tree ae1878f3ac4b787167e83f8b2a0d709388fa63aa
parent 34b591fa20e5687275efa540c169b02a499dff28
author chiyotsai <chiyotsai@google.com> 1593037930 -0700
committer Chi Yo Tsai <chiyotsai@google.com> 1593124263 +0000

Remove calls to atan in generate_hog

This CL replaces calls to atan in generate_hog with a llok up table to
find the histogram bin index.

There is a small encoding difference due to the new rounding rules, but
the difference is on the order of 0.001%.

Performance on Speed 6:
 FRAME_TYPE | TESTSET |  SPD
            |   HDRES | +2.0%
    INTRA   |  MIDRES | +1.6%
            |  LOWRES | +1.2%
------------+---------+--------
            |   HDRES | +0.6%
    INTER   |  MIDRES | +0.4%
            |  LOWRES | +0.3%

STATS_CHANGE

Change-Id: I50bdd93040c5f00929a846005c3c34d9a77f2923