tree 8eb405642856debaf8c4827e7b5a64c1f3bd7a2e
parent eaf9d3dfbd4820f6e7d77825cc59feeafda31fe6
author Matt Wolenetz <wolenetz@chromium.org> 1549049280 +0000
committer Matthew Wolenetz <wolenetz@chromium.org> 1549049280 +0000

To M73: MSE: Reduce amount of frame flushing for common ByPts scenario

Previously, when buffering by PTS, almost all audio frames emitted by
FrameProcessor would be emitted singly, incurring significant overhead
of frequent SourceBufferStream::Append() calls of single frames versus
collections of frames, even when these audio frames really are
continuous.

This change allows the duration of the current frame to be used as a
proxy for (roughly) half of the SourceBufferStream's buffering fudge
room, with the other half already built into the FrameProcessor's
MseTrackBuffer highest_presentation_timestamp(). Because
SourceBufferStream updates its (non-decreasing) fudge room at the start
of Append() servicing, this relaxation in FrameProcessor should not
introduce failures in adjacency checks during SBS::Append() (and
underlying SourceBufferRangeByPts) processing, while allowing simple
continuous-in-DTS (within MSE coded frame processing spec'ed adjacency
logic) and continuous-in-PTS (within our SourceBufferStream's fudge
room) keyframes to not be unduly Appended one-at-at-time to
SourceBufferStream. Note, this change is not specific to audio frames;
video keyframes also satisfying such continuity are also queued for bulk
flushing later in FrameProcessor.

Relevant unit tests now verify the specifics of group start signalling
and the sequence of append calls by FrameProcessor.

BUG=879970,912695
TEST=Multiple updated and new FrameProcessorTests

Change-Id: Ifcfe9fc2062888b1c835380871be355a45b0babe
Reviewed-on: https://chromium-review.googlesource.com/c/1441492
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Matthew Wolenetz <wolenetz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#627070}(cherry picked from commit d2ad5ce3165b485156ffff771a3e860b1ab78ad4)

TBR=sandersd@chromium.org

Change-Id: I37f2fa8abe0bc54bca5eb0c248a4d2bed7115769
Reviewed-on: https://chromium-review.googlesource.com/c/1450439
Reviewed-by: Matthew Wolenetz <wolenetz@chromium.org>
Cr-Commit-Position: refs/branch-heads/3683@{#130}
Cr-Branched-From: e51029943e0a38dd794b73caaf6373d5496ae783-refs/heads/master@{#625896}