tree f638c3e8a5913f9296fefb11ca680aedef655ab1
parent 79f3606b62b9c881a64a81e74b9b4e72115eda18
author Urvang Joshi <urvang@google.com> 1548721004 -0800
committer Urvang Joshi <urvang@google.com> 1548867006 +0000

enforce_max_ref_frames only when 7 refs allowed.

A command-line option was recently added to ask for a certain number of
maximum reference frames to use per frame.

We should call enforce_max_ref_frames() only when max_reference_frames
== 7, because for values < 7, we will later restrict to
max_reference_frames specified anyway.

This reduces the loss going from max_reference_frames = 7 to
max_reference_frames = 3 for speed 2 and above.

New numbers for 60 frames:
(baseline:    max_reference_frames = 7
 compared to: max_reference_frames = 3)

speed 1 (same as before this patch):
- lowres: +1.098
- midres: +1.190

speed 2:
- lowres: +1.648
- midres: +1.616

speed 3:
- lowres: +2.103
- midres: +2.477

Change-Id: Ide8c14e49f1d60280d9e6093108f72517e085162