1156668 - MSE - mochitest test for WebM on B2G failed due to MediaOmxReader::ReadMetadata run in wrong thread

Status: RESOLVED WORKSFORME

(Core :: Audio/Video, defect)

Description

[Chih-Hsuan Kuo [:tommykuo]]

The error is following:

> I/PRLog   ( 1753): -1216884640[b214a080]: WebMContainerParser(afe2fcc0:video/webm)::virtual bool mozilla::WebMContainerParser::ParseStartAndEndTimestamps(mozilla::MediaLargeByteBuffer*, int64_t&, int64_t&): Stashed init of 236 bytes.
> I/PRLog   ( 1753): -1216884640[b214a080]: MediaSourceReader(b02f6000)::already_AddRefed<mozilla::SourceBufferDecoder> mozilla::MediaSourceReader::CreateSubDecoder(const nsACString_internal&, int64_t): subdecoder afe4e880 subreader b026a000
> I/PRLog   ( 1753): -1216884640[b214a080]: MediaSourceResource(afe41830:)::virtual int64_t mozilla::MediaSourceResource::GetLength(): UNIMPLEMENTED FUNCTION at ../../../../../gecko/dom/media/mediasource/MediaSourceResource.h:49
> I/PRLog   ( 1753): -1216884640[b214a080]: MediaSourceResource(afe41830:)::virtual void mozilla::MediaSourceResource::SetPlaybackRate(uint32_t): UNIMPLEMENTED FUNCTION at ../../../../../gecko/dom/media/mediasource/MediaSourceResource.h:41
> I/PRLog   ( 1753): -1216884640[b214a080]: MediaSourceReader(b02f6000)::void mozilla::MediaSourceReader::MaybeNotifyHaveData(): isSeeking=0 haveAudio=0, haveVideo=0 ended=0
> I/PRLog   ( 1753): -1184671360[afe24580]: TrackBuffer(b02f8800:video/webm)::void mozilla::TrackBuffer::InitializeDecoder(mozilla::SourceBufferDecoder*): Initializing subdecoder afe4e880 reader b026a000
> F/MOZ_Assert( 1753): Assertion failure: OnTaskQueue(), at ../../../../../gecko/dom/media/omx/MediaOmxReader.cpp:256

When TrackBuffer start to initialize decoders, the initialization task and the task of read meta data in initialization task need different threads. So when it want to read meta data, the thread checking assert would fail.

Comment 1

[Chih-Hsuan Kuo [:tommykuo]]

Attachment: Workaround to use another thread in read meta data

I use the same workaround in WebMReader::ReadMetadata. It use the decoder thread to read meta data to avoid the wrong thread error.

See also Bug 1148234, after this bug is fixed, we won't need this workaround.

Comment 2

[Blake Wu [:bwu][:blakewu]]

Did you modify any codes to test WebM MSE on B2G?

Comment 3

[Chih-Hsuan Kuo [:tommykuo]]

I only modify the assertion to check the thread in MediaOmxReader::ReadMetadata.

Comment 4

[Blake Wu [:bwu][:blakewu]]

No need to enable some prefs in all.js or disable MOZ_FMP4 for webm?

Comment 5

[Chih-Hsuan Kuo [:tommykuo]]

(In reply to Blake Wu [:bwu][:blakewu] from comment #4)
> No need to enable some prefs in all.js or disable MOZ_FMP4 for webm?

I think the prefs are already enabled in 'prefs_general.js' for testing. So, we don't need to enable 'media.mediasource.webm.enabled' by ourself.

Comment 6

[Chih-Hsuan Kuo [:tommykuo]]

This bug has also resolved when the patches in Bug 1157075 were landed. Because the code in the patches change to use the TaskQueue of reader to dispatch the decoder initialization task! So, the readMetadata in wrong thread problem is resolved.