media: Fix WebM keyframe detection in BlockGroup

media: Fix WebM keyframe detection in BlockGroup

The right way to detect the presence of a keyframe in a BlockGroup
is to look for the absence of the ReferenceBlock element [1].

TEST=new pipeline integration test
BUG=397073
[1] https://matroska.org/technical/specs/index.html#ReferenceBlock

Committed: https://crrev.com/f5f6998f2f5db240fac1c92c93a76bdae3cb611b
Cr-Commit-Position: refs/heads/master@{#393078}

[vignesh, 2016-05-10 16:29:44]

vigneshv@chromium.org changed reviewers:
+ chcunningham@chromium.org, fgalligan@chromium.org, wolenetz@chromium.org

[vignesh, 2016-05-10 16:29:45]

I have also verified this manually by passing a BlockGroup wrapped VP9 file
through MSE (it fails to play before this patch as it can never find a
keyframe).

[chcunningham, 2016-05-10 19:28:36]

lgtm % test question.

Vignesh/Matt, wdyt about unit vs integration test here (why not both?). I think
BlockInfo and VerifyBuffers could easily take on the role of verifying key frame
expectations.

[vignesh, 2016-05-11 16:24:15]

> 
> Vignesh/Matt, wdyt about unit vs integration test here (why not both?). I
think
> BlockInfo and VerifyBuffers could easily take on the role of verifying key
frame
> expectations.

I thought about it, but skipped it since there was no existing keyframe
verification in place. I'll add it.

[vignesh, 2016-05-11 18:14:14]

Have added the unit tests. PTAL.

[chcunningham, 2016-05-11 20:18:40]

On 2016/05/11 18:14:14, vignesh wrote:
> Have added the unit tests. PTAL.

LGTM. Thanks Vignesh!

[vignesh, 2016-05-11 20:20:27]

The CQ bit was checked by vigneshv@chromium.org

[commit-bot: I haz the power, 2016-05-11 20:20:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1966673002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1966673002/20001

[commit-bot: I haz the power, 2016-05-11 21:54:39]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-05-11 21:56:55]

Description was changed from

==========
media: Fix WebM keyframe detection in BlockGroup

The right way to detect the presence of a keyframe in a BlockGroup
is to look for the absence of the ReferenceBlock element [1].

TEST=new pipeline integration test
BUG=397073

[1] https://matroska.org/technical/specs/index.html#ReferenceBlock
==========

to

==========
media: Fix WebM keyframe detection in BlockGroup

The right way to detect the presence of a keyframe in a BlockGroup
is to look for the absence of the ReferenceBlock element [1].

TEST=new pipeline integration test
BUG=397073

[1] https://matroska.org/technical/specs/index.html#ReferenceBlock

Committed: https://crrev.com/f5f6998f2f5db240fac1c92c93a76bdae3cb611b
Cr-Commit-Position: refs/heads/master@{#393078}
==========

[commit-bot: I haz the power, 2016-05-11 21:56:56]

Patchset 2 (id:??) landed as
https://crrev.com/f5f6998f2f5db240fac1c92c93a76bdae3cb611b
Cr-Commit-Position: refs/heads/master@{#393078}

[wolenetz, 2016-05-17 19:16:55]

belated lgtm. Note that text track blocks should all be key frames, though that
is enforced later in our pipeline than the stream parser, so the unit tests
triggering parse of non-keyframe text blocks is ok. Thanks for fixing this!