tree 90e3856c252e9e9abac885c974fea8ffd04b08fd
parent 0bc0a1a126fe8a39ddf56776b6f40f904a9aa0ad
author linzhen <linzhen@google.com> 1663092811 +0000
committer Lin Zheng <linzhen@google.com> 1663604607 +0000

Add frame_refs_short_signaling support for rtc

This commit is to enable frame_refs_short_signaling feature for rtc low
resolution (resolution < 360p) and high speed (speed >= 9) case. In this
case, we only use LAST and GOLD ref frames, so we could
potentially save some header bits for parsing unused ref frame index,
which is frame_refs_short_signaling will do.

Note that "--enable-order-hint" is disabled in default rtc configutaions,
but enabling frame_refs_short_signaling requires "--enable-order-hint"
to be turned on. The Borg resutls below are comparing "origin/main +
--enable-order-hint=0 " vs. "this commit + --enable-order-hint=1". The
bdrate gain shows that enabling frame_refs_short_signaling not only
compensated the overhead by enabling order hint, but also provided some
extra gain.

Test set: rtc_derf
speed   avg_psnr/ovr_psnr/ssim  encoding_speedup
9       -0.209/-0.204/-0.233       +0.042
10      -0.024/-0.034/0.017        +0.005

Change-Id: I51c5bc7095f7f3fda135176b3e934d8a876fc9c5