Move rectangular superblock coding out of experimental list.

Change-Id: I96c37547d122330d666a67b4bf577ae54547857f

This commit enables selecting probability models for recursive block
partition information syntax, depending on its above/left partition
information, as well as the current block size. These conditional
probability models are reasonably stationary and consistent across
frames, hence the backward adaptive approach is used to maintain and
update the contextual models.

It achieves coding performance gains (on top of enabling rectangular
block sizes):
derf:   0.242%
yt:     0.391%
hd:     0.376%
stdhd:  0.645%

Change-Id: Ie513d9673337f0d27abd65fb566b711d0844ec2e

Also some further simplification following removal
of top node code.

There is an issue in regards to the shared file vp8cx.h
in regard to the roi_map as this interface assumes that
there are only 4 segments. I have left the value here as
4 for now meaning that the roi_map interface is broken
for VP9.

Note that this change would have been easier if I hadn't
had to search for hard wire instances of the number 4
and <= 3.

Change-Id: Ia8b6deea4be4dbd20deb1656e689dd43a5f190e8

Remove top node optimization.
The improvement this gives is not sufficient to justify
the extra complexity.

Change-Id: I2bb4a12a50ffd52cacfa4a3e8acbb2e522066905

Change-Id: Iaef16122732c2a81e0927f9862b51b68dc788712

Change-Id: I54acef342b8e787e05af0febd7cf0d7d10288383

This fixes an intermittent mismatch issue cause by moving
the lossless mode decoding bit to after the loop filter
setup information. We need to ensure that the lossless bit
is decoded prior to loop filter setup.

Change-Id: I3faa3fff8e1013b7405dac91268350e059ed121e

This patch does not seem to give any benefits.

Change-Id: I9d2b4091d6af3dfc0875f24db86c01e2de57f8db

Adds an experiment that codes an end-of-orientation symbol
for every eligible zero encountered in scan order.

This cleans out various other sub-experiments that were part
of the origiinal patch, which will be later included if found
useful.

Results are slightly positive on all sets (0.1 - 0.2% range).

Change-Id: I57765c605fefc7fb9d1b57f1b356843602abefaf

Change-Id: Iff35d4b2f8f65511f80c594958c01fb4673fa033

Change-Id: Ie4713da125e954c1d30e1d4cbeb38666fce90ccc

This experiment has failed to give much benefit but
does add complexity so deprecated.

Change-Id: Ic7b929ba706390b9907ef0b4f965bd401ca799a4

Change-Id: I183ec5819d4d80966c92db36db75b8c3be0d381d

Moving all the probability updates after frame context selection.
This makes it clean and simple to store all the probs in single
struct that can be sent to hardware codec.

Change-Id: I2ec3de81adbd468d8ef34a914caae80a18c3ef56

Enable recursive partition information coding from SB64X64 down to
MB16X16. The bit-stream syntax is now supporting rectangular block
sizes. It starts from SB64X64 and recursively describes the partition
type of the current block. If the partition type is PARTITION_NONE,
the block is coded as a single unit; if it is PARTITION_HORZ or
PARTITION_VERT, the block is segmented into two independently coded
rectangular units, with no further partition needed; otherwise, the
block is segmented into 4 square blocks. i.e., PARTITION_SPLIT case,
each can be potentially further partitioned.

Forward adaptive probability modeling is used for the partition
information coding, conditioned on the current block size.

Change-Id: I499365fb547839d555498e3bcc0387d8a3587d87

Change-Id: I7057ed8e2a13a3c5367e2923eb4b3260bd7cf546

Change-Id: Ic795cf6fc202bf32c9b5b0b3cef9ac422af53cd0

New names are y_dc_delta_q, uv_dc_delta_q, uv_ac_delta_q.

Change-Id: I4acae1fc23a4697ce2c5a5becb8dc28ef0a4b552

This flag was added to VP8 to allow a mode where MB-level skipping
was not allowed, saving a bit per mb. It was never used in practice,
and hasn't been tested in VP9, so remove it.

Change-Id: Id450ec6904c6d06c1919508e7efc52d05cde5631

This is work-in-progress, it implements multiple ARF
encoding behind an experimental flag.

