While investigating the effect of DC values on SAD and SSE in motion
estimation, a side finding indicates the two table of constants need
be adjusted. The adjustment was done by multiplying old constants by
90% with rounding. Also absorb the 1/2 scaling constant into the two
tables. Refer to change Ifa285c3e for background of the 1/2 factor.

Cif set test showed a very small gain on all metric.

Change-Id: I04333527a823371175dd46cb04a817e5b9a8b752

Change-Id: I5b0aaca06f2e0f40588cb24fb0642b6865da8970

Change-Id: Id66e70540ee7345876f099139887c1843093907f

In real-time mode motion search, there is no need to calculate
variance. This change improved encoding speed by 1% ~ 2%(speed=-5).

Change-Id: I65b874901eb599ac38fe8cf9cad898c14138d431

Fixes #326

Change-Id: I5f2a4257430ef62f674190acefd43a0474821288

This patch attempts to reduce the peak bitrate hit by the encoder
when using small buffer windows.

Tested on the CIF set over 200-500kbps using these settings:

  --buf-sz=500 --buf-initial-sz=250 --buf-optimal-sz=250 \
  --undershoot-pct=100

Two pass encodes were tested at best quality. One pass encodes were
tested only at realtime speed 4:

  --rt --cpu-used=-4

The peak datarate (over the specified 500ms window) was measured
for each encode, and averaged together to get metric for
"average peak," computed as SUM(peak)/SUM(target). This patch
reduces the average peak datarate as follows:

  One pass:
    baseline:   1.29715
    this patch: 1.23664

  Two pass:
    baseline:   1.32702
    this patch: 1.37824

This change had a positive effect on our quality metrics as well:

  One pass CBR:
                    Min  / Mean / Max (pct)
    Average PSNR    -0.42 / 2.86 / 27.32
    Overall PSNR    -0.90 / 2.00 / 17.27
    SSIM            -0.05 / 3.95 / 37.46

  Two pass CBR:
                    Min  / Mean / Max (pct)
    Average PSNR    -4.47 / 4.35 / 35.99
    Overall PSNR    -3.40 / 4.18 / 36.46
    SSIM            -4.56 / 6.98 / 53.67

  One pass VBR:
                    Min  / Mean / Max (pct)
    Average PSNR    -5.21 /  0.01 / 3.30
    Overall PSNR    -8.10 / -0.38 / 1.21
    SSIM            -7.38 / -0.11 / 3.17
    (note: most values here were close to the mean, there were a few
     outliers on files that were very sensitive to golden frame size)

  Two pass VBR:
                    Min  / Mean / Max (pct)
    Average PSNR    0.00 / 0.00 / 0.00
    Overall PSNR    0.00 / 0.00 / 0.00
    SSIM            0.00 / 0.00 / 0.00

Neither one pass or two pass CBR mode adheres particularly strictly
to the short term buffer constraints, and two pass is less
consistent, even in the baseline commit. This should be addressed
in a later commit. This likely will hurt the quality numbers, as it
will have to reduce the burstiness of golden frames.

Aside: My work on this commit makes it clear that we need to make
rate control modes "pluggable", where you can easily write a new
one or work on one in isolation.

Change-Id: I1ea9a48f2beedd59891f1288aabf7064956b4716

left_block_mv and above_block_mv will return the MB
motion vector for non SPLITMV macro blocks.

Change-Id: I58dbd7833b4fdcd44b6b72e98ec732c93c2ce4f4

Currently, hex search couldn't guarantee the motion vector(MV)
found is within the limit of maximum MV. Therefore, very large
motion vectors resulted from big motion in the video could cause
encoding artifacts. This change adjusted hex search bounds
checking to make sure the resulted motion vector won't go out
of the range. James Berry, thank you for finding the bug.

Change-Id: If2c55edd9019e72444ad9b4b8688969eef610c55

Declared the bmi in BLOCKD as a union instead of B_MODE_INFO.
Then removed B_MODE_INFO completely.

Change-Id: Ieb7469899e265892c66f7aeac87b7f2bf38e7a67

This is basically a slightly modified version of the previous patch,
and it has a moderately positive effect (SSIM/PSNR both +0.08% avg
on derf-set). Most clips show no change, except waterfall/coastguard,
each ~ +0.8% SSIM/PSNR. You can see similar effects in other clips
by shortening their length to terminate at a very short last group
of frames.

Change-Id: I7a70de99ca1f9fe6a8b6ca7a6e30e8a4b64383e4

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

The fb_idx_ref_cnt book-keeping was in error. Added an assert to
prevent future errors in the reference count vector. Also fixed a
pointer syntax error.

Change-Id: I563081090c78702d82199e407df4ecc93da6f349

Change-Id: Iccbd78d91c3071b16fb3b2911523a22092652ecd

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

vp8_fast_quantize_b_pair_neon function added to quantize
two adjacent blocks at the same time to improve performance.
 - Additional 3-6% speedup compared to neon optimized fast
   quantizer (Tanya VGA@30fps, 1Mbps stream, cpu-used=-5..-16)

Change-Id: I3fcbf141e5d05e9118c38ca37310458afbabaa4e

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

Added preload instructions to armv6 encoder optimizations.
About 5% average speed-up on Tegra2 for VGA@30fps sequence.

Change-Id: I41d74737720fb71ce7a316f07555357822f3347e

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