this commit makes the usage errorperbit and sadperbit consistent for
encoding modes and passes. Removed all different magic weight factors
associated with errorperbit. Now 1/2 is used for both sadperbit16 and
sadperbit4, the /2 operation is merged into initializations of the 2
variables.

Tests on cif set show .23%, 0.18% and 0.19% gain by avg psnr, overall
psnr and ssim respectively.

Change-Id: Ifa285c3e065ce0a5a77addfc9f95aabf54ee270d

sad_per_bit has been used for a number of motion vector search routines
with different magic weights: 1, 1/2 and 1/4. This commit remove these
magic numbers and use 1/2 for all motion search routines, also reformat
a number of source code lines to within 80 column limit.

Test on cif set shows overall effect is neutral on all metrics. <=0.01%

Change-Id: I8a382821fa4cffc9c0acf8e8431435a03df74885

Small code cleanups before attempting to reduce the size
of bmi found in BLOCKD.

Change-Id: Ie9c14adb53afd847716a75bcce067d0e6c04f225

Misplaced #endif caused first_time_stamp_ever to only be initialized if
CONFIG_INTERNAL_STATS was set.

Change-Id: I2296a4ab00f7dfb767583edcc5d59b94f48c0621

in onyx_if.c update_reference_frames() make
sure that frame buffer indexes are not equal
before preforming a buffer copy.  If two frames
share the same buffer the flags will already be
set correctly.

Change-Id: Ida9b5516d08e3435c90f131d2dc19d842cfb536e

Test showed using hex search in realtime mode largely speed up
encoding process, and still achieves similar quality like the
diamond search we have. Therefore, removed the diamond search
option.

Change-Id: I975767d0ec0539f9f6ed7fdfc09506e39761b66c

Hex search is not called in rdopt.c

Change-Id: I67347f03e13684147a7c77fb9e9147e440bb5e8e

This patch fixes the compiler errors and the seg fault
when running decode_with_partial_drops.

Change-Id: I7c75369e2fef81d53b790d5dabc327218216838b

error_per_bit and sad_per_bit were designed as estimates of a bit worth
of sum squared error and sum absolute difference respectively. Under
this assumption, error_per_bit should be used in combination with 2nd
order errors (variance or sum squared error) while sad_per_bit should
be used in combination with 1st order SADs in motion estimation. There
were a few places where sad_per_bit has been misused with variances,
this commit changes to use error_per_bit for those places, also changes
parameter names to properly indicate which constant is being used.

On cif set, the change has a universal gain by all metrics: 0.13% by
average/overall psnr and 0.1% by ssim.

Change-Id: I4850fdcc3fd6886b30f784bd843f13dd401215fb

Change-Id: I6e5e86235d341cce3b02abda26dbeb71940ed955

Minor modification.

Change-Id: I09511d38fd1451d5c4106a48acdb3f766ce59cb7

  'sum' returned by get8x8var is not used and var8x8 has optimizations
  for more platforms.

Change-Id: I4a907fb1a05f285669fb0b95dc71d42182c980f6

While profile=3, there is no sub-pixel search. Distortion and SSE
have to calculated using get_inter_mbpred_error().

Change-Id: Ifb36e17eef7750af93efa7d0e2870142ef540184

Less operations.

Change-Id: Ibb9cd5ae66b8c7c681c9a654d551c8729c31c3ae

Change-Id: I6e5e921f03dc15a72da89a457848d519647677a3

Declared the bmi in MODE_INFO as a union instead of B_MODE_INFO.
This reduced the memory footprint by 518,400 bytes for 1080
resolutions.  The decoder performance improved by ~4% for the
clip used and the encoder showed very small improvements. (0.5%)
This reduction was first mentioned to me by John K. and in a
later discussion by Yaowu.
This is WIP.

Change-Id: I8e175fdbc46d28c35277302a04bee4540efc8d29

In vp8dx_set_reference, the new reference image is written to an
unused reference frame buffer.

Change-Id: I9e4f2cef5a011094bb7ce7b2719cbfe096a773e8

Reduced some bound checks in hex search function.

Change-Id: Ie5f73a6c227590341c960a74dc508cff80f8aa06

VP8_UVSSE mistakenly used subpixvar8x8 to calculate SSE for non-subpixl
motion cases.

Change-Id: I4a5398bb9ef39c211039f6af4540546d4972e6a9

Change-Id: Ia96e5bf915e4d3c0ac9c1795114bd9e5dd07327a