It adds the ability to insert multiple ARF frames into a
single ARF group. This patch implements the reordering
of the coded frames, and implements a fixed-length coding
pattern. It applies a fixed quantizer strategy based on
where the frame is in the coding sequence.

Further work to modify the rate control strategy is
ongoing and will be submitted via a set of future patches.

In this first step, each ARF group is recursively
bisected and an ARF frame added at that position in the
sequence. The recursion continues until ARF frames are
within MIN_GF_INTERVAL frames.

The code sits behind the "multiple-arf" experimental
flag ("CONFIG_MULTIPLE_ARF"). The experimental flag
"oneshotq" ("CONFIG_ONESHOTQ") also needs to be enabled
for this patch to work correctly.

Change-Id: Ie473b05ebb43ac473c0cfb659b2b8042823085e2

So it is consistent with I8x8_PRED.

Change-Id: Iefa65124b2419690d83e526c611129c0ede29d11

This patch changes the default with the modecoefprob expt
to use mode-based forward updates with one-node pegged
modeling.

The maximum difference with fully trained tables is now
less that 0.1%.

Change-Id: I06b44322e10c6703f93f3c1d48d973b1136a0618

Change-Id: If69c3d795f87af5cc7bfdfe70ef733c41b4d55c8

With these fixed, the codec produces identical results regardless of
what literal values are used for the enum members in BLOCK_SIZE_*.

Change-Id: I26db8e08019b58ba432af1f0950ebe6b0eb4ad8c

Change-Id: I0d12f9ef9d960df0172a1377f8e5236eb6d90492

Lower case variable names, less code.

Change-Id: I1abc8f592ad2343ab5c76fe2d16262741a4a894a

Renaming sb32_coded to prob_sb32_coded and sb64_coded to prob_sb64_coded.

Change-Id: I6de5cad00a57c3e066d53467f8c38cb6073dce11

The patch adds the flexibility to use standard EOB based coding
on smaller block sizes and nzc based coding on larger blocksizes.
The tx-sizes that use nzc based coding and those that use EOB based
coding are controlled by a function get_nzc_used().
By default, this function uses nzc based coding for 16x16 and 32x32
transform blocks, which seem to bridge the performance gap
substantially.

All sets are now lower by 0.5% to 0.7%, as opposed to ~1.8% before.

Change-Id: I06abed3df57b52d241ea1f51b0d571c71e38fd0b

Change-Id: I4a3a9eb9f9d17218a0f0d7e148123d34dae879c2

Pearson correlation for above or left is significantly higher than for
previous-in-scan-order (absolute values depend on position in scan, but
in general, we gain about 0.1-0.2 by using either above or left; using
both basically just makes this even better). For eob branch skipping,
we continue to use the previous token in scan order.

This helps about 0.9% on derf after re-training on a limited data set.
Full re-training and results on larger-resolution clips are pending.

Note that this commit breaks trellis, so we can probably get further
gains out of it by fixing trellis at some later point.

Change-Id: Iead68e296fc3a105cca746b5e3da9555d6010cfe

Adds a per-frame, strength adjustable, in loop deringing filter. Uses
the existing vp9_post_proc_down_and_across 5 tap thresholded blur
code, with a brute force search for the threshold.

Results almost strictly positive on the YT HD set, either having no
effect or helping PSNR in the range of 1-3% (overall average 0.8%).
Results more mixed for the CIF set, (-0.5 min, 1.4 max, 0.1 avg).
This has an almost strictly negative impact to SSIM, so examining a
different filter or a more balanced search heuristic is in order.

Other test set results pending.

Change-Id: I5ca6ee8fe292dfa3f2eab7f65332423fa1710b58

Replaces the default tables for single coefficient magnitudes with
those obtained from an appropriate distribution. The EOB node
is left unchanged. The model is represeted as a 256-size codebook
where the index corresponds to the probability of the Zero or the
One node. Two variations are implemented corresponding to whether
the Zero node or the One-node is used as the peg. The main advantage
is that the default prob tables will become considerably smaller and
manageable. Besides there is substantially less risk of over-fitting
for a training set.

