Orientation partition pruning

[chengchen-google]

Add a new speed feature to analyze the structure orientation of the source signal to prune horz/vert partition types.

The speed feature shows a good tradeoff for speed 5.

RA performance, baseline 4a8df58:

    Speed           A1 BD-Rate (YUV)  A1 Speedup    A1 Ratio
    Speed_4         +0.16%             +1.61%       10.1
    Speed_5         +0.14%             +3.09%       22.1
    
    Speed           A2 BD-Rate (YUV)  A2 Speedup    A2 Ratio
    Speed_4         +0.19%             +2.96%       15.6
    Speed_5         +0.21%             +2.89%       13.8

STATS_CHANGED

Change-Id: Ic60b2b406662d6ab3a3803331093fd4456301833

[leolzhao]

As the loss for class A1 is relatively big and one MR #5253 about block partition speed up was just merged, please rebase the code and re-test it on top of this commit 45dc128.

[urvangjoshi]

As the loss for class A1 is relatively big and one MR #5253 about block partition speed up was just merged, please rebase the code and re-test it on top of this commit 45dc128.

Any update on this @chengchen-google ?

[yeqing-wu]

Let's run this PR on top of latest av2-enc branch, if the tradeoff cannot meet speed 4 minimum bar ratio, but >=15x for speed 5 or >=10x for speed 6, then merge them into speed 5 or speed 6 accordingly.

[chengchen-google]

As the loss for class A1 is relatively big and one MR #5253 about block partition speed up was just merged, please rebase the code and re-test it on top of this commit 45dc128.

Any update on this @chengchen-google ?

Last time I tested on top of two-pass partition, the tradeoff is reduced.
I will rebase to the most recent head and test it.
I will report results as soon as possible.

[chengchen-google]

Let's run this PR on top of latest av2-enc branch, if the tradeoff cannot meet speed 4 minimum bar ratio, but >=15x for speed 5 or >=10x for speed 6, then merge them into speed 5 or speed 6 accordingly.

I tested the PR on the most recent head: 4a8df58

The performance is:
'''

Speed Level	A1 BD-Rate (YUV)	A1 Speedup	A1 Ratio	A2 BD-Rate (YUV)	A2 Speedup	A2 Ratio
Speed 4	+0.16%	+1.61%	10.1	+0.19%	+2.96%	15.6
Speed 5	+0.14%	+3.09%	22.1	+0.21%	+2.89%	13.8
'''

I recommend to turn it on at speed 5.

[chengchen-google]

Let's run this PR on top of latest av2-enc branch, if the tradeoff cannot meet speed 4 minimum bar ratio, but >=15x for speed 5 or >=10x for speed 6, then merge them into speed 5 or speed 6 accordingly.

I tested the PR on the most recent head: 4a8df58

The performance is: '''

Speed Level A1 BD-Rate (YUV) A1 Speedup A1 Ratio A2 BD-Rate (YUV) A2 Speedup A2 Ratio
Speed 4 +0.16% +1.61% 10.1 +0.19% +2.96% 15.6
Speed 5 +0.14% +3.09% 22.1 +0.21% +2.89% 13.8
'''
I recommend to turn it on at speed 5.

In addition, the performance with a relaxed threshold on speed 6 is reported in a separate PR: #5402