(1) Work with var-refs to remove redundant bits in ref frame
    coding;
(2) Add a new uni-directional compound reference pair:
    (LAST_FRAME, LAST3_FRAME);
(3) Redesign the contexts for encoding uni-directional reference frame
    pairs;
(4) Use aom_entropy_optimizer to collect stats for all the default
    probability setups related to the coding of reference frames.

Compared against the baseline (default enabled tools excluding ext-tx
and global-motion for encoder speed concern) with one-sided-compound,
the coding gain of ext-comp-refs + var-refs - one-sided-compound is:

lowres: avg_psnr -0.385%; ovr_psnr -0.378% ssim -0.344%
midres: avg_psnr -0.466%; ovr_psnr -0.447% ssim -0.513%

AWCY - High Latency:
   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-0.2758 | -0.1526 | -0.0965 |  -0.2581 | -0.2492 | -0.2534 |    -0.2118

AWCY - Low Latency:
   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-1.0467 | -1.4500 | -0.9732 |  -0.9928 | -1.0407 | -1.0180 |    -1.0049

Compared against the baseline (default enabled tools excluding ext-tx
and global-motion for encoder speed concern) without
one-sided-compound, the coding gain of
ext-comp-refs + var-refs - one-sided-compound is:

lowres: avg_psnr -0.875%; ovr_psnr -0.877% ssim -0.895%
midres: avg_psnr -0.824%; ovr_psnr -0.802% ssim -0.843%

Change-Id: I8de774c9a74c20632ea93ccb0c17779fa94431cb

This required moving the CDEF and lr signaling in the
uncompressed header to after segmentation is signaled.

The all_lossless logic was factored out into onyxc_int.h.

Change-Id: If8de03438d4e9f8cb49ed49b60a880962cc9d28b

Support the transform block kernel coding for rectangular
transform block size in var-tx. This integrates txk-sel with
var-tx.

Change-Id: I9a8edd84812168f56c79b78cc9af34f6304b1d54

this warning is covered by an assert and other runtime detection.
expanding the array, adding a conditional or converting the type to int
are less desirable.

BUG=aomedia:578

Change-Id: Idb6a1dec5f17db85a0e9c1d0ee372e701f4e1aa4

Extract the compution of the luma reconstructed average out of cfl_load
and into cfl_compute_average. The reconstructed luma average is stored
in the CFL_CONTEXT to avoid computing it for each transform block and
for each plane.

Results on subset1 (compared to 803bea26 with CfL)
   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-0.0474 | -0.1486 | -0.2931 |  -0.0358 | -0.0397 | -0.0127 |    -0.1162

Change-Id: I9e34af0fe5961ce8dbe70cb80aea2a16221d0d92

Adds a separate scale numerator for resize and superres scaling on
keyframes. They will only use this factor in their respective FIXED
modes.

Change-Id: I4ef9a5760a5423ec632d644e6c7fec674bbb46f4

Change-Id: If93f9e41c25a5885b5927e66a298c129bb844e18

This patch implements the post-encode and post-decode upscaling for the
frame superresolution experiment to work.

Upscaling happens after cdef and before loop restoration.

For now, this patch forces on random-superres.

The patch also cleans up some broken rate control hooks from VP9
days, to be brought back later when the resize and superres tools
are stable.

Change-Id: If0a8f69224dfaa0f4ae7703bd429ea2af953c7a6

Refactoring: split prediction+extension for each plane, so we can
handle luma/chroma supertx pred in different ways.
Compatibility fix: fix conflicts with cb4x4 and chroma_sub8x8, now
for chroma sub8x8 supertx, only the top-left(basic cb4x4) or the
the bottom-right(cb4x4 + chroma_sub8x8) predictor will be used
without any blending within a 8x8 unit.

Change-Id: I6cf7b12768a82d3c7e01811ada02de84af9bd8ac

Check the availability of the reference frames at the frame level at
both encoder and decoder, and if a reference frame is not available
for a specific video frame, remove the signaling of such reference
frame info at the block level.

