1199904 - No audio in YouTube or A/V sync very broken

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, defect, P1)

Description

[Jean-Yves Avenard [:jya]]

STR:

1: Open https://www.youtube.com/watch?v=XqLTe8h0-jo
2: Seek to 60s
3: Change video resolution to 1080p
4: Wait for playback to restart
5: Seek to 5s

What's happening:
after seeking to 5s the spinner goes on while data is being rebuffered and playback restart.
However, there's now no audio.

After about a minute audio will start playing, but about 1 minute A/V sync off from the video.

What should be happening:
Audio and video starts playing, in perfect sync.

Comment 1

[Jean-Yves Avenard [:jya]]

I can reproduce this behaviour with almost every youtube videos.

Comment 2

[Jean-Yves Avenard [:jya]]

about:media content
https://www.youtube.com/watch?v=o6BXpFBhZZQ
	mediasource:https://www.youtube.com/cc630fc2-20d0-2042-b817-21dc10010d22
	currentTime: 28.929095
		SourceBuffer 0
			start=0 end=131.773151
		SourceBuffer 1
			start=0 end=131.72
	Internal Data:
	Dumping data for demuxer 14e2e0230:
		Dumping Audio Track Buffer(audio/mp4a-latm): - mLastAudioTime: 60.813015
			NumSamples:5675 Size:3419296 NextGetSampleIndex:2619 NextInsertionIndex:5675
			Buffered: ranges=[(0.000000, 131.773151)]
		Dumping Video Track Buffer(video/avc) - mLastVideoTime: 29.400000
			NumSamples:3293 Size:33346082 NextGetSampleIndex:736 NextInsertionIndex:3293
			Buffered: ranges=[(0.000000, 131.720000)]
	
Notice the value for last audio time: 60s while video is 29.4s ; that's after letting video replay for 25s.

Comment 3

[Jean-Yves Avenard [:jya]]

Attachment: P1. Only start decoding ahead after explicitly requesting data.

Decode ahead will be stopped when seeking or when switching resolution.

Comment 4

[Jean-Yves Avenard [:jya]]

remote:   https://hg.mozilla.org/integration/mozilla-inbound/rev/3f5637c65b9a

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/3f5637c65b9a