This patch added two features to improve entropy coding efficiency
for coefficient tokens.
1. Choose 1 of 4 default probability tables based on q-index for
key-frames.
It is ported from nextgen branch:
https://chromium-review.googlesource.com/#/c/280586/
2. Do backward update after each superblock (64X64) row using
subframe token counts.
Coding gain: 0.1% on lowres; 0.42% on midres; 0.36% on hdres.
Much larger gain for key-frames: 2.6%, 2.3%, 1.7%.
Design doc: go/huisu-entropy
Change-Id: Ia3b6a615636be09247d70e4c520405637561532b
Brings the following commits to vp10:
269428e Tie the bit cost scale to a define.
d13385c Switch to 9-bit rate cost constants built on a 256 probability denominator.
ad43a73 Fix a signed overflow in vp9 motion cost.
1c9b091 Fix some interger overflow errors
fac947d Restore previous motion search bit-error scale.
Change-Id: I598ba7ee7efcde18439c31dfa96b86cbf297a580
The nominal tx_type for a given mode is used as a context
to encode the actual tx_type for intra.
Results:
derflr: -0.241% BDRATE
hevcmr: -0.366% BDRATE
Change-Id: Icfe7b0a58d79bc6497a06e3441779afec6e01e21
Remove MISC_FIXES flags except for the changes on MV precision, which
has a 0.1% performance drop.
On derflr, the impact is -0.012%.
Change-Id: I0a74e5a212dd0cb827192a318c92a714c9681e45
Remove delta index 254 from probability remapping and subexp coding.
Saves 1-bit when the delta index is 129.
Change-Id: I88aba565fc766b1769165be458d2efd3ce45817e
Does not include DST1 yet.
derflr: +1.437 (8-bit internal), +7.243 (12-bit internal)
with --enable-ext-tx
Change-Id: I91f1759fd2de794755eb6384cda52e80e979cb7d