This patch adds the consideration of the bit saving inside the RD
optimization loop.

Change-Id: I4c22f1b843b21c7d2b47e118c99c3ad615a3d4e4

Change-Id: I3ce09c03d4306c1f2a9c70aa1e82126493bc9406

This change does not impact the bitstream
  PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
0.0000 |  0.0000 |  0.0000 |   0.0000 | 0.0000 |  0.0000 |     0.0000

Change-Id: I6e131e91bad5efa345ed2542ae970eb6122eff51

Change-Id: Ideaeb52dbaf87e5a68da90cb94b0517760cb9d5c

Update and capture the effective transform block size per color
plane.

Change-Id: Ib6e0e7abb3973db6b8d511ee7c9948aaab048788

Urvang Joshi authored May 31, 2017 and James Zern committed Jun 01, 2017

Change-Id: Id2be191fb48ed8d65b452499e1a1a1f470359321

Make the txfm_above and txfm_left be processed in the unit of
miniumum transform block size. Scale the transform block step
size with respect to the mode_info step size.

Change-Id: Iee4421e005db742cd4ff7899215560063e5f68e5

This fixes an issue with context clearing introduced by commit
5e81643d.

In av1_zero_above_context width_y went from being assigned "2 *
aligned_width" to "width << 1". All this patch does is replace width
with the aligned_width.

This resolves an issue with random resizing being broken on the master
branch.

Change-Id: Ib60bf81e6091802053a5a26057c626d4efe6497c

Change-Id: I904283119d8f2c1099e6ec2953ea1c10c5e3b280

This patch forces DAALA_EC on by default and removes the dkbool coder.

Change-Id: Icd2ff08efd7bf467adf554344111473cb357adf8

All matrices are derived by subsampling 32x32 and 32x16 matrices.
Inter and intra matrices now use the same matrix set.

BUG=aomedia:520

AWCY results for default setting (qm-min=5, qm-max=9):

  PSNR  | PSNR Cb | PSNR Cr | PSNR HVS | SSIM  | MS SSIM | CIEDE 2000
   2.75 |  7.98   |    -    |  -3.52   |  0.73 |   -2.21 |   4.22

Change-Id: I8414d19eaf50cfe80d4fe2290da6cdf4ebb406cb

Properly reset mi_row and mi_col values per plane.

Change-Id: Ic624f286c8ee2521403557bc1d685752166b1947

Currently the "transform units" used to measure transform sizes
in some parts of the code are based on the smallest defined
transform size.

cb4x4 currently defines a 2x2 transform size, even when chroma_2x2
is not enabled, which means that the scale of the transform units
was always double that of MODEINFO units.

Several areas of the code were hard-coding this assumption instead
of converting from one to the other using appropriate constants.

Change-Id: Ibc55671aa5bc3ad272cb8a036f9c4f9621df85ab

Clear the clang warnings when var-tx is enabled.

Change-Id: I6b005124159b0607ec3284cc2e5ba287745a2541

Change-Id: Ia0eb3a3694fdbe9d33548ff4014b704b2f3db86a

Before this commit set_frame_size decided on the frame size to use and
then set it. It has been changed to just take an arbitrary size to make
it more flexible.

The decision of what size to use has been moved to the new
set_scaled_size and existing av1_calculate_superres_size.

setup_frame_size implements the old logic of getting the scaled size,
then superres size, then setting the frame to use it.

This change will make post-encode upscaling possible using
set_frame_size since it can now be given a target resolution.

Change-Id: I2f0f20740a54f751bc9963f279d6bcfdfb2722c2

Change-Id: I2ad15784cbc238fa4b0f993bfa64c06591ece5e9

Change-Id: I96e386678f6227f3ca735c9be2725cb9795b3296

Prep work for changing how frame contexts are signaled.

Change-Id: I0db8ec631fc2d616d16fabaf72eac5663ffe3630

The coding gain from this experiment can be mostly obtained
from ec-adapt.

