www.youtube.com - video or audio doesn't play

[webcompat-bot]

URL: https://www.youtube.com

Browser / Version: Firefox 57.0
Operating System: Linux
Tested Another Browser: Yes

Problem type: Video or audio doesn't play
Description: Hovering over video thumbnails do not show a snippet of the video; this works in Chrome
Steps to Reproduce:

1. Navigate to YouTube
2. Hover over a video thumbnail

From webcompat.com with ❤️

[wellington1993]

Hi,

i can reproduce the same at Firefox Nightly 57 on Windows 10.

Thanks.

[MDTsai]

Confirmed, while hover on thumbnail on home page, some video shows snippet like GIF animation, not every video. But I try on same video, works on Chrome, not on Firefox. Spoof UA string to Chrome gets

TypeError: document.registerElement is not a function
[Learn More]
desktop_polymer.js:22:315

Move to needsdiagnosis.

[denschub]

This is pretty much deliberate right now: https://twitter.com/TeamYouTube/status/885939936007864321 not sure if we should diagnose that one... In any case, this is actually pretty simple, since we do not support document.registerElement (actually, we do, but it's pref'ed off), and people should probably use CustomElementRegistry.define() now.

@adamopenweb do you think we should start a thread on the mailing list to track the thumbnail-preview thingy?

[adamopenweb]

@denschub I'm thinking we should give them some time to work on it. Let's keep this issue open and check back on it in a few weeks.

It's good for us to support our partners. In this case we know they are working on the enhancement for FF, so I don't want to come across as pushy. But let me know if you feel differently.

cc: @karlcow

[wisniewskit]

Just for reference, there is some work going on in Firefox to support Custom Elements (the meta bug is here).

[karlcow]

As of today this is still the case.

@denschub @wisniewskit

1. will our implementation of Custom Elements magically solve the issue? If yes let's duplicate to the appropriate bug in bugzilla.
2. Even with our implementation, Google will need to adjust their code? if yes, let's contact Google now so they can prepare their code to be future compatible.

[denschub]

@karlcow so, I do not have answers to your questions at this time. Custom elements are now enabled in Nightly per default (look out for the dom.webcomponents.customelements.enabled pref), but the thumbnails still are not animated, so at least for right, now, the answer is "no".

For 2, I tend to go with a unclear probably. The thing is... if you look at the dependency tree for Custom Elements in Bugzilla, you'll see that there are a lot of open issues left. Our implementation targets to be spec-complient, but Chromes implementations seems to follow the same goal[0], so it may work just fine when we implemented Custom Elements. But as of right now, there is no way of answering your questions with certainty, so I guess we'll have to wait.

However, I wouldn't assume we get to this point soon. Custom Elements are complex, and implementing it seems to be really time consuming.

[0]: I am judging this based on the number of passing WPT in Chrome, assuming the WPTs cover "everything". I did not do any research on this beyond that.

[wisniewskit]

I just hope that their version of Angular supports Custom Elements v1, rather than only v0. Otherwise it won't matter if Firefox implements v1, they will still have to update their site for it to be usable.

[karlcow]

So for now let's make it a duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=889230
And we will revisit when the custom elements are implemented fully.

[karlcow]

Close as duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=889230