This class looks first and foremost on frame intervals instead of
number of frames withing the averaging window. This leads to higher
prevision values than the bucketized methods of RateTracker and
RateStatistics.
It is also design to return floating point values, for cases where we
are running at low fps - such as a somewhat common 30/4 = 7.5fps.
Bug: webrtc:10481
Change-Id: I41c36caaf2b7b46edf7927c8dd08e6cde3380884
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/148593
Reviewed-by: Magnus Flodman <mflodman@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28857}
