Optimized 2 up-sampled reference prediction functions in high-bit
depth case. This reduced the HBD encoding time by 3%.
Change-Id: I8663ffb5234f5e70168c0fc9ca676309fe8e98f2
Using the up-sampled reference frames in sub-pixel motion search is
enabled as a speed feature for good-quality mode speed 0 and speed 1.
Change-Id: Ieb454bf8c646ddb99e87bd64c8e74dbd78d84a50
Up-sampled the reference frames to 8 times in each dimension using
the 8-tap interpolation filter. In sub-pixel motion search, use the
up-sampled reference frames to find the best matching blocks. This
largely improved the motion search precision, and thus, improved
the compression quality. There was no change in decoder side.
Borg test and speed test results:
1. On derflr set,
Overall PSNR gain: 1.306%, and SSIM gain: 1.512%.
Average speed loss on derf set was 6.0%.
2. On stdhd set,
Overall PSNR gain: 0.754%, and SSIM gain: 0.814%.
On hevchd set,
Overall PSNR gain: 0.465%, and SSIM gain: 0.527%.
Speed loss on HD clips was 3.5%.
Change-Id: I300ebaafff57e88914f3dedc8784cb21d316b04f
This commit unifies the motion vector cost buffers for full pixel
and sub-pixel motion search. The new motion vector coding system
provides 0.5% coding gains for 720p and above sequences and 0.2%
for lower resolution sets.
Change-Id: I927ec81eadc39d11a3c12b375221a1ddd2e8bf24
Brings the following commits to vp10:
269428e Tie the bit cost scale to a define.
d13385c Switch to 9-bit rate cost constants built on a 256 probability denominator.
ad43a73 Fix a signed overflow in vp9 motion cost.
1c9b091 Fix some interger overflow errors
fac947d Restore previous motion search bit-error scale.
Change-Id: I598ba7ee7efcde18439c31dfa96b86cbf297a580
This change has been imported from VP9 and
alters the nature and use of exhaustive motion search.
Firstly any exhaustive search is preceded by a normal step search.
The exhaustive search is only carried out if the distortion resulting
from the step search is above a threshold value.
Secondly the simple +/- 64 exhaustive search is replaced by a
multi stage mesh based search where each stage has a range
and step/interval size. Subsequent stages use the best position from
the previous stage as the center of the search but use a reduced range
and interval size.
For example:
stage 1: Range +/- 64 interval 4
stage 2: Range +/- 32 interval 2
stage 3: Range +/- 15 interval 1
This process, especially when it follows on from a normal step
search, has shown itself to be almost as effective as a full range
exhaustive search with step 1 but greatly lowers the computational
complexity such that it can be used in some cases for speeds 0-2.
This patch also removes a double exhaustive search for sub 8x8 blocks
which also contained a bug (the two searches used different distortion
metrics).
For best quality in my test animation sequence this patch has almost
no impact on quality but improves encode speed by more than 5X.
Restricted use in good quality speeds 0-2 yields significant quality gains
on the animation test of 0.2 - 0.5 db with only a small impact on encode
speed. On most natural video clips, however, where the step search
is performing well, the quality gain and speed impact are small.
Change-Id: Iac24152ae239f42a246f39ee5f00fe62d193cb98