BUG=aomedia:450

Change-Id: Ia7f9df9b2c13d8cdb962eeb39624f3e4e3f036ba

Properly account for the intra boundary condition for sub8x8
chroma components in the modified chroma-2x2 framework. This fixes
a rare enc/dec mismatch issue when chroma-sub8x8 is turned on.

Change-Id: I058a2fb855a491bf604277f4c82169c1b55424fa

The frame superresolution experiment currently makes no use of the
features of the loop restoration experiment. While this is planned for
the future, there is no reason to continue having frame superresolution
depend on loop restoration for now.

Frame superresolution was made dependent by having every preproccesor if
containing its config flag also depend on the loop restoration config
flag. Those if's are modified to only check the frame superresolution
flag by this patch.

Change-Id: Ieef47de29125af8d080739ffeac5c55a1fa99e23

There was a bug caused by the following sequence of events:
* A frame was coded full-size, filling out the
  cm->above_context array as normal.
* The next frame was coded at a reduced size
* Due to changes between VP9 and AV1, we now clear the
  context arrays per-tile on the decoder side. The amount
  cleared is the span of the tile, rounded up to the next
  mi unit. Since this frame is at a reduced size, this
  leaves some entries "off the edge of the frame" set to 1.
* get_entropy_context() reads a full transform block's worth
  of data from cm->above_context. This could read the off-frame
  1s, even when all the in-frame values were 0 (eg, because
  we're working on the topmost block of the frame).
* This leads to the decoder getting the wrong context, causing
  an encode/decode mismatch.

We fix this by rounding up to the next superblock, rather than
the next mi unit, when clearing the context arrays per-tile.
This is safe because all tiles other than the rightmost column
must be an integer number of superblocks wide.

BUG=aomedia:481

Change-Id: I8283c69957900572d44eb8d7f633cb59e352da3c

Offset the buffer pointers of sub8x8 chroma components to support
the coding process at bottom right 8x8 block.

Change-Id: Ide17ee31ce064484371194cbbade88603d114a2e

Loads the stored reconstructed luma pixels for each trasnform block
inside a prediction block. Supports 4:4:4 and 4:2:0 chroma subsampling
modes.

The CFL_CTX struct is now in cfl.h with appropriate forward declarations

Change-Id: I44c117899414a10a8318d14ecaed402f803de97d

BUG=aomedia:442

Change-Id: Ic5e4bb170ab7fd68355008cc4155e1a8910f344e

Process the sub8x8 chroma component at the bottom-right 8x8 block.

Change-Id: I193f8cf2d6bdabb57983cbc66fe9722e5b396207

Stores the reconstructed luma pixels for each transform block inside a
prediction block. Rectangular transform blocks are supported.

As for RDO, after all the modes have been tested for luma, an extra
encoding is perform in order to store the reconstructed pixel values of
the best mode. These values are then used for RDO on the chromatic
planes.

Change-Id: I354d9827e32fd41065f1b2ce02832d943a6fa156

This is the second patch.
* Add delta loop filter level at super block level.
* Add symbol coding for delta lf syntax
* Allow delta lf to work with segments

Change-Id: I393a021a875d03c6e113127cbb3543fc077308e4

BUG=aomedia:448

Change-Id: Ieff977fca8a5033ddef2871a194870f59301ad8f

Adds the CfL experiment flag and computes a block-level DC_PRED that is
required by CfL in order to compute alpha_cb and alpha_cr.

The rate-distorsion impact of computing DC_PRED at the prediction block level
for chroma planes is rather small

Subset 1:
master_no_cdef@2017-04-18T20:37:05.712Z
  -> block_DCPRED_no_cdef@2017-04-18T20:38:07.381
  PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
0.0712 |  0.0337 | -0.1692 |   0.0693 | 0.0814 |  0.0710 |    -0.0063
Note: CDEF was disabled because of problematic asserts.

Change-Id: I44d1cde8605b108366f4bd4cedbf5159dbbb5880