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This is to avoid a rare encoder/decoder mismatch for MB using SPLITMV
mode. In decoder, the UV mv can be determined to need clamp, but the
flag is never set in encoder motion vector selection process, and the
clamp is not done in encoding in encoder.

Change-Id: I60520d3f790354c7855dadf03f0978ea9b77e2c0

This commit adds lossless compression capability to the experimental
branch. The lossless experiment can be enabled using --enable-lossless
in configure. When the experiment is enabled, the encoder will use
lossless compression mode by command line option --lossless, and the
decoder automatically recognizes a losslessly encoded clip and decodes
accordingly.

To achieve the lossless coding, this commit has changed the following:
    1. To encode at lossless mode, encoder forces the use of unit
quantizer, i.e, Q 0, where effective quantization is 1. Encoder also
disables the usage of 8x8 transform and allows only 4x4 transform;
    2. At Q 0, the first order 4x4  DCT/IDCT have been switched over
to a pair of forward and inverse Walsh-Hadamard Transform
(http://goo.gl/EIsfy),  with proper scaling applied to match the range
of the original 4x4 DCT/IDCT pair;
    3. At Q 0, the second order remains to use the previous
walsh-hadamard transform pair. However, to maintain the reversibility
in second order transform at Q 0, scaling down is applied to first
order DC coefficients prior to forward transform, and scaling up is
applied to the second order output prior to quantization. Symmetric
upscaling and downscaling are added around inverse second order
transform;
    4. At lossless mode, encoder also disables a number of minor
features to ensure no loss is introduced, these features includes:
        a. Trellis quantization optimization
        b. Loop filtering
        c. Aggressive zero-binning, rounding and zero-bin boosting
        d. Mode based zero-bin boosting

Lossless coding test was performed on all clips within the derf set,
to verify that the commit has achieved lossless compression for all
clips. The average compression ratio is around 2.57 to 1.
(http://goo.gl/dEShs)

Change-Id: Ia3aba7dd09df40dd590f93b9aba134defbc64e34

Added the ability to optionally filter the prediction data
when inter modes are selected (excludes SPLITMV, for now).

The mode selection loop considers both the filtered and
non-filtered prediction data when choosing mode. The filter
can be turned on/off at the frame-level, or signaled for
each MB.

Change-Id: I1b783c71d95a361ab36c761b07e8a6b06bc36822

Incorporates mv_ref, mbsplit and second_mv into the adaptive
entropy framework. The mv_ref framework has been modified from
before.

Adds some clean-ups and fixes.

Results with the adaptive entropy experiment are currently up by
+1.93% on derf; +2.33% std-hd and +1.87% yt-hd.

Fixed a nasty intermittent bug.

Change-Id: I4b1ac9f9483b48432597595195bfec05f31d1e39

Change-Id: I6cbd4de96f9dcc783cef170bfd7652f6cbee36a2

Change-Id: I883b4f63559c1cf66a25016e946b1b1ae98a20da

Change-Id: I6802731a4d15feef5ce62993dc505ded55c40f7e

Change-Id: Iec81423e8e6c50acd9e10f69bc99ad0e9058517d

This patch incorporates adaptive entropy coding of coefficient tokens,
and mode/mv information based on distributions encountered in a frame.
Specifically, there is an initial forward update to the probabilities
in the bitstream as before for coding the symbols in the frame, however
at the end of decoding each frame, the forward update to the
probabilities is reverted and instead the probabilities are updated
towards the actual distributions encountered within the frame.
The amount of update is weighted by the number of hits within each
context.

Results on derf/hd/std-hd are all up by 1.6%.

On derf, the most of the gains come from coefficients, however for the
hd and std-hd sets, the most of the gains come from the mode/mv
information updates.

Change-Id: I708c0e11fdacafee04940fe7ae159ba6844005fd

Updates idct/dequant mmx assembly to work with vpnext instead of vp8.

Also adds x86inc.asm

Change-Id: I6e147d5e89177ae449271e97e50d082eb11b078e

This commit is to remove two arrays, which contain the probabilities
of how likely each probability in coef_probs table is updated. The
commit changed to use a fixed number "252".

Surprisedly, the overall impact on quality is close to zero, which
basically says the two big static arrays are not helpful at all.
derf: -0.016%, -0.020%
std-hd: 0.000%, -0.013%
yt: -0.022%, +0.007%
yt-hd: -0.038%, +0.034%

Change-Id: Ifee94d28a37dcab4f1d2b994bd5b07575be42b72

the commit fixed a number of compiling issues when some epxeriments
are turned on at the same time.

