One is a more aggressive version of the pruned subpel tree
search where only a single halfpel candidate is searched.
The search candidate is based on a surface fit result.
The other is a method to obtain the subpel position at one
shot based on the same surface fit.

The methods have not been deployed in any speed setting yet.

Change-Id: I34fef3f2e34f11396c9d1ba97f4be8c4ffca62d3

This patch re-enabled the feature in Pengchong's patch
(commit 12861260). Originally, it
was turned on while use_lastframe_partitioning > 0(not used anymore).
Now it was added as a feature, and turned on while speed >= 2.
As described in the original patch, this feature helps speed up the
slideshows in YouTube.

Change-Id: I1b0f18d65da1ee1c8d1e117dabba910c5207c471

This commit enables an adaptive mode search order scheduling scheme
in the rate-distortion optimization. It changes the compression
performance by -0.433% and -0.420% for derf and stdhd respectively.
It provides speed improvement for speed 3:

bus CIF 1000 kbps
24590 b/f, 35.513 dB, 7864 ms ->
24696 b/f, 35.491 dB, 7408 ms (6% speed-up)

stockholm 720p 1000 kbps
8983 b/f, 35.078 dB, 65698 ms ->
8962 b/f, 35.054 dB, 60298 ms (8%)

old_town_cross 720p 1000 kbps
11804 b/f, 35.666 dB, 62492 ms ->
11778 b/f, 35.609 dB, 56040 ms (10%)

blue_sky 1080p 1500 kbps
57173 b/f, 36.179 dB, 77879 ms ->
57199 b/f, 36.131 dB, 69821 ms (10%)

pedestrian_area 1080p 2000 kbps
74241 b/f, 41.105 dB, 144031 ms ->
74271 b/f, 41.091 dB, 133614 ms (8%)

Change-Id: Iaad28cbc99399030fc5f9951eb5aa7fa633f320e

The speed feature that skips compound inter prediction modes was
subsumed by other speed features and effectively was not in use.
This commit removes it.

Change-Id: I22b0c71a8ddd15d93b25d86fa63a1dce2ba6a1a9

This commit refactor the rate-distortion optimization search for
regular block sizes to remove the speed feature dependency on mode
search order.

Change-Id: Ied033ee484c2957e17baa7b6450b720fe7dd0e7d

This commit allows encoder to skip intra coding mode test, when
the known inter residual is less than the source variance. It
reduces the runtime of speed 3 for test clips:
bus cif 1000 kbps: 8587 ms -> 8260 ms, 3.8% speed-up
pedestrian 1080p 2000 kbps: 161381 ms -> 155241 ms, 3.7% speed-up.

The compression performance is down by
derf   -0.36%
stdhd  -0.25%

Change-Id: I75ce1e035b4da2153cb1ac14111d1a07c05a735d

In the partition search, the encoder checks all possible
partitionings in the superblock's partition search tree.
This patch proposed a set of criteria for partition search
early termination, which effectively decided whether or
not to terminate the search in current branch based on the
"skippable" result of the quantized transform coefficients.
The "skippable" information was gathered during the
partition mode search, and no overhead calculations were
introduced.

This patch gives significant encoding speed gains without
sacrificing the quality.

Borg test results:
1. At speed 1,
   stdhd set: psnr: +0.074%, ssim: +0.093%;
   derf set:  psnr: -0.024%, ssim: +0.011%;
2. At speed 2,
   stdhd set: psnr: +0.033%, ssim: +0.100%;
   derf set:  psnr: -0.062%, ssim: +0.003%;
3. At speed 3,
   stdhd set: psnr: +0.060%, ssim: +0.190%;
   derf set:  psnr: -0.064%, ssim: -0.002%;
4. At speed 4,
   stdhd set: psnr: +0.070%, ssim: +0.143%;
   derf set:  psnr: -0.104%, ssim: +0.039%;

The speedup ranges from several percent to 60+%.
                 speed1    speed2    speed3    speed4
(1080p, 100f):
old_town_cross:  48.2%     23.9%     20.8%     16.5%
park_joy:        11.4%     17.8%     29.4%     18.2%
pedestrian_area: 10.7%      4.0%      4.2%      2.4%
(720p, 200f):
mobcal:          68.1%     36.3%     34.4%     17.7%
parkrun:         15.8%     24.2%     37.1%     16.8%
shields:         45.1%     32.8%     30.1%      9.6%
(cif, 300f)
bus:              3.7%     10.4%     14.0%      7.9%
deadline:        13.6%     14.8%     12.6%     10.9%
mobile:           5.3%     11.5%     14.7%     10.7%

Change-Id: I246c38fb952ad762ce5e365711235b605f470a66

Updates the vp9_pattern_search function to return integer one-away
neighbors' sad values, for subsequent use in speeding up the
sub-pel search. Also, removes code for the do_refine option
which is not being used currently.
Updates the integer and subpel functions to pass in a 5-element
sad list for output or input.

