tree a6f077839abe205b6bf60f3ceccc1263de1b5791
parent cb07fbadfa2f4c7ad98cdad00a1ec9d094188cf7
author Cheng Chen <chengchen@google.com> 1560970528 -0700
committer Cheng Chen <chengchen@google.com> 1562883185 +0000

Apply temporal filtering on key frames.

Apply temporal filtering on key frames, except
(1) if the key frame interval is smaller than 7.
(2) if the key frame is noise free.

Use 7 frames for filtering (actually 6, if exclude current frame).
The change is under a macro in encode_stratgey.c.

Use original non-local means method instead of the new version
applied to alt-ref frames
(https://aomedia-review.googlesource.com/c/aom/+/88481)
(This gives additional 0.42% gain on hdres).

Performance:
(1). AWCY, spd0.
   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-2.8877 | -2.7754 | -2.7226 |  -2.6934 | -2.2295 | -2.5333 |    -1.9622

(2). Google test sets, VBR, 150 frames, spd1.
          avg_psnr    ovr_psnr     ssim     vmaf
lowres      -2.87       -3.14     -3.88    -3.77
midres      -0.96       -0.99     -1.13    -0.86
hdres       -1.48       -1.64     -1.88    -2.08

(3). Google test sets, VBR, 150 frames, spd4.
          avg_psnr    ovr_psnr     ssim     vmaf
lowres      -2.80       -3.04     -3.74    -3.56
midres      -0.87       -0.91     -1.01    -0.57
hdres       -1.26       -1.46     -1.67    -1.71

(4). Google ugc360p, VBR, 150 frames, spd0.
          avg_psnr    ovr_psnr     ssim     vmaf
ugc360p     -1.18       -1.00     -1.45    -1.33

STATS_CHANGED

Change-Id: I18cd5b8a067b9e0d0f2e5bcff01daa66bb331ae7