The existing test was triggering a lot of false positives on some types
of animated material with very plain backgrounds. These were triggering
code designed to catch key frames in letter box format clips.

This patch tightens up the criteria and imposes a minimum requirement
on the % blocks coded intra in the first pass and the ratio between the
% coded intra and the modified inter % after discounting neutral (flat)
blocks that are coded equally well either way.

On a particular problem animation clip this change eliminated a large
number of false positives including some cases where the old code
selected kf several times in a row. Marginal false negatives are less
damaging typically to compression and in the problem clip there are now
a couple of cases where "visual" scene cuts are ignored because of well
correlated content across the scene cut.

Replaced some magic numbers related to this with #defines and added
explanatory comments.

Change-Id: Ia3d304ac60eb7e4323e3817eaf83b4752cd63ecf

This patch limits  the maximum arf interval length to
approximately half a second. In some low fps animations in
particular the existing code was selecting an overly long interval
which was hurting visual quality. For a sample problem test clip
(360P animation , 15fps, ~200Kbit/s) this change also improved
metrics by >0.5 db.

There may be some clips where this hurts metrics a little, but the
worst case impact visually is likely to be less than having an
interval that is much too long. On more normal material at 24
fps or higher, the impact is likely to be nil/minimal.

Change-Id: Id8b57413931a670c861213ea91d7cc596375a297

Modifies a special handling that improves rate control accuracy in
the constrained quality mode, when the undershoot and overshoot
limits are set tighter.

Change-Id: If62103f0ef3ed1cac92807400678c93da50cf046

Set the GF group adaptive max Q compile flag to 1 by default.

This change has a quite big visual impact in some clips and also
contributes to tighter rate control.

For short test clips that have consistent content the impact is
quite small on metrics but for more varied long form clips there is
a drop in overal psnr but a sharp rise in average psnr caused by
greater expenditure on some easier sections and tighter rate clipping
in hard sections.

In chunck'ed encodes some of the effect will already be present due
to the independent rate control in each chunk but this change takes
the control down to a smaller scale.

yt hd +10.67%, - 3.77%, -1.56%
yt +9.654%, - 3.6%, - 1.82%
std hd +0.25%, -0.85%, -0.42%
derf +0.25%, - 1.1%. - 0.87%

Change-Id: Ibbc39b800d99d053939f4c6712d715124082843e

Revised adjustment for rd based on source complexity.
Two cases:

1) Bias against low variance intra predictors
when the actual source variance is higher.

2) When the source variance is very low to give a slight
bias against predictors that might introduce false texture
or features.

The impact on metrics of this change across the test sets is
small and mixed.

derf -0.073%, -0.049%, -0.291%
std hd -0.093%, -0.1%, -0.557%
yt  +0.186%, +0.04%, - 0.074%
ythd +0.625%, + 0.563%, +0.584%

Medium to strong psycho-visual improvements in some
problem clips.

This feature and intra weight on GF group length now
turned on by default.

Change-Id: Idefc8b633a7b7bc56c42dbe19f6b2f872d73851e

This patch accounts in the first pass stats for blocks that
while not coded as intra, are complex and have an intra error /
best error ratio below a threshold.

The modification shortens the GF arf interval for a particular
class of content that contains a lot of blocks matching the
above criteria. (In one short problem test sequence the average
interval dropped from about 14-15 to 10-11)

The change results in small net gains in metrics results for the
Yt(~0.2%) and yt-hd (~0.5%) sets and is approximately neutral
for the other test sets.

The change is currently shielded by a flag and off by default
pending verification that it does not cause other regressions
in tests on a wider YT test set.

Change-Id: I6b803daa6a4ac09a6f428fb3a18be1ecedd974b7

Adjustment previously only enabled in VBR mode.

This patch allows adjustment of min and max q for CBR
and adjustment of max q only for CQ mode.

Change-Id: Id5e583f3d50453cd544fc57249acacd946457482

Change-Id: I87cc0e038171c60a957298827e312fead500f7fb

Frame buffers are now allocated dynamically on-demand.

