YouTube videos black, only audio in Firefox

Question

When I play a YouTube video on my computer, it seems to play fine, but the whole video is black. This happens only when I play the video in Firefox.

I'm using Windows 8.1

What I did so far:

• Restarting Firefox
• Reloading the page with Ctrl+F5
• Seeking back and forth in a video
• Playing different videos, with and without playlist
• Cleaning the cache, cookies, history and everything else...
• Updating Firefox to the latest version
• Disabling all extensions
• Deactivating all plugins
• Opening the video in a private window

Still the same...

I don't want to restart my PC or uninstall and reinstall Firefox, there must be a way around that.

And before I forget:

• The video ads are black too.
• HTML5 videos on other websites work fine.
• I can see all the thumbnails of the video when moving the mouse over the seek bar.
• The videos are not opening in Flash player through the browser - they are the HTML5 versions

Solution 1

The Mozilla support forum has an entry for this problem and it relates to the browser using hardware acceleration causing the problem.

Source: https://support.mozilla.org/en-US/questions/1044374

1. Click the Firefox menu button
2. Click Options
3. Click Advanced
4. Under General untick Use hardware acceleration when available

If you disable hardware acceleration it will fix the problem but it may cause problems elsewhere with, for example, WebGL and other browser graphics technologies.

Solution 2

This question describes disabling all extensions and plugins and still having the problem. In that case, Big Chris's answer is a pretty good bet for the solution. For people who have not tried disabling extensions, and that answer doesn't fix the problem, there is a good chance that extensions are an additional issue.

In my own case, many videos (at many web sites), display just a black window (not even audio). Some are HTML5, some are Flash, and hardware acceleration is off. The issue turned out to be that many sites won't work if ads and/or trackers are blocked. For example, I use Adblock Plus to block pop-up ads and Ghostery to block trackers.

So far, all problem sites for which Big Chris's solution didn't work, were fixed by whitelisting the site or pausing blocking on one or both of those extensions.

Comments

[Julian]

Pleas let us know what OS you are using.

[td512]

Have you tried resetting Firefox to factory defaults?

[Kinnectus]

I believe this may be related to hardware acceleration with the Flash player: Try disabling hardware acceleration from the Flash settings: support.mozilla.org/en-US/questions/1009940

[Forivin]

@Nifle I'm using Windows 8.1. Sorry, forgot to mention that.

[MrWhite]

@BigChris, Won't HTML5 video take priority over Flash these days - I thought Flash is only used as a fallback? FWIW, YouTube works OK for me in Firefox and I don't have Flash installed.

[Forivin]

@TD.512 Have you tried resetting Firefox to factory defaults? I don't wanna lose my settings, session, bookmarks, etc.

[Forivin]

@BigChris The Flash plugin isn't even activated, I highly doubt this is Flash related. YouTube uses HTML5.

[td512]

before resetting firefox: goto about:accounts and sign up for sync and wait for about half an hour so the cloud can fully sync. then reset

[Kinnectus]

Right click the video window and see if you get the Flash options or the HTML5 - just to rule out Flash :)

[Julian]

I assume you have tried starting firefox in safe mode?

[Kinnectus]

Also: support.mozilla.org/en-US/questions/1044374 - it does say about Firefox not liking HTML5 videos and that it may be hardware acceleration related...

[Forivin]

@TD.512 I don't want my session, bookmarks, history etc anywhere else than on my hard disk. :/

[Forivin]

@BigChris already did the context menu thing, and it is html5, I'll check your link now

[Forivin]

@BigChris Unticking Use hardware acceleration when available in Menu ≡ > Options > Advanced > General fixed the problem for now. But this will probably have a negative effect on other things like WebGL I guess. :( Is there maybe another solution?

[Kinnectus]

Yup... wait for Mozilla/community to fix it, update your drivers, use a different browser ;)

[IMB]

Was scratching my head for awhile until I noticed I had an Addon called Block Site activated after a random browser crash and I may have added Youtube sometime ago. Disabling it fixed the issue.