tree 601ba3f54330541e4b6e179c82dcb4e059099aa6
parent 03ea5226b1885201d5e7a139a41ee2aa4766c9fb
author Hui Su <huisu@google.com> 1523572422 -0700
committer Hui Su <huisu@google.com> 1523933764 +0000

Use more localized stats for ref frame candidate pruning

For the mode_pruning_based_on_two_pass_partition_search speed feature,
collect mode decision stats for every 32x32 block in the first pass of
parition search pass, and use the stats to prune modes in the
corresponding regions.

Currently the pruning is only applied to reference frames; the pruning
strategy is to skip reference frames that have not been selected in the
first parition search pass.

This only affects speed >= 1.

Compression loss on lowres and midres(30 frames) is about 0.1%.
Encoding speed gains on some cif sequences with QP = 30:
cheer_cif:        6.4%
city_cif:         9.4%
coastguard_cif:  16.3%
container_cif:    9.0%
crew_cif:        11.3%
average:         10.5%

Change-Id: I31211f16cbe639d2230babc21870d7ac54ca9a89