Entries in the reference frame map, cm->ref_frame_map,
may now be set to -1 (INVALID_IDX) to indicate that
there is not a valid reference buffer in that "slot".

All slots in the reference frame map are now initialized
to the empty state (-1) and each buffer is initialized
to have a reference count of 0.

Change-Id: Id1afe98de98db4ae8b2dfefed7889c3b28c68582

When GF group adaptive maxQ is enabled this patch accounts
somewhat for accumulated error in the rate control.

This improves accuracy quite a bit on many clips especially
when there is  overshoot.

Examples when the overshoot and undershoot command line
parameters are set to 100:

Hall @ 1200 overshoot is reduced from 67-24%.
Akiyo @ 400 undershoot is reduced from 28%-15%.

Setting a lower value for undershoot or overshoot still
reduces the error further.

Impact on metrics is mixed with some gains in average psnr
but generally a little lower (e.g. 0.5%) on overall and ssim.

The GF group adaptation is still off by default in this patch.
Compared to with the head, enabling this mode now gives
big average psnr gains on the YT sets (e.g. YT_HD >11.2%),
a drop in overall PSNR (YT-HD 3.9%) and a smaller drop or
neutral for SSIM.

Change-Id: If4b32cd0740d3fb941317b374f9c2951954eee90

20 items in the control string but only 19 arguments.

Change-Id: I51dab9aa1c58c653b52395005a9cb41f09feb484

Note: This feature is still in development.

Add an option for the encoder to decide the resolution
at which to encode each frame.

Each KF/GF/ARF goup is tested to see if it would be
better encoded at a lower resolution. At present, each
KF/GF/ARF is coded first at full-size and if the coded
size exceeds a threshold (twice target data rate) at
the maximum active Q then the entire group is encoded
at lower resolution.

This feature is enabled in vpxenc by setting:
  --resize-allowed=1

In addition, if the vpxenc command line also specifies
valid frame dimensions using:
  --resize-width=XXXX & --resize_height=YYYY
then *all* frames will be encoded at this resolution.

Change-Id: I13f341e0a82512f9e84e144e0f3b5aed8a65402b

In frame parallel decode, libvpx decoder decodes several frames on all
cpus in parallel fashion. If not being flushed, it will only return frame
when all the cpus are busy. If getting flushed, it will return all the
frames in the decoder. Compare with current serial decode mode in which
libvpx decoder is idle between decode calls, libvpx decoder is busy
between decode calls.

Current frame parallel decode will only speed up the decoding for frame
parallel encoded videos. For non frame parallel encoded videos, frame
parallel decode is slower than serial decode due to lack of loopfilter
worker thread.

There are still some known issues that need to be addressed. For example:
decode frame parallel videos with segmentation enabled is not right sometimes.

* frame-parallel:
  Add error handling for frame parallel decode and unit test for that.
  Fix a bug in frame parallel decode and add a unit test for that.
  Add two test vectors to test frame parallel decode.
  Add key frame seeking to webmdec and webm_video_source.
  Implement frame parallel decode for VP9.
  Increase the thread test range to cover 5, 6, 7, 8 threads.
  Fix a bug in adding frame parallel unit test.
  Add VP9 frame-parallel unit test.
  Manually pick "Make the api behavior conform to api spec." from master branch.
  Move vp9_dec_build_inter_predictors_* to decoder folder.
  Add segmentation map array for current and last frame segmentation.
  Include the right header for VP9 worker thread.
  Move vp9_thread.* to common.
  ctrl_get_reference does not need user_priv.
  Seperate the frame buffers from VP9 encoder/decoder structure.
  Revert "Revert "Revert "Revert 3 patches from Hangyu to get Chrome to build:"""
 Conflicts:
       test/codec_factory.h
       test/decode_test_driver.cc
       test/decode_test_driver.h
       test/invalid_file_test.cc
       test/test-data.sha1
       test/test.mk
       test/test_vectors.cc
       vp8/vp8_dx_iface.c
       vp9/common/vp9_alloccommon.c
       vp9/common/vp9_entropymode.c
       vp9/common/vp9_loopfilter_thread.c
       vp9/common/vp9_loopfilter_thread.h
       vp9/common/vp9_mvref_common.c
       vp9/common/vp9_onyxc_int.h
       vp9/common/vp9_reconinter.c
       vp9/decoder/vp9_decodeframe.c
       vp9/decoder/vp9_decodeframe.h
       vp9/decoder/vp9_decodemv.c
       vp9/decoder/vp9_decoder.c
       vp9/decoder/vp9_decoder.h
       vp9/encoder/vp9_encoder.c
       vp9/encoder/vp9_pickmode.c
       vp9/encoder/vp9_rdopt.c
       vp9/vp9_cx_iface.c
       vp9/vp9_dx_iface.c