A new pruned sub-pel search algorithm is implemented that uses
the sad returned from the integer pel search. But it is not
deployed yet.

Change-Id: Ifa9f5ad024b5b660570366d2bd900343e1891520

This commit addes a new strategy to reduce the search for optimal
interpolation filter type. The encoder counts and store how many each
filter type is selected and used for each of the reference frames.
A filter type that is rarely used for all three reference frames is
masked out to avoid computation.

The impact on compression is neglectible:
-0.02% on derf
+0.02% on stdhd

Encoding time is seen to reduce by 2~3%.

Change-Id: Ibafa92291b51185de40da513716222db4b230383

In the full-rd transform size search, we go through all transform
sizes to choose the one with best rd score. In this patch, an
early termination is added to stop the search once we see that the
smaller size won't give better rd score than the larger size. Also,
the search starts from largest transform size, then goes down to
smallest size.

A speed feature tx_size_search_breakout is added, which is turned off
at speed 0, and on for other speeds. The transform size search is
turned on at speed 1.

Borg test results:
1. At speed 1,
   derf set: psnr gain: 0.618%, ssim gain: 0.377%;
   stdhd set: psnr gain: 0.594%, ssim gain: 0.162%;
   No noticeable speed change.
3. At speed 2,
   derf set: psnr loss: 0.157%, ssim loss: 0.175%;
   stdhd set: psnr loss: 0.090%, ssim loss: 0.101%;
   speed gain: ~4%.

Change-Id: I22535cd2017b5e54f2a62bb6a38231aea4268b3f

This commit enables the encoder to record the location of the
center frame to generate alter reference frame. It then allows to
skip checking prediction modes of other reference frame types when
it comes to encode this frame.

The speed 3 runtime is reduced for the test sequences:
bus at CIF 1000 kbps, 9791 ms -> 9446 ms, i.e., 3.5% speed-up,
pedestrian at 1080p 2000 kbps, 184043 ms -> 175730 ms, i.e., 4.5%
speed-up.

No compression performance change observed.

Change-Id: Iacfde3bcc1445964e7a241f239bd6ea11cb94bd1

Add a speed feature to give the tighter partition search
range. Before partition search, calculate the histogram
of the partition sizes of the left, above and previous
co-located blocks of the current block. If the variance of
observed partition sizes is small enough, adjust the search
range around the mean partition size, which will be tigher.

The feature is currently turned on at speed 2. Experiments on
sample youtube clips show on average the runtime is reduced
by 3-7%.

For hard stdhd clips:
park_joy_1080p @ 15000kbps:       509251 ms -> 491953 ms (3.3%)
pedestrian_area_1080p @ 2000kbps: 223941 ms -> 214226 ms (4.3%)

The PSNR performance is changed:
derf: -0.112%
yt:   -0.099%
hd:   -0.090%
stdhd:-0.102%

Change-Id: Ie205ec5325bf92ec5676c243e30ba9d0adca10f2

Removed disable_split_var_thresh, which is not used anymore.

Change-Id: I50119b150442e1571157433b5effc6aae0dbe0fd

This commit allows the encoder to check the above and left neighbor
blocks' reference frames and motion vectors. If they are all
consistent, skip checking the NEARMV and ZEROMV modes. This is
enabled in speed 3. The coding performance is improved:

pedestrian area 1080p at 2000 kbps,
from  74773 b/f, 41.101 dB, 198064 ms
to    74795 b/f, 41.099 dB, 193078 ms

park joy 1080p at 15000 kbps,
from 290727 b/f, 30.640 dB, 609113 ms
to   290558 b/f, 30.630 dB, 592815 ms

Overall compression performance of speed 3 is changed
derf  -0.171%
stdhd -0.168%

Change-Id: I8d47dd543a5f90d7a1c583f74035b926b6704b95

This commit enables a chessboard pattern constrained partition
search for 720p and above resolutions. The scheme applies stricter
partition search to alternative blocks based on its above/left
neighboring blocks' partition range, as well as that of the
collocated blocks in the previous frame. It is currently turned
on at 16x16 block size level. The chessboard pattern is flipped
per coding frame.