Change-Id: Idb15b215e2d2a7d25f2707f99ef55a34e7301ce7

The commit changed how baseline 8x8 coefficient probabilities are
initialized, to be consistent with the initialization of baseline
4x4 coefficient probabilities.

The commit does not have any effect on compression.

Change-Id: Ifb3902b5dc0b0c2e6dc3aa5d4a6589d528e58355

I now see I didn't write a very long description, so let's do it
here then. We took a pretty big quality hit (0.1-0.2%) from my
recent fix of the inversion of arguments to vp8_cost_bit() in the
RD reference frame costing. I looked into it and basically the
costing prevented us from switching reference frames. This is of
course silly, since each frame codes its own prob_intra_coded, so
using last frame cost indications as a limiting factor can never
be right.

Here, I've rewritten that code to estimate costings based partially
on statistics from progress on current frame encoding. Overall,
this gives us a ~0.2%-0.3% improvement over what we had previously
before my argument-inversion-fix, and thus about ~0.4% over current
git (on derf-set), and a little more (0.5-1.0%) on HD/STD-HD/YT.

Change-Id: I79ebd4ccec4d6edbf0e152d9590d103ba2747775

Adds 6 directional intra predictiom modes for 16x16 and 8x8 blocks.

Change-Id: I25eccc0836f28d8d74922e4e9231568a648b47d1

This commit changed the forward and the inverse 4x4 Walsh Hadamard
transform to a new pair, where the inverse transform can pefectly
reconstuct the input to forward transform. It also does so without
changing the input and output value range. Even more, it does not
change the complexity of the transforms.

While it was not expected to improve the results of our current test,
it does improve std-hd set by 0.2% on all metrics. No change on derf.

Change-Id: Ie4f23ddd3a0f3c5fbe97fb58399f860031f99337

Also includes some clean ups and refactoring.

Rebased.

Change-Id: I268c97fe325b4881103fe19f41ae818569e7ccf7

1. block types
There are only three types of blocks for 8x8 transformed MBs, i.e. Y
block with DC does not exist for 8x8 transformed MBs as all MB using
8x8 transform have 2nd order haar transform. This commit introduced
a new macro BLOCK_TYPES_8X8 to reflect such fact.

2. context counters
This commit also fixed the mixed of context_counters between 4x4 and
8x8 transformed MBs. The mixed use of the counters leads me to think
the existing the context probabilities were not properly generated
from 8x8 transformed MBs.

3. redundant collecting in recoding
The commit also corrected the code that accumulates entropy stats by
making sure stats only collected for final packing, not during the
recode loop

Change-Id: I029f09f8f60bd0c3240cc392ff5c6d05435e322c

This patch expands the set of prev contexts used for video coding
from 3 to 4.

There is a small improvement of the order of 0.08% for derf and
0.15% on the HD set. The tests were rerun after the various merges
last week. There are two columns in each test - the first are the
results with the mbskip change, and the second with expanded contexts
added on top of that.

Derf:
http://www.corp.google.com/~debargha/vp8_results/explibvpx_newentropy_expcontext.html

HD:
http://www.corp.google.com/~debargha/vp8_results/explibvpx_hd_newentropy_expcontext.html

Rebased.

Broke up 80 char lines.

Change-Id: I82d2e72d054e530cbf5ce9aa0e6d85c582965675

This commit adjusted slightly the 4x4 coefficents band definition to
better classify coefficients with similar distributions and usages.
It helps derf set about .1%, it is alos slightly positive for std-hd
set, where 4x4 blocks are used less frequently.

The commit also removed a const array not in use.

Change-Id: I78d16905d4036641ec905b0c32c190c1def5b249

This commit merge the QI mode experiment. As the experiment affects
the encoding of intra coding modes on key frame only, the overall
effect of the experiment on encoding tests is insignificant.

Change-Id: I9e4e3933adface88867ad429cee3986e529c511d

The commit merges the UVINTRA experiment and removed the related
macros. The overall effect of the experiment is a small gain (.1%
on derf)

Change-Id: Ia34b3312fb9b5b34c9ba111bf0fa78c6f78ac80b

Change-Id: I8708358bb37edabcbe5dfc755ed18791d9e143c4

Adds differential encoding of prob updates using a subexponential
code centered around the previous probability value.
Also searches for the most cost-effective update, and breaks
up the coefficient updates into smaller groups.