This reverts commit a18da976.

Change-Id: I361442ffec1586d036ea2e0ee97ce4f077585f02

Currently disabled by default: enabled using
#define GROUP_ADAPTIVE_MAXQ

In this patch the active max Q is adjusted for each GF
group based on the vbr bit allocation and raw first pass
group error.

This will tend to give a lower q for easy sections
and a higher value for very hard sections. As such it is
expected to improve quality in some of the easier
sections where quality issues have been reported.

This change tends to hurt overall psnr but help
average psnr. SSIM also shows a small gain.

Average results for derf, yt, std-hd and yt-hd test sets were
as follows (%change for average psnr, overal psnr and ssim):-

derf +0.291, - 0.252, -0.021
yt +6.466, -1.436, +0.552
std-hd +0.490, +0.014, +0.380
yt-hd +5.565, - 1.573, +0.099

Change-Id: Icc015499cebbf2a45054a05e8e31f3dfb43f944a

This reverts commit bde04ce5

Change-Id: I053dae04c761b04a36dc239558503905a14d2470

Just before a forced key frame we often get a foreshortened
arf/gf group. In such a case, we do not want to update
rc->last_boosted_qindex, which is used to define the Q range
for the forced key frame itself.

This gives a small average metrics gain for the YT and YT-HD sets
(eg. YT SSIM +0.141%).

Change-Id: Ie06698bc4f249e87183b8f8fb27ff8f3fde216d9

This patch modified struct VP9_COMP. Created a struct ThreadData
to include data that need to be copied for each thread. In
multiple thread case, one thread processes one tile. all threads
share one copy of VP9_COMP,
(refer to VP9_COMP *cpi in the code)
but each thread has its own copy of ThreadData,
(refer to ThreadData *td in the code).
Therefore, within the scope of encode_tiles(), both cpi and td
need to be passed as function parameters.

In single thread case, the FRAME_COUNTS pointer in ThreadData
points to "counts" in VP9_COMMON.

Change-Id: Ib37908b2d8e2c0f4f9c18f38017df5ce60e8b13e

Make the midpoint variance used in AQ mode 1 segmentation
depend on the overall complexity of the frame in two pass.

Change-Id: I452814ec57f7a32352e41bb250e78066abe952dd

Correct calculation of number of mbs in two pass code when
frame resizing is enabled. Always use initial number of mbs if
scaling is enabled, as this is what was used in the first pass.

Change-Id: I49a4280ab5a8b1000efcc157a449a081cbb6d410

This reverts commit 6906d218.

Another way will be used to handle mb struct.

Change-Id: Ic1111a46b2b1ee00f8f9e3fcd4cf3eb6030b2dc4

Modified VP9_COMP struct to include MACROBLOCK *mb. This change
makes it feasible in multi-thread case to allocate a mb for each
thread.

Change-Id: I624d6d1aa9c132362200753e5d90b581b1738d6e

Prepare for the introduction of frame-size change
logic into the recode loop.

Separated the speed dependent features into
separate static and dynamic parts, the latter being
those features that are dependent on the frame size.

