tree f99244e32bd6e5e64b16cbaf9c2ed141118cbf28
parent 80b1bb6daa1d7fb5890f19707289b9ffb518dff0
author Urvang Joshi <urvang@google.com> 1561070181 -0700
committer Urvang Joshi <urvang@google.com> 1564800928 +0000

Recode loops for both superres and fullres.

This combined recode loop is used in SUPERRES_AUTO mode to find the
better out of the two as per RDCOST.

It is enabled for VBR and CQ modes, for video (non-image) coding.

Note that we need to save / restore the some extra info between encodes
for this, related to filtering and rate control.

Also, for frames where superres is enabled, we force denom to be at
least 9 in superres pass, so that both fullres and superres are tried
in the recode loop.

BDRate (PSNR) improvement for hdres set at low target bitrates:

(i) SUPERRES_AUTO mode (before vs after):
Overall: -1.79%
- station2_1080p25.y4m      -13.974
- stockholm_ter_720p60.y4m  -6.350
- mobcal_720p50.y4m         -6.182
- old_town_cross_720p50.y4m -5.631
- city_720p30.y4m           -4.297
- johnny_720p60.y4m         -4.089
- rush_hour_1080p25.y4m     -4.042
- shields_720p50.y4m        -3.384

(ii) fullres vs SUPERRES_AUTO (after):
Overall: -0.187
- shields_720p50.y4m:          -3.117
- factory_1080p30.y4m:         -1.640
- cyclists_720p30.y4m:         -1.564
- mobcal_720p50.y4m:           -1.413
- sheriff_720p30.y4m:          -1.311
- basketballdrive_1080p50.y4m: -0.739
- stockholm_ter_720p60.y4m:    -0.723

STATS_CHANGED for SUPERRES_AUTO mode

Change-Id: I4dd984f35f68d80409d1f53083eda00e257c1706