Various distributions are tried and the one that gives the best
results is the family of Generalized Gaussian distributions with
shape parameter 0.75. The results are within about 0.2% of fully
trained tables for the Zero peg variant, and within 0.1% of the
One peg variant.

The forward updates are optionally (controlled by a macro)
model-based, i.e. restricted to only convey probabilities from the
codebook. Backward updates can also be optionally (controlled by
another macro) model-based, but is turned off by default. Currently
model-based forward updates work about the same as unconstrained
updates, but there is a drop in performance with backward-updates
being model based.

The model based approach also allows the probabilities for the key
frames to be adjusted from the defaults based on the base_qindex of
the frame. Currently the adjustment function is a placeholder that
adjusts the prob of EOB and Zero node from the nominal one at higher
quality (lower qindex) or lower quality (higher qindex) ends of the
range. The rest of the probabilities are then derived based on the
model from the adjusted prob of zero.

Change-Id: Iae050f3cbcc6d8b3f204e8dc395ae47b3b2192c9

Renaming Width to width, Height to height and Version to version in
several structs and function signatures.

Change-Id: I084c3f7e747cb2ce3345aff27a3dff9b13a87543

If the intended display size is different than the size the frame is
coded at, then send that size explicitly in the bitstream. Adds a new
bit to the frame header to indicate whether the extra size fields
are present.

Change-Id: I525c66f22d207efaf1e5f903c6a2a91b80245854

The automatic merge result was incomplete.

Change-Id: I8976318bfc346d867660a013a302c80edb25fc29

The previous implementation visited each node in the tree multiple times
because it used each symbol's encoding to revisit the branches taken and
increment its count. Instead, we can traverse the tree depth first and
calculate the probabilities and branch counts as we walk back up. The
complexity goes from somewhere between O(nlogn) and O(n^2) (depending on
how balanced the tree is) to O(n).

Only tested one clip (256kbps, CIF), saw 13% decoding perf improvement.

Note that this optimization should port trivially to VP8 as well. In VP8,
the decoder doesn't use this function, but it does routinely show up
on the profile for realtime encoding.

Change-Id: I4f2848e4f41dc9a7694f73f3e75034bce08d1b12

Adds probability updates for extra bits for the nzcs, code for
getting nzc stats, plus some minor cleanups and fixes.

Change-Id: If2814e7f04fb52f5025ad9f400f3e6c50a00b543

This patch revamps the entropy coding of coefficients to code first
a non-zero count per coded block and correspondingly remove the EOB
token from the token set.

STATUS:
Main encode/decode code achieving encode/decode sync - done.
Forward and backward probability updates to the nzcs - done.
Rd costing updates for nzcs - done.
Note: The dynamic progrmaming apporach used in trellis quantization
is not exactly compatible with nzcs. A suboptimal approach has been
used instead where branch costs are updated to account for changes
in the nzcs.

TODO:
Training the default probs/counts for nzcs

Change-Id: I951bc1e22f47885077a7453a09b0493daa77883d

Split macroblock and superblock tokenization and detokenization
functions and coefficient-related data structs so that the bitstream
layout and related code of superblock coefficients looks less like it's
a hack to fit macroblocks in superblocks.

In addition, unify chroma transform size selection from luma transform
size (i.e. always use the same size, as long as it fits the predictor);
in practice, this means 32x32 and 64x64 superblocks using the 16x16 luma
transform will now use the 16x16 (instead of the 8x8) chroma transform,
and 64x64 superblocks using the 32x32 luma transform will now use the
32x32 (instead of the 16x16) chroma transform.

Lastly, add a trellis optimize function for 32x32 transform blocks.

HD gains about 0.3%, STDHD about 0.15% and derf about 0.1%. There's
a few negative points here and there that I might want to analyze
a little closer.

Change-Id: Ibad7c3ddfe1acfc52771dfc27c03e9783e054430

Fixed a couple of variable/function definitions, as well as header
handling to support 16K sequence coding at high bit-rates.

The width and height are each specified by two bytes in the header.
Use an extra byte to explicitly indicate the scaling factors in
both directions, each ranging from 0 to 15.

Tested coding up to 16400x16400 dimension.

Change-Id: Ibc2225c6036620270f2c0cf5172d1760aaec10ec