The intra mode distortion adjustment for skip_encode feature was
broken in the refactoring cc91851. This commit fixes it and tunes
the distortion models used therein.

Change-Id: I0d676e82f8e855536a90cf9b3e3fdefafcd886c6

snprintf is not supported by MSVC, the commit replace it with the msvc
variant _snprintf to enable build.

Change-Id: I686943a78c289bae6b486a5e75effad5f86c24de

Some minor cleanups in preparation for experimentation with
some encode parameters and thresholds

Change-Id: I449d66da97eae0a7acdf4aae374e2f9111342056

Use b_mode_info to store the inter prediction mode of sub8x8 block,
in replacement of the use of partition_info. Remove redundant buffer
update for partition_info. For bus_cif at 2000 kbps, this seem to make
speed 0 about 1% faster.

Change-Id: Id1b3be45e75a24fb4b42335ac480c23e440978f6

Change-Id: Ic31b4ef85e65070b4f8b9f26e068ccfaae00c4f0

Change-Id: Id1fde9920d60c6991a8ef6de5103ae3e578312ed

When all coefficients are zeros, skip the corresponding 1-D inverse
transform. This practice has been used in the SSE2 implementation of
inverse 32x32 DCT. This commit imports this algorithm into the C code.

Change-Id: I0f58bfcb183a569fab85d524d5d9cf8ae8653f86

For CpuUsed 1 & 2, this commit allow to skip retangular partition check
when NONE is better than SPLIT. It also changed to allow such logic
on alt ref frame coding rather than use square partition all them. The
change has gain compressio about .3% on yt and ythd for both 1&2, It
helped .6% compression on cif and stdhd for both CpuUsed 1&2.

Change-Id: I814b653baf89f59acd20e042629a12938a1bd4e5

Change-Id: Id093816146de0d100f0c6ae2542aaa427dbab2d8

Change-Id: I38b2100f1a64cb067c63f4e1662c36914b3569df

Change-Id: Ia725748acbc2a3f825f0d208f26522a0412301fa

Adjusts the bits per mb parameter about 10% smaller.

Results at speed 0:
fullderfraw: +0.255%
fullstdhdraw: +0.262%
stdhdraw250: +0.291%

Change-Id: I2b7317ac3f61737bc77eb5470aad870cade83fa5

Declaring vp9_pt_energy_class in vp9_entropy.h instead of many external
places.

Change-Id: I66e8a3fc119a43f88d130d0dae4133c825a047a3

Slightly bigger change -> broke up encode_frame_to_datarate,  lots
of line length fixes.

Change-Id: I7c53325e954de130f3fe1a6656626efc6705be82

Change-Id: I8de865cd1deca07b5c92c225782f0867367e9a11

Change-Id: Iae7674b0c946a5ac01617840b3f62965c654d920

This flag is for stats generation and testing and should not
be checked in as enabled by default.

Change-Id: I4ea57dbcf49790f14777f598ddd3dc37dcc7a6bb

as the name implies, the segmentation pointer can be const

Change-Id: I945f01a077c112ec86c00e35a1e9395bc230c2d9

A new set of MSVC warnings were introduced by change
I3f36d3f7cd8d15195a6e2fafd1777cdaf9ecb847

In particular MSVC does not like:-

typedef const int16_t subpel_kernel[SUBPEL_TAPS];

struct subpix_fn_table {
  const subpel_kernel *filter_x;
  const subpel_kernel *filter_y;
};

causes  new warning in MSVC.
warning C4114: same type qualifier used more than once

Change-Id: Iae596fd13aadf36169faf00c68eabe9a32a9b156