Closed Bug 1107611 Opened 6 years ago Closed 6 years ago

MSE WebM playback on youtube stops intermittently after 9-15 seconds


(Core :: Audio/Video, defect, P5)

33 Branch





(Reporter: cajbir, Unassigned)


(Blocks 1 open bug, )


Steps to reproduce:

1) Go to
2) Play video

What should happen:

3) Video plays through

What happens:

3) Video stalls at 9 seconds or so

Looking at the internal state of the Media Source shows the following:
	currentTime: 9.249999
		SourceBuffer 0
			start=0 end=10.022
		SourceBuffer 1
			start=0 end=9.999
			start=10 end=119.999
	Internal Data:
	Dumping data for reader 7f31d0091000:
		Dumping Audio Track Decoders: - mLastAudioTime: 10.021219
			Reader 0: 7f31cdc66000 ranges=[(0.000000, 10.022000)] active=true
		Dumping Video Track Decoders - mLastVideoTime: 9.292000
			Reader 2: 7f31d07b8800 ranges=[(20.000000, 119.999000)] active=false
			Reader 1: 7f31d27ca800 ranges=[(10.000000, 79.999000)] active=false
			Reader 0: 7f31cdc63000 ranges=[(0.000000, 9.999000)] active=true
From here it looks the Audio playback has stalled as it has no data beyond 10.022 seconds. Last audio time is 10.021219 seconds. 

Attaching with the debugger and dumping the list of threads shows no media decode threads. Maybe it has stopped for some reasons?
An initial git bisect shows this is introduced in:

commit ff0f55d7cb947545cac00b509043a0dda5f0241d
Author: Joe Olivas <>
Date:   Tue Nov 11 16:30:52 2014 +1300

    Bug 922314 - Add support for decoding VPx via MediaFoundation on Windows.  r=cpearce,kinetik
    Refactor WebMReader's VPx decoding out to SoftwareWebMVideoDecoder and introduce a new IntelWebMVideoDecoder that uses the MediaFoundation/MFT backend to decode VPx when the requisite hardware and software is available.

:040000 040000 15de9773ddacb9965542d54e8b5c494193c6f373 c9ca43043b6ca325bcbd6a2cbce584ca14a272fd M	dom
:040000 040000 a73eabf661571764bc603c743556a7f207de3119 34255b0cce497c73a8b1a7fda12faf358e124b4a M	modules

Doing some more investigating to confirm.
Is this still an issue?
Flags: needinfo?(cajbir.bugzilla)
Priority: -- → P5
Can no longer reproduce.
Closed: 6 years ago
Flags: needinfo?(cajbir.bugzilla)
Resolution: --- → WORKSFORME
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