Small gain on Derf: 0.2%

Change-Id: Ie0071e3dc113e3d0d7ab95b6442bb07a89970030

Change-Id: I9d6083d54e3d478ec20dc6dc48d3f45eb5c7e16b

Change-Id: I0af3395500b1cb0ed629249eb6636a0c9322cb18

Some code re-factored / moved to allow the main
pack operation inside the recode loop so  that the
size estimate is accurate.

Deletion of some redundant code relating to one pass.

Aproximate improvement over March 27 code base:
Derf 0.0%, YT 0.5%, YThd 0.3% Std_hd 0.25%

Change-Id: Id2d071794ab44f0b52935f6fcdb5733d09a6bb86

This is the first patch to add superblock (32x32) coding
order capabilities. It does not yet do any mode selection
at the SB level, that will follow in a further patch.

This patch encodes rows of SBs rather than
MBs, each SB contains 2x2 MBs.

Two intra prediction modes have been disabled since they
require reconstructed data for the above-right MB which
may not have been encoded yet (e.g. for the bottom right
MB in each SB).

Results on the one test clip I have tried (720p GIPS clip)
suggest that it is somewhere around 0.2dB worse than the
baseline version, so there may be bugs.

It has been tested with no experiments enabled and with
the following 3 experiments enabled:
  --enable-enhanced_interp
  --enable-high_precision_mv
  --enable-sixteenth_subpel_uv
in each case the decode buffer matches the recon buffer
(using "cmp" to compare the dumped/decoded frames).
Note: Testing these experiments individually created
errors.

Some problems were found with other experiments but it
is unclear what state these experiments are in:
  --enable-comp_intra_pred
  --enable-newentropy
  --enable-uvintra

This code has not been extensively tested yet, so there
is every likelihood that further bugs remain. I also
intend to do some code cleanup & refactoring in tandem
with the next patch that adds the 32x32 modes.

Change-Id: I1eba7f740a70b3510df58db53464535ef881b4d9

Various refactoring to make the subpel motion compensation
filters switchable by a frame level field.
Two types of 8-tap filters are supported in addition to the existing
bilinar and sixtap filters. One is the default 8-tap and the
other has a sharper cut-off for use with frames with substantial
edge content.

Patch 2: Added a preliminary strategy for filter selection based on
edginess detecton. Also includes some filter changes.

Change-Id: I866085bda5ae143cfdf2ec88157feaabdf7bd63a

Using contextual coding of the mkb_skip_coeff flag using the
values of this flag from the left and above. There is a small
improvement of about 0.15% on Derf:
http://www.corp.google.com/~debargha/vp8_results/mbskipcontext.html

Refactored to use pred_common.c by adding a new context type.

Results on HD set (about 0.66% improvement):
http://www.corp.google.com/~debargha/vp8_results/mbskipcontext_hd.html

Incliding missing refactoring to use the pred_common utilities.

Change-Id: I95373382d429b5a59610d77f69a0fea2be628278

The commit added a clamp to the 2nd motion vector used in compound
prediction to insure mv within UMV borders. The clamp is similar to
that of the first motion vector except that No SPLITMV is ever used
for the 2nd motion vector.

Change-Id: I26dd63c304bd66b2e03a083749cc98c641667116

This is a code snapshot of experimental work currently ongoing for a
next-generation codec.

The codebase has been cut down considerably from the libvpx baseline.
For example, we are currently only supporting VBR 2-pass rate control
and have removed most of the code relating to coding speed, threading,
error resilience, partitions and various other features.  This is in
part to make the codebase easier to work on and experiment with, but
also because we want to have an open discussion about how the bitstream
will be structured and partitioned and not have that conversation
constrained by past work.

Our basic working pattern has been to initially encapsulate experiments
using configure options linked to #IF CONFIG_XXX statements in the
code. Once experiments have matured and we are reasonably happy that
they give benefit and can be merged without breaking other experiments,
we remove the conditional compile statements and merge them in.

Current changes include:
* Temporal coding experiment for segments (though still only 4 max, it
  will likely be increased).
* Segment feature experiment - to allow various bits of information to
  be coded at the segment level. Features tested so far include mode
  and reference frame information, limiting end of block offset and
  transform size, alongside Q and loop filter parameters, but this set
  is very fluid.
* Support for 8x8 transform - 8x8 dct with 2nd order 2x2 haar is used
  in MBs using 16x16 prediction modes within inter frames.
* Compound prediction (combination of signals from existing predictors
  to create a new predictor).
* 8 tap interpolation filters and 1/8th pel motion vectors.
* Loop filter modifications.
* Various entropy modifications and changes to how entropy contexts and
  updates are handled.
* Extended quantizer range matched to transform precision improvements.

