This fixes warning when compiling libvpx for PNaCl. PNaCl's version
of math.h defines M_LOG2_E.

Change-Id: Iba9450441538e9f82447ad2936bea94d21bafdf1

This reverts commit 22a3e307

Change-Id: I460d905edf5fb2006da58c18fbe02c04d0c631bb

Change-Id: I0462bf1ca1b4e5a1c06259979b4daff949b8a2c6

Change-Id: I1324c339815a47004ddccdaf651d24c60382b92f

Cleanup.

Change-Id: I54d989e24b35323cda7290654e425565d5c9ea2d

Change-Id: I721ff26e3d5dbef80b8cd2dd562adae3748f6687

Change-Id: I9be2e4e9aeda0fae6dc946deae2999be51daebe0

In mode selection loop, once mode_index pass mode_skip_start, all
modes with a different reference frame from current best mode are
masked out using mode_skip_mask.

However, the setting of mode_skip_mask may use an invalid mode if
there is no mode tested yet. This commit fixes the issue by making
sure a mode has been tested and selected. Otherwise, no mode will be
masked out because of their reference frame.

Change-Id: Ib0009e8a96836a65cf5347440fff8a2e1a67f29f

Change-Id: I9b8f9a3f4fa9d48695149dd68ecb5e8d84accafe

Change-Id: Idf612c772440158cd1645623241c51ab0d57405c

Change-Id: I7a5230852cb24ce22bfe85ea2608cdb4619b5200

Change-Id: I08fe184a04e5435aeac92f1d7cc9733ca52c2783

Change-Id: Ib64edeb58b3e25488fb85bbe85c9decb15b4d0a1

The macosx release of clang v5.0 identifies itself as:
Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)

This version of clang uses the older _mm_broadcastsi128_si256, like
v3.3, as given away in the LLVM svn version above.

Change-Id: I4d6d59d5454efd57d2ae9e75f5eb7486af7cbd0c

Change-Id: I3ced24f2c3b9cc483278c0f0d60512e7d2efa4f4

Calculate the difference variance between last source frame and
current source frame. The variance is calculated at 16x16 block
level. The variances are compared to several thresholds to decide
final partition sizes.

An adaptive strategy is implemented to decide using
SOURCE_VAR_BASED_PARTITION or FIXED_PARTITION based on motions
in the video. The switching test is done once every
search_type_check_frequency frames.

The selection of source_var_thresh needs to be investigated
further later.

RTC set Borg test showed 0.424% overall psnr gain, and 0.357%
ssim gain. For clips with large enough static area, the
encoding speedup is around 2% to 15%.

Change-Id: Id7d268f1d8cbca7fb8026aa4a53b3c77459dc156

This commit allows the non-RD mode decision flow to  select
prediction filter type in NEWMV mode. It provides 8.14% compression
performance gains in both settings of AQ=0 and 3. The current speed
impact is about 5% to 10% slower.

Change-Id: Id66ecebf77abd8f90fb3f6a066c0e8dfb4bf1c42