tree 79c1c76d424db1cd3e71ac989852df770bd80387
parent 7123b669009331ca3a774338eeaeb09c03cbc1ca
author Paul Wilkins <paulwilkins@google.com> 1608038473 +0000
committer Paul Wilkins <paulwilkins@google.com> 1610465586 +0000

Further tweaks to rate adaption.

This is a further experimental change to the rate adaptation.
The rate error factor is based on the bits off target error
measured against the larger of the actual bits used so far and
the projected number of bits left. This tends to naturally damp
the factor so that it is likely to be less extreme at the two ends
of the clip.

A larger adjustment is allowed at the end of the first GOP.
The specified undershoot and overshoot limits are used to
define the maximum amount of adjustment allowed.

This gives a small improvement in average psnr and vmaf scores
but a  small drop in ssim.  However, the average absolute
rate error improves by almost 2%.

STATS_CHANGED

Change-Id: Ia7d2bc833a4266ec92e9c4e78caa4d80ed72f3af