tree e14d0a4dd3d6bcb41d1ddcfe65d6a574731f95a7
parent d8d5288e57af64c3cc8ab4cfe5c5a6c4c0a2a3a4
author Yunqing Wang <yunqingwang@google.com> 1571081041 -0700
committer Yunqing Wang <yunqingwang@google.com> 1571081041 -0700

Remove 1 speed level in encoder

For good mode encoding, now we have 6 speed levels(speed 0 to speed 5).
Quality compression:
speed 4 vs speed 3:
  PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
1.7519 |  1.7049 |  0.7850 |   1.6157 | 1.7632 |  1.6643 |     1.7089
https://arewecompressedyet.com/?job=av1-10-11-2019-sp3%402019-10-11T18%3A32%3A18.117Z&job=av1-10-11-2019-sp4%402019-10-11T18%3A32%3A40.776Z

speed 5 vs speed 4:
  PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
1.5877 |  1.2300 |  1.3265 |   1.6366 | 1.6963 |  1.7104 |     1.5932
https://arewecompressedyet.com/?job=av1-10-11-2019-sp4%402019-10-11T18%3A32%3A40.776Z&job=av1-10-11-2019-sp5%402019-10-11T18%3A33%3A02.178Z

The quality & speed gaps among speed 3, 4, 5 are small comparing to
other speeds. This patch removed speed 4, and made speed 5 to be the
new speed 4.

STATS_CHANGED

Change-Id: Ia7f95e9ba478e743cf0301030c456f7791a2d3a1