1330713 - Youtube videos won't play when there is a pending update for Firefox beta

Status: NEW

(Firefox :: General, defect)

Description

[Stuart Philp :sphilp]

I'm not 100% on this, but I'll report it as I've seen it. 

Mac OSX 10.12.2, Firefox Beta 51.0b12 (since updated to b13). Untested on Windows and others.

I use beta as my regular browser, occasionally I'll go to watch a youtube video and it just sits at a black screen. The player is there, I can see the download progress bar, and I can scrub through to see different still images from the video, but the video itself won't play. 

This happens fairly regularly, most of the time videos work well, but occasionally it will do this. I've thought that since it happens on a fairly regular cadence (weekly?), there might some underlying reason for it, and it seems that checking for an update and restarting will resolve the issue. It may also just be the hard restart too. I'll test a force-quit next time I see the issue.

Steps to reproduce seems to be just load a youtube video (any video seems to cause it) while an update is pending on beta. Will try to get more concrete steps, as well as checking for console errors and such.

Workaround:
When a youtube video isn't playing as expected, check for updates in the "Firefox" -> "About Firefox" menu item. If an update is available click the "Restart Firefox to Update" button. Upon restart youtube videos should play again.

Comment 1

[:Gijs (out for now; he/him)]

I've seen this as well (also on beta). Anthony, is there some way we can gather data about this if we see it again, and/or do you have a clue what might be going on?

Comment 2

[Stuart Philp :sphilp]

Happened again this morning. I checked the console and didn't see anything odd. This time I also just quit Firefox (cmd-q on mac) and restarted rather than going through the update process. On restart videos were fine again. I did then check if there was an update sitting and there was (51.0bb14), but it didn't need to be applied to fix the problem.

Only other notable thing I can think of is I left the browser open over night, putting my mbp in sleep by closing the lid. Otherwise nothing changed between last night when this was fine and this morning when it wasn't.

Comment 3

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

Jean-Yves - can you take a look at this one?

Comment 4

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

Julien - do you know of anything the updater could be doing that could cause this?

Comment 5

[Julien Wajsberg [:julienw]]

I don't think I'm the right Julien, sorry :)

Comment 6

[Julien Wajsberg [:julienw]]

Maybe Robert Strong ?

Comment 7

[Jean-Yves Avenard [:jya]]

I see plenty of issues occurring when an update has been applied and the browser hasn't been restarted.

Like with reviewboard, some menus no long appear.

I don't think this a problem with media playback per say.

Comment 8

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

Kaku talked with me offline about this bug. Agree with kaku and jya on comment 7. This problem should not be in media playback. IMO, this should not be important bug as P1 since users usually will do "Restart Firefox to Update". So I am going to reset the priority and change its component to "General" back to see if someone knows what it is going on during the update.

Comment 9

[Robert Strong (they/them - no direct email)]

A pending update consists of performing a download, making a copy of the installation, and applying the update to the copy. If videos aren't playing because of any of these steps there must be something very weird going on. If another instance updated I could see this happening due to an update.

Comment 10

[Blake Winton (:bwinton) (:☕️)]

I'm seeing this reasonably consistently on Developer Edition for the last few versions…
Given that (I suspect) people are watching a lot more videos these days, perhaps we could get some attention on this bug?

Comment 11

[:Gijs (out for now; he/him)]

(In reply to Jean-Yves Avenard [:jya] from comment #7)

I see plenty of issues occurring when an update has been applied and the
browser hasn't been restarted.

Odd, I haven't seen any other than video playback issues before now. The only other thing I'm aware of is that new content processes fail to launch if another process has applied the update "under" the running instance, as noted in comment #9 - but this doesn't normally happen unless one uses the browser toolbox or is on linux and the distro updates things from under us. In that case, I agree we have bigger issues. But I don't think that's the case here.

So I'd like to repeat my question from comment #1: what can we do to diagnose what is wrong when we see video playback failing? TBH, I'm not even sure it's actually related to updates at all, rather than just the fact that the browser has been up for a long time. But I have no idea how to debug it. I imagine it could also be related to e.g. an EME plugin update, but again, no idea how to debug it or narrow it down to something like that. How would we test such an hypothesis / gather data when playback fails?

Comment 12

[Jean-Yves Avenard [:jya]]

It will depend on what they are playing.

I am aware of some issues with the Widevine CDM ; where there's pending update and a new process GMP process is launched ; the signature no longer matches and the CDM refuses to load video.

Also, IIRC there was an issue if a new content process is launched, that will be the one from the updated version), the preferences could have changed in between and you have an incompatibility between the pref in the old parent process and the new content process.

Difference of prefs could mean it's incorrectly reading a value and that would no allow some videos to play.
For that scenario however, I'm just guessing.