Oana Botisan, Desktop QA Reporter
	Description • 6 years ago

[Affected versions]:
- 58.0 -build 6

[Affected platforms]:
- Windows 10 x64
- Ubuntu 16.04 x64
- macOS 10.13

[Preconditions]:
- Autoplay is on 

[Steps to reproduce]:
1. Open https://www.youtube.com/ in two tabs.
2. Play a video in one of the tabs.
3. In the other tab sign in into a valid youtube account.
4. Let the video play until the end.
5. Wait for the next video to begin and watch behaviour.

[Expected result]:
- The video starts to play without any problems.

[Actual result]:
- The video plays for about two seconds then it freezes. It can be played only if the page is refreshed. 

[Regression range]:
- I will try to find a regression as soon as possible, if there is one.

[Additional notes]:
- For clarifications please look at the attached .gif.

	Oana Botisan, Desktop QA Reporter
	Comment 1 • 6 years ago

You can find the .gif at this link: https://imgur.com/a/mLsNE

Regression range:

- last good build: 2017-10-04 (20171004220309)
- first bad build: 2017-10-05 (20171005220204)
- pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=c3b7759671deae73e40ebca01d7f23a326a4b8c2&tochange=19b32a138d08f73961df878a29de6f0aad441683

Mozregression suggested that this bug might be the one that caused the problem. 

Bug 1324883 - part2: Once a MediaElement receive document unload event, remove all MediaElements in gElementTable with the same uri. r=jwwang

	Mike Taylor [:miketaylr]
	Comment 2 • 6 years ago

Chris, is there someone you can recommend to look at this? Thanks.

	Mike Taylor [:miketaylr]
	Comment 3 • 6 years ago

This doesn't reproduce for me on Mac in 59b05.

Oana, could you see if it still does for you?

	Oana Botisan, Desktop QA Reporter
	Comment 4 • 6 years ago

I check it on beta 59.0b5 and latest Nightly using Mac OS 10.11, Ubuntu 16.04 x32 and Windows 10 x64. The bug is still reproducing on every platform. 
I am using a gmail account to sign in. That might be the cause of the issue, maybe. Because yesterday I managed to reproduce the bug on DevEd 59.0b5 when I sign into my email account (gmail).

	Mike Taylor [:miketaylr]
	Comment 5 • 6 years ago

I'll try again using gmail (instead of @mozilla).

	Mike Taylor [:miketaylr]
	Comment 6 • 6 years ago

Ahh, yes. Just reproduced in 60 using my personal gmail account. No obvious network or console errors.

	Oana Botisan, Desktop QA Reporter
	Comment 7 • 6 years ago

I tested with a yahoo account and the bug is reproducing. So I don't think that the issue is just gmail related.

	Chris Pearce [:cpearce (Not reading bugmail)] Assignee
	Comment 8 • 6 years ago

This is indeed a regression from bug 1324883. The code to try to shutdown decoders when a new load starts is triggered by the YouTube, and it's causing the MSE decoder to be destroyed, blocking playback.

We can back out bug 1376321 to fix this; it doesn't seem that critical.

	Pulsebot
	Comment 9 • 6 years ago

Pushed by cpearce@mozilla.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/c900339ffe3d
Backed out changeset 3e22200b7e83. r=backout
https://hg.mozilla.org/integration/mozilla-inbound/rev/aab04cb5b815
Backed out changeset 9d197f1860e6. r=backout

	Chris Pearce [:cpearce (Not reading bugmail)] Assignee
	Comment 10 • 6 years ago

To be more explicit, the intent of bug 1376321 was to clear the MediaCache when a tab was closed or CTRL+F5 was pressed. However this has the adverse effect of shutting down the video element when a new MediaSource (which doesn't use the MediaCache) is attached to a previously playing media element under some conditions, in particular on YouTube when a user signs in on another YouTube tab.

We should uplift the backout.

	Dorel Luca [:dluca]
	Comment 11 • 6 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/c900339ffe3d

	Julien Cristau [:jcristau] (back April 22)
	Comment 12 • 6 years ago

let's get this on the tracking list for 59.

	Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)
	Comment 13 • 6 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/aab04cb5b815

	Chris Pearce [:cpearce (Not reading bugmail)] Assignee
	Comment 14 • 6 years ago

(In reply to Chris Pearce (:cpearce) from comment #10)
> To be more explicit, the intent of bug 1376321 was to clear the MediaCache
> when a tab was closed or CTRL+F5 was pressed. [...]

I meant to say bug 1324883 here, and elsewhere in this bug where I mentioned 1376321...

	Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)
	Comment 15 • 6 years ago
uplift

Backed out from beta https://hg.mozilla.org/releases/mozilla-beta/rev/e61fa00f6ebf

	David Olah
	Comment 16 • 6 years ago

Verified on Nightly 60.0a1 (2018-03-09), Build ID: 20180309003239 on:
- Windows 10 x64
- Ubuntu 16.04 x64
- macOS 10.13
Bug is fixed.

Reproduced on the same OSes on Firefox 58.0

	Oana Botisan, Desktop QA Reporter
	Comment 17 • 6 years ago

I verified the fix on Firefox 59.0 using Windows 10 x64, macOS 10.13 and Ubuntu 16.04. The issue is not reproducing anymore.