There are also ongoing further experiments that we hope to merge in the
near future: For example, coding of motion and other aspects of the
prediction signal to better support larger image formats, use of larger
block sizes (e.g. 32x32 and up) and lossless non-transform based coding
options (especially for key frames). It is our hope that we will be
able to make regular updates and we will warmly welcome community
contributions.

Please be warned that, at this stage, the codebase is currently slower
than VP8 stable branch as most new code has not been optimized, and
even the 'C' has been deliberately written to be simple and obvious,
not fast.

The following graphs have the initial test results, numbers in the
tables measure the compression improvement in terms of percentage. The
build has  the following optional experiments configured:
--enable-experimental --enable-enhanced_interp --enable-uvintra
--enable-high_precision_mv --enable-sixteenth_subpel_uv

CIF Size clips:
http://getwebm.org/tmp/cif/
HD size clips:
http://getwebm.org/tmp/hd/
(stable_20120309 represents encoding results of WebM master branch
build as of commit#7a159071)

They were encoded using the following encode parameters:
--good --cpu-used=0 -t 0 --lag-in-frames=25 --min-q=0 --max-q=63
--end-usage=0 --auto-alt-ref=1 -p 2 --pass=2 --kf-max-dist=9999
--kf-min-dist=0 --drop-frame=0 --static-thresh=0 --bias-pct=50
--minsection-pct=0 --maxsection-pct=800 --sharpness=0
--arnr-maxframes=7 --arnr-strength=3(for HD,6 for CIF)
--arnr-type=3

Change-Id: I5c62ed09cfff5815a2bb34e7820d6a810c23183c

The commit added a clamp to the 2nd motion vector used in compound
prediction to insure mv within UMV borders. The clamp is similar to
that of the first motion vector except that No SPLITMV is ever used
for the 2nd motion vector.

Change-Id: I26dd63c304bd66b2e03a083749cc98c641667116

Removed the copy in encoder and changed to use the one in common

Change-Id: Ief0985a50ffd6053a269638fd4816b055ca273ec

The commit changed to compute UV intra RD estimates for 4x4 and 8x8
separately to be used in mode decision for MB modes associated with
the appropriate transform size respectively. Now finally after many
other changes related 8x8 quantizer zbin boost and zbin_mode_boost,
this change overall helps the HD(with 8x8) by around ~.13%.
(avg .13%  glb .13% ssim .17%)

The commit also has a few changes for eliminating compiler warnings.

Change-Id: Ibab35dad44820c87e6b44799c66f8d519cc37344

Change-Id: I8e9b6b154e1a0d0cb42d596366380d69c00ac15f

Change-Id: Ibcd2b9b247ff9f83331dac47f91ec285e8955ff1

Also remove duplicate build_intra_predictors_mby/uv().

Change-Id: I78607e7304952a9b962a5b25af9bb9c48692187b

This is the first patch for refactoring of the code related to
high-precision mv, so that 1/4 and 1/8 pel motion vectors can
co-exist in the same bit-stream by use of a frame level flag.
The current patch works fine for only use of 1/4th and
only use of 1/8th pel mv, but there are some issues with the
mode switching in between. Subsequent patches on this change Id
will fix the remaining issues.

Patch 2: Adds fixes to make sure that multiple mv precisions can
co-exist in the bit-stream. Frame level switching has been tested
to work correctly.

Patch 3: Fixes lines exceeding 80 char

Patch 4:
http://www.corp.google.com/~debargha/vp8_results/enhinterp.html

Results on derf after ssse3 bugfix, compared to everything
enabled but the 8-tap, 1/8-subpel and 1/16-subpel uv. Overall the
gains are about 3% now. Hopefully there are no more bugs lingering.
Apparently the sse3 bug affected the quartel subpel results more than
the eighth pel ones (which is understandabale because one bad predictor
due to the bug, matters less if there are a lot more subpel options
available as in the 1/8 subpel case).
The results in the 4th column correspond to the current settings.
The first two columns correspond to two settings of adaptive switching
of the 1/4 or 1/8 subpel mode based on initial Q estimate. These
do not work as good as just using 1/8 all the time yet.

Change-Id: I3ef392ad338329f4d68a85257a49f2b14f3af472

Merge of the NEWLPF configuration experiment so it is always on.

Change-Id: I7054772b6eab28bad1ff807bfa54d98f83de9308