tree b9550caedff33aaa2e39cf1c9f154742fbd0ee33
parent b5bc488aed0118b56f9d3b9f8b53baa6b5b4c2fd
author Paul Wilkins <paulwilkins@google.com> 1583171167 +0000
committer Paul Wilkins <paulwilkins@google.com> 1584640807 +0000

Added alternate bit allocation method.

Added an alternate algorithm for distributing bits over ARFs.
This is based on a fixed distribution pattern and ratio of bits
allocated.

Also added stats to record the actual Q used at different
levels in the coding pyramid. In tests with strict rate control
this proved to be a good baseline for the lowest allowed Q
for the next level.

All features disabled by default for now so there should be no
stats change for this patch.

Enabling FIXED_ARF_BITS Has a surprisingly modest impact
on metrics.

Enabling STRICT_RC on its own gives quite accurate rate control but
a huge hit to metrics.

Enabling STRICT_RC with FIXED_ARF_BITS and ALT_ARF_ALLOCATION
give accurate rate control with a greatly reduced metrics penalty.
For example at 100 Kbits Akiyo is about 1db better with all enabled than
with only STRICT_RC.

If strict RC is only applied to best quality the metrics are better but rate
control worse for those clips that tend to overshoot. Finding an alternative
way to select an appropriate worst quality at each level is TBD.

Change-Id: I402773c5e5a36a8417f8b38f8ef536d37dc98ac0