This patch adds bit account infrastructure to the bit reader API.
When configured with --enable-accounting, every bit reader API
function records the number of bits necessary to decoding a symbol.
Accounting symbol entries are collected in global accounting data
structure, that can be used to understand exactly where bits are
spent (http://aomanalyzer.org). The data structure is cleared and
reused each frame to reduce memory usage. When configured without
--enable-accounting, bit accounting does not incur any runtime
overhead.

All aom_read_xxx functions now have an additional string parameter
that specifies the symbol name. By default, the ACCT_STR macro is
used (which expands to __func__). For more precise accounting,
these should be replaced with more descriptive names.

Change-Id: Ia2e1343cb842c9391b12b77272587dfbe307a56d

Merge "Adds ability to measure with a higher precision the number of bits read per symbol." into nextgenv2

Move computing the segmentation_probs.tree_cdf table per symbol to
 computing it only when the probabilities are updated.

Change-Id: I3826418094bbaca4ded87de5ff04d4b27c85e35a

read per symbol.

Change-Id: I218abaa5172b769b66dba45050381c0212602668

This fixes mismatches due to overflowing low precision parameters.

Change-Id: If34e39ca7ab0adc9688d46b0e8ed62cbb6fdaff0

Change-Id: I1b41146ae844c985566f5f9fdaeb5d4a4a5927b6

Ransac's get_rand_indices originally used rand_r seeded with the
same value every time, producing the same random sequence at every
iteration. This causes the global motion parameters to be slightly
less accurate because ransac cannot improve the model fit after
the first attempt.

Change-Id: Idca2f88468ea21d19ba41ab66e5a2744ee33aade

This function is called after `super_block_yrd` and assumes that the dst
buffer is correct but that is no longer always the case after
daf841b4 since we don't call
`txfm_rd_in_plane` after the RDO loop in `choose_tx_size_from_rd`.
We could fix this by always saving and restoring the dst buffer but
removing `rd_variance_adjustment` is a better solution:
- Getting the dst buffer always right is tricky as demonstrated by the
  fact that it is wrong now, even if we fix it now we could break it later
  and not notice
- Perceptual weighting is a good idea but `rd_variance_adjustment` is the
  wrong approach as it weights both the rate and the distortion:
  to get meaningful units you should only weight the distortion,
  weighting rate means that we pretend some bits cost less than other
  bits, this is not the case. The distortion weighting approach is
  implemented by Daala in `od_compute_dist` and we plan to experiment
  with this in AV1 too.
- Removing `rd_variance_adjustment` improves coding efficiency on all
  metrics, here are the results for objective-1-fast using the Low
  Latency settings:

      PSNR Y:     -0.14%
     PSNRHVS:     -0.17%
        SSIM:     -0.12%
      MSSSIM:     -0.12%
   CIEDE2000:     -0.07%

Change-Id: I74b26b568ee65f56521646b8f30dd53bcd29fce3

Experiment on coding block at resolution of 4x4 block.

Change-Id: I6aa201038f00c590747d800edb0a3e76ab1a51e8

Change-Id: Ibc73b4066dcdee45d32355144124762d26a16a28

This array was allocated and used to save and restore segmentation map,
however the original segmentation map was never modified between the
calls to save and restore.

Change-Id: Iaf0fbfed733c097e84cf44d2aa6b8f35d2fb456b

Change-Id: Ifcc329df240c0771172180933a6180b21fd31abe

This is not used since the commint 00cd5de5,
"Remove skip_recode speed feature".

Change-Id: Ic03da6c0095f6285a3889d5d22e8aaa2e6cbfd79

On average no compression performance changes. Encoding speed is
increased by 10~20% on some test clips in the derf set.

Change-Id: I9856caaa260303f6f6259686671bed7d51012277

Drop some speed features used in speed 2 and above, during the
algorithm development process. This helps simplify the codebase.

Change-Id: I3b2f5560d90b00d2d8fd57c2cb36f6ddd3f228e4

Change-Id: I65c04006f6e6eb13ceb22efc1c39915cb3c82b82

Change-Id: Ic11eae36c9c62a20699197847aa3ef9562d4ad7e

Change-Id: Ie90dd06c387119ccd9c920a328c942477df00bb7

This commit ports the following from aom/master:
4c462788 Add aom_reader_tell() support.
b9c99350 Remove an erroneous declaration.
56c9c3bf Fix ANS build.

Change-Id: I59bd910f58c218c649a1de2a7b5fae0397e13cb1

This computation should match the code in encode_block
to increase the accuracy of the rd optimization.

Change-Id: Ibc9d9ab6d88d0c0f3af62e9cc233216aba48a57e

When built with var_tx and ext_tx, select_tx_size_fix_type is used
to compute the cost for using a particular tx_type.
The code indexes the array inter_tx_type_costs at the wrong location
resulting in a zero cost for signalling tx_type for rect_tx blocks.

Change-Id: Iba38be3a0d822109f778f0600b242dfb40359766

Change-Id: I33899eca44300037816c9f20c965aa8311a1ef52

Change-Id: I35f85bad88c637cea62577c546cdd5ced0e21bd6