mode decision has on the relative spatial complexity of the
reconstruction vs the source.

The aim is to better retain a semblance of texture even if it
is slightly misaligned / wrong, rather than use a simple rd
measure that tends to favor use of a flat predictor if a perfect
match can't be found.

This improves the appearance of texture and visual quality
on specific test clips but is hidden under a flag and currently
off by default pending visual quality testing on a wider Yt set.

Change-Id: Idf6e754a8949bf39ed9d314c6f2daaa20c888aad

Make the C and SSE2 versions consistent.

Change-Id: I03c405d22a36bd1a97480efb96dc5af230667424

Use force_split to constrain the partition selection.
This is used because in the top-down approach to variance partition,
a block size may be selected even though one of its subblocks may have
high variance.

In this patch the selection of the 64x64 block size will only
be allowed if the variance of all the 32x32 subblocks are also below the threshold.

Stil testing, but some visual improvement for areas near slow moving boundary
can be seen. Metrics for RTC set increase by about ~0.5%.

Change-Id: Iab3e7b19bf70f534236f7a43fd873895a2bb261d

Code refactoring.

Change-Id: I73b6fcc0444155ee46c1efa5253c1d608c6439cb

Change-Id: I5169155b20ea3676a6ce58ec77d6aeba07db29d9

Change-Id: I0ba02d501d65a2f219fa1bb87b8eb81f7e6ab332

The mvs are clamped in the vp9_find_best_ref_mvs() already.

Change-Id: I9bea5e35aef6007466fe7fca4bc2dc5c17e74222

Change-Id: I41ee684cf113a7b5edf280183e51cb08b2e93cc4

Reduce unnecessary fetch from MB_MODE_INFO.

Change-Id: Iff89b76d5e2774c00a564e902913a633fa2e1ea9

Change-Id: I10c1ad23b110cf92cb026e895039c215c47abfd0

* changes:
  usage.dox: fix encoder/decoder subpage list indent
  usage.dox: fix doxygen warnings in 1.8.x

Move the scaling factor outside column projection. This avoids
repeated calculation of the same scaling factor. Profiling shows
that the percentage of vp9_int_pro_col_sse2 of overall cycles
goes from 2.29% down to 1.88%.

Change-Id: I5ac4e324ab2d7f33ba2de66dd2a12e04e04dfd66

Change-Id: I4039f8ac75a9cfcc4d07abd0619d1379bb10fe51

1. remove duplicate initialization to mbmi->interp_filter.
2. move mv clamping into ref_frame loop instead of mode checking loop.
3. move the check if last frame is same as golden frame earlier to
avoid initialization of Golden reference related variables.

Change-Id: Idf2d05e19e94a24f69cc289687869fc71d2ff289

Change-Id: I32f0bcb40c6e7ba63bfae487739ededd0b6b2dde

use \li to separate the list items contained in conditionals. this
avoids the encode page becoming a sub-item of decode; likely a problem
in <1.8.3.
+ fix encoder conditional, spelling error
+ correct encode page name to match decode 'Encoding'

Change-Id: I67890f52bed8e708bad63fb8819a074e0beff2ca

use \li to denote list items with \if.

fixes the following likely visible in <1.8.3:
usage.dox: warning: Invalid list item found
usage.dox: warning: End of list marker found without any preceding list items

Change-Id: I33c72799edf9f8866596ac8f79247050b8c75681

The compression performance of speed -5 is on average 12.6% better
than speed -6. At lower bit-rates, the gains are typically 20% or
more. For 2-thread encoding, the speed -5 takes about 1.6x time of
speed -6.

Change-Id: If7a73464a24d33e8f49b9533b51ec51c8da7fc80

This makes clear that for end-usage, only 0 is supported currently.

Change-Id: I99795807c20df1d71b3c803e8d5f3b36583dcc85

The commit updates the comments in vp8cx.h to make it clear which
codec support each of codec control functions.

Change-Id: Ibf876e289d4325bbb61ce19311da60d384624c2f

Crash occured on very first key frame, because denoiser
temporal function was beng entered.

Updated denoiser unittest to set cpu_used from first frame,
and verified fix fixes the crash.

Change-Id: I3be1124b52846fbbe7248d2c3d6136e086c80bc1