This patch alters the balance of context between the
coefficient bands (reflecting the position of coefficients
within a transform blocks) and the energy of the previous
token (or tokens) within a block.

In this case the number of coefficient bands is reduced
but more previous token energy bands are supported.

Some initial rebalancing of the default tables has been
by running multiple derf clips at multiple data rates using
the ENTOPY_STATS macro. Further balancing needs to be
done using larger image formatsd especially in regard to
the bigger transform sizes which are not as well represented
in encodings of smaller image formats.

Change-Id: If9736e95c391e711b04aef6393d26f60f36e1f8a

The commit added a final rounding choice for 8x8 forward dct to get
rid of a sign bias at DC position and improve the accuracry in term
of round trip error for 8x8 fDCT/iDCT.

This commit also enabled forward 8x8 dct test.

Change-Id: Ib67f99b0a24d513e230c7812bc04569d472fdc50

Removing redundant 'extern' keywords and parentheses, fixing indentation,
making variable names lower case, using short expressions x *= c
instead of x = x * c, minor code simplifications.

Change-Id: If6a25fcf306d1db26e90d27e3c24a32735c607de

1. changed 4x4 test name to Vp9Fdct4x4Test to be consistent
2. remove forward 8x8 dct test code from idct8x8_test.cc
3. temporarily disable other forward dct tests to allow fdct work in
progress

Change-Id: I566aeed9c7c34da5a206190aa7d0e847a4008b36

The over quant code was added in VP8 post
bitstream freeze to allow compression to lower
data rates

In VP9 the real qualtizer range has been greatly
extended anyway.

Change-Id: I5d384fa5e9a83ef75a3df34ee30627bd21901526

This patch includes 4x4, 8x8, and 16x16 forward butterfly ADST/DCT
hybrid transform. The kernel of 4x4 ADST is sin((2k+1)*(n+1)/(2N+1)).
The kernel of 8x8/16x16 ADST is of the form sin((2k+1)*(2n+1)/4N).

Change-Id: I8f1ab3843ce32eb287ab766f92e0611e1c5cb4c1

Removing redundant 'extern' keywords. Moving VP9DX_BOOL_DECODER from .h
to .c file.

Change-Id: I5a3056cb3d33db7ed3c3f4629675aa8e21014e66

Allows the user to specify whether decode errors should be fatal or not.
Also makes mismatches optionally fatal.

Change-Id: I58cff4a82f3d42f5653b91cf348a7f669377e632

Removing redundant 'extern' keyword from function declarations and making
function arguments lower case.

Change-Id: Idae9a2183b067f2b6c85ad84738d275e8bbff9d9

The information is a duplicate of "eob" in BLOCKD.

Change-Id: Ia6416273bd004611da801e4bfa6e2d328d6f02a3

Refactors the switchable filter search in the rd loop to
improve encode speed.

Uses a piecewise approximation to a closed form expression to estimate
rd cost for a Laplacian source with a given variance and quantization
step-size.

About 40% encode time reduction is achieved.

Results (on a feb 12 baseline) show a slight drop:

derf: -0.019%
yt: +0.010%
std-hd: -0.162%
hd: -0.050%

Change-Id: Ie861badf5bba1e3b1052e29a0ef1b7e256edbcd0

The issue that potentially broke the encoding process was due to the fact
that the length of token link is calculated from the total number of tokens
coded, while it is possible, in high bit-rate setting, this length is
greater than the buffer length initially assigned to the cpi->tok.

This patch increases the initially allocated buffer length assigned to
cpi->tok from
(mb_rows * mb_cols * 24 * 16) to (mb_rows * mb_cols * (1 + 24 * 16)).

It resolves the buffer overflow problem.

Change-Id: I8661a8d39ea0a3c24303e3f71a170787a1d5b1df

Change-Id: I7c6e3bebd94856b24dbe2aded7f9e04ef8bb8c08

Change-Id: I7b7b8d4fda3a23699e0c920d727f8c15d37d43aa

Fixes to make Entropy stats code work again

Change-Id: I62e380481a4eb4c170076ac6ab36f0c2b203e914

- Using multiplication and shifting instead of division in
  intra prediction.
- Maximum absolute difference is 1 for division statements
  in d45, d27, d63 prediction modes. However, errors can
  cumulate for large block sizes when using already predicted
  values.
- Maximum number of non-matching result values in loops using
  division are:
  4x4        0/16
  8x8        0/64
  16x16     10/256
  32x32     13/1024
  64x64    122/4096

  Overall PSNR
  derf:     0.005
  yt:      -0.022
  std-hd:   0.021
  hd:      -0.006

Change-Id: I3979a02eb6351636442c1af1e23d6c4e6ec1d01d

The issue was caused by a out-of-order merge, which leads to wrong
functions are called at lossless mode.

Change-Id: If157729abab62954c729e0377e7f53edb7db22ca

rebased.

This patch includes 16x16 butterfly inverse ADST/DCT hybrid
transform. It uses the variant ADST of kernel
    sin((2k+1)*(2n+1)/4N),
which allows a butterfly implementation.

The coding gains as compared to DCT 16x16 are about 0.1% for
both derf and std-hd. It is noteworthy that for std-hd sets
many sequences gains about 0.5%, some 0.2%. There are also few
points that provides -1% to -3% performance. Hence the average
goes to about 0.1%.

Change-Id: Ie80ac84cf403390f6e5d282caa58723739e5ec17

The commit changes the coding mode to lossless whenever the lowest
quantizer is choosen.

As expected, test results showed no difference for cif and std-hd
set where Q0 is rarely used. For yt and yt-hd set, Q0 is used for
a number of clips, where this commit helped a lot in the high end.

Average over all clips in the sets:
yt: 2.391% 1.017% 1.066%
hd: 1.937%  .764%  .787%

Change-Id: I9fa9df8646fd70cb09ffe9e4202b86b67da16765

Change-Id: I13d8ae754827368755575dd699a087b3b11f5b16

The 32x32 value in case of splitmv was uninitialized. this leads to
all kind of erratic behaviour down the line. Also fill in dummy values
for superblocks in keyframes (the values are currently unused, but we
run into integer overflows anyway, which makes detecting bad cases
harder). Lastly, in case we did not find any RD value at all, don't
set tx_diff to INT_MIN, but instead set it to zero (since if we couldn't
find a mode, it's unlikely that any particular transform would have made
that worse or better; rather, it's likely equally bad for all tx_sizes).

Change-Id: If236fd3aa2037e5b398d03f3b1978fbbc5ce740e

This issue breaks the encoding process of the codebase. The effect
emerges only in particular test sequence at certain bit-rates and
frame limits.

Change-Id: I02e080f2a49624eef9a21c424053dc2a1d902452