The speed 3 runtime is reduced:
park_joy_1080p, 652832 ms -> 607738 ms (7% speed-up)
pedestrian_area_1080p, 215998 ms -> 200589 ms (8% speed-up)

The compression performance is changed:
hd     -0.223%
stdhd  -0.295%

Change-Id: I2d4d123ae89f7171562f618febb4d81789575b19

This commit enables a chessboard pattern prediction filter type
search scheme for rate-distortion optimization speed-up. For the
inferred motion vector modes, the encoder can re-use its above/left
neighbor blocks' prediction filter type and skip a full test on
all possible filter types. Such operation is turned on/off
alternatively in a chessboard manner.

It is turned on in speed 3. For test clip pedestrian 1080p, the
runtime is reduced from 231500 ms -> 221700 ms. The compression
performance is changed:
derf:  -0.147%
yt:    -0.134%
hd:    -0.079%
stdhd: -0.220%

Change-Id: I1912f278e7576c2dc632688e3ad7a257410c605a

This commit changed the hard-coded DEFAULT_INTERP_FILTER to a speed
feature with the same default value: SWITCHABLE.

Change-Id: I7f54f40f1bd3f5277841d04b85db7a84e47313f1

* Replace max_step_search_steps with constant MAX_MVSEARCH_STEPS
* Fold (reduce_first_step_size + speed > 5) into reduce_first_step_size
  replacing uses of reduce_first_step_size that don't add the speed
  check with zero.

Change-Id: Iae46395dbf3eaca138bf4d18b838a9e364b5a198

This commit added a speed feature to control the step_param used in
full pixel motion search. The intention is to reduced the search
steps for high speed real time coding.

Change-Id: I21d2f0105c2b647783a6688615da7fcf2b6d670b

This commit re-designs the quantization process for transform
coefficient blocks of size 4x4 to 16x16. It improves compression
performance for speed 7 by 3.85%. The SSSE3 version for the
new quantization process is included.

The average runtime of the 8x8 block quantization is reduced
from 285 cycles -> 255 cycles, i.e., over 10% faster.

Change-Id: I61278aa02efc70599b962d3314671db5b0446a50

The current threshold is knid of low, and in many cases NEWMV
mode is checked but not picked as the best mode. This patch
added a speed feature to increase NEWMV threshold, so that
less partition mode checking goes to check NEWMV. This feature
is enabled for speed 6 and 7.

Rtc set borg tests showed:
1. Speed 6, overall psnr: -0.088%, ssim: -1.339%;
   Average speedup on rtc set is 11.1%.
2. Speed 7, overall psnr: -0.505%, ssim: -2.320%
   Average speedup on rtc set is 12.9%.

Change-Id: I953b849eeb6e0d5a1f13eacba30c14204472c5be

For real time speed 7, once encode breakout is on(i.e. encoding
setting --static-thresh=1), a proper encode breakout threshold
is set to speed up the encoder.

Set --static-thresh=1, RTC set borg test showed a slight overall
psnr loss of 0.162%, but ssim gain of 0.287%. The average speedup
on RTC set is 6%, and for some clips, the speedup can be 10+%.

Change-Id: Id522d9ce779ff7c699936d13d0c47083de4afb85

Before encoding a frame, calculate and store each 16x16 block's
variance of source difference between last and current frame.
Find partitioning threshold T for the frame from its variance
histogram, and then use T to make partition decisions.

Comparing with fixed 16x16 partitioning, rtc set test showed an
overall psnr gain of 3.242%, and ssim gain of 3.751%. The best
psnr gain is 8.653%.

The overall encoding speed didn't change much. It got faster for
some clips(for example, 12% speedup for vidyo1), and a little
slower for others.

Also, a minor modification was made in datarate unit test.

Change-Id: Ie290743aa3814e83607b93831b667a2a49d0932c

As a way to speed-up rtc encoding at speed 7.