Change-Id: Ia693e28c5cf069a1a7bf12e49ecf83e440e1d313

Add extra vp9_clear_system_state() calls to fix
double / mmx issue introduced into first pass
code for 32 bit builds.

Change-Id: I84cd2986b80d83650a091ab25c43755efeb82e03

Removed redundant weighting function tied for AQ1 from first
pass code.

Improvment in baseline AQ1 results:-
Derf  opsnr +0.142% SSIm +0.258%
YT  opsnr +0.173% SSIm +0.3%

Change-Id: I16ef91caf2d7f302cd5940cc5e2626d48ebcb212

The aim of this patch is to apply a positive weighting to
frames that have a significant number of blocks that are
of low spatial complexity and are dark. The rationale behind
this is that artifacts tend to be more visible in such frames.

In this patch the weight is only applied in regard to the distribution
of bits between frames. Hence if all the frames share similar
characteristics (as is the case for most of our short test clips) there
will be little or no net effect.

However, the effect can be seen on some longer form test content.

For example Tears of steel baseline test:
2323.09 Kbit/s opsnr 39.915 ssim 74.729
With this patch:-
2213.34 Kbit/s opsnr 39.963 ssim 74.808
(Sligtly better metrics and about 5% smaller)

The weighting may well need some further tuning along side changes
to the aq modes.

Change-Id: Ieced379bca03938166ab87b2b97f55d94948904c

Added code to relax the active maximum Q in response
to extreme local overshoot to reduce bandwidth peaks.

The impact is small in metrics terms, but it this helps reduce
bandwidth spikes and overall overshoot in a number of
clips in our tests sets (especially the YT test set).

In particular this should help prevent very big spikes where a clip
is mainly easy but has a short hard section. In such a case a choice
of maximum Q for the clip as a whole may allow us to hit the overall
target rate but give some extreme spikes. The chunked encoding in YT
mitigates this problem but it can show up where a longer clip is
coded as a single chunk.

Change-Id: I213d09950ccb8489d10adf00fda1e53235b39203

The point at which frames are scaled to their
coded dimensions is moved into the re-code loop.

This is in preparation for a further patch that
will add logic into the re-code loop to reduce
the coded frame size if the encoder is struggling
to hit the target data rate at the native frame
size.

Change-Id: Ie4131f5ec6fb93148879f6ce96123296442bf2d1

Delete gfboost_qadjust() and move Q based adjustment
into calc_frame_boost(). Also remove clamping. Making
the adjustment here means that it influences not just the
boost level but also the selection of the GF/ARF interval.

This change gives a small average gain in PSNR but
larger gains in SSIM, especially for harder std-hd set (1.5%)

Change-Id: I3aa81b8feccaeff93d915e19fb9cf5cd64c86327

We encode a empty invisible frame in front of the base layer frame to
avoid using prev_mi. Since there's a restriction for reference frame
scaling factor, we have to make it smaller and smaller gradually until
its size is 16x16.

Change remerged.

Change-Id: I9efab38bba7da86e056fbe8f663e711c5df38449

This reverts commit 452dc215.

This change has introduced a significant quality regression on content
with forced key frames. (e.g. the YT and yt-hd set). It is most
noticeable in static content where the kf bits dominate. Here, despite
key frames being apparently coded at the same Q, there is a drop in all
metrics of ~20% (e.g clXR and BFa0).

Change-Id: Iba14cc61778c0846fa0a59c33c55a9fc49512cb4

This reverts commit c113457a.

Temporary revert to allow clean revert of another commit.

Change-Id: Ia9b7b755e6c48e1b6e383329f121fef175a24b27

We encode a empty invisible frame in front of the base layer frame to
avoid using prev_mi. Since there's a restriction for reference frame
scaling factor, we have to make it smaller and smaller gradually until
its size is 16x16.
Change-Id: I60b680314e33a60b4093cafc296465ee18169c19

Move the point at which input frames are scaled
into the recode loop. This will allow us to change
the coded frame size dynamically in response
to previous attempts to encode the frame at a
higher resolution.