Change-Id: Ie36a010392cf7b741dc130df21a4e733622a75b7

In real-time speed 6, no partition search is done. The inter
prediction results got from picking mode can be reused in the
following encoding process. A speed feature reuse_inter_pred_sby
is added to only enable the resue in speed 6.

This patch doesn't change encoding result. RTC set tests showed
that the encoding speed gain is 2% - 5%.

Change-Id: I3884780f64ef95dd8be10562926542528713b92c

Fix some bugs relating to the use of buffers
in the overlay frames.

Fix bug where a mid sequence overlay was
propagating large partition and transform sizes into
the subsequent frame because of :-
  sf->last_partitioning_redo_frequency  > 1 and
  sf->tx_size_search_method == USE_LARGESTALL

Change-Id: Ibf9ef39a5a5150f8cbdd2c9275abb0316c67873a

Moving all motion vector related speed parameters from SPEED_FEATURES to
MV_SPEED_FEATURES.

Change-Id: I3e9af0039c7162f8671878c5920bce3cb256a84e

Change-Id: I33a38bb9f46e7ef509bbbf0cfd7bc3ea5072d022

In non-rd real-time mode, choosing smaller transform size in
encoding gives better video quality and good speed gain than
choosing larger transform size. This patch set tx size search
method to ALLOW_8X8, which is better than using 4x4 or other
larger sizes.

Borg tests on rtc set at speed 6 showed significant gain on quality.
PSNR gain: 11.034% and SSIM gain: 15.466%.

The speed gain is 5% - 12% for <720p clips, and 2% - 7% for
720p clips.

Change-Id: If4dc74ed2df359346b059f47fb73b4a0193ec548

This is not a speed feature, adding inline function instead.

Change-Id: Ia48c41802eec9e92cf990339d724097279695c9a

Making this consistent with intra mode masks: you need to specify
allowed inter/intra modes to use.

Change-Id: Iaecd28bf79047259707d8e7a59a57bb7b856383e

This commit changed to enable the encoder to adjust motion dection
speed threshold based on picture size. In addition, cpu-used 1 now
does a partition search every other frame instead of every third
frame for low resolution inputs.

The change has no quality/speed impact for 720p and above. Test
showed the change increase encoding time by between 3% to 6% for
cpu-used 2 encodiong of 360p sequences. It also has a compression
gain about .3%.

For cpu-used 2, the change resolved some very disturbing visual
artifacts in certain sequences when large block partitionings and
transforms are used as a result of copying the partition from a
previous frame.

Change-Id: Ic7fd22508cdb811d4ca935655adbf20109286cfa

Added a skipping test in non-rd inter-mode. After interpolation
prediction step, the residuals are tested to see if they will be
quantized to 0 based on modeling between spatial domain and
frequency domain.

Set static-thresh to 800 for >=720p and 300 for <720p, rtc set
tests showed
1. Speed 5, psnr: -0.514%; ssim: -1.748%;
   speedup on related clips: 5% -11%
2. Speed 6, psbr: -0.628%; ssim: -1.637%;
   speedup on related clips: 4% - 9%

Change-Id: I62fbf26bc043ecd2b584f255f1a4ee5ab52bfcf3

Change-Id: If1afb9f3eaec88079d1d97907870409bce691c2a

Change-Id: I961d50d6fafdd37ef7f23f0a871d28e28d2084ca

This commit introduces a chessboard pattern search for the prediction
filter type search. It runs extensive search in alternate blocks and
allows the rest blocks to refer coding decisions of their nearby
neighbors.

For pedestrian 1080p at 4000 kbps, the runtime of speed -5 goes down
from 43990 ms to 42200 ms. The overall compression performance for
RTC set is changed by -1.37%.

Change-Id: Icfe220c49451cda796f0ca91d935c9ed01e56c9d

Minor change to use matching type in comparison.

Change-Id: I670cae2d584918c67c1af791a797629f392f599e

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

Copy up to a certain bsize, otherwise set to a fixed bsize.
This helsp to reduce artifact near moving boundary caused by full partition
copy without checking motion of super-block.
This artifact can occur at speeds 3,4 in real-time mode.
Issue: https://code.google.com/p/webm/issues/detail?id=738.

Change-Id: I05812521fd38816a467f72eb6a951cae4c227931

Change-Id: I75ad328c6d719df81cc24f3ae21c152af4ebdacc