A following patch will implement a scheme for
resizing the frame in the recode loop.

Change-Id: I6a59c02d6ac1626512edad6de8b60063b79433e6

Add back clamp which ensures that the Q adaptation
is turned off when the over_shoot_pct and under_shoot_pct
parameters are set to 100.

Change-Id: Id0161b114d39a3029cd3eb28020caab0c3914922

Allow min and maxQ to creep when the undershoot
or overshoot exceeds thresholds controlled by the
command line under_shoot_pct and over_shoot_pct
values.

Default is 100%,100% which ~disables adaptation.

Derf results for example undershoot% / overshoot%:-

Head:- Mean abs (%rate error) = 14.4%

This check in:-
25%/25% - Mean abs (%rate error) = 6.7%
                  PSNR hit -1% SSIM -0.1%

5% / 5%  - Mean abs (%rate error) = 2.2%
                 PSNR hit -3.3% SSIM - 1.1%

Most of the remaining error and most of the quality hit is
at extreme data rates. The adaptation code still has an
exception for material that is in effect static so that we
don't over adjust and over spend on YT slide show type
content.

(Rebase of If25a2449a415449c150acff23df713e9598d64c9
to resolve a auto-merge error)

Change-Id: Iec4e1613ef0d067454751d8220edb7058dfbd816

This reverts commit 869d4ca5.

This breaks the build via conflict with
e18edd5e.

Change-Id: If544b99e367a449452834eb8cce600f58c34ec0d

Allow min and maxQ to creep when the undershoot
or overshoot exceeds thresholds controlled by the
command line under_shoot_pct and over_shoot_pct
values.

Default is 100%,100% which ~disables adaptation.

Derf results for example undershoot% / overshoot%:-

Head:- Mean abs (%rate error) = 14.4%

This check in:-
25%/25% - Mean abs (%rate error) = 6.7%
                  PSNR hit -1% SSIM -0.1%

5% / 5%  - Mean abs (%rate error) = 2.2%
                 PSNR hit -3.3% SSIM - 1.1%

Most of the remaining error and most of the quality hit is
at extreme data rates. The adaptation code still has an
exception for material that is in effect static so that we
don't over adjust and over spend on YT slide show type
content.

Change-Id: If25a2449a415449c150acff23df713e9598d64c9

Uses highbd_ prefix convention consistently.

Change-Id: I58f7f799a7ff8e32701bcd71c955bcf1cdd4581e

In model_rd_for_sb function, the spatial domain SSE and variance
are checked to see if transform coefficients are quantized to 0.
Besides that, this patch adds another set of thresholds that are
much more strict. These thresholds are used to conduct a partition
block level check to measure if all its TX blocks are skippable
for YUV planes. If it is true, x->skip is set for this partition
block, and thus its mode search is terminated.

This speeds up the encoding at very low prediction error case,
such as screen sharing application. This patch covers what
rd_encode_breakout_test() does, so that function is removed.

Borg test at speed 3 shows:
For stdhd set, psnr: +0.008%, ssim: +0.014%;
For derf set, psnr: +0.018%, ssim: +0.025%.
No noticeable speed change.

Change-Id: I4e5f15cf10016a282a68e35175ff854b28195944

Adjustments to the GF interval choice and minimum boost.
Adjustment to the calculation of 2 pass worst q.
Compared to 09/29 head there is metrics hit on derf of
(-0.123%,-0.191%)

Compared to the September 29 head and a baseline on
September 18 baseline the accuracy of the VBR rate control
measured on the derf set is as follows:-

Mean error %  / Mean abs(error %)
Sept 18 baseline (-7.0% / 14.76%)
Sept 29 head (-15.7%, 19.8%)
This check in (-1.5% / 14.4%)

The mean undershoot is reduced slightly but the
worst case overshoot on e.g. harbour/highway is
increased. This will be addressed in a later patch.

Change-Id: Iffd9b0ab7432a131c98fbaaa82d1e5b40be72b58