Firefox users who visit Google's video hosting site YouTube may have noticed that the site limits the resolutions that videos are made available in.
In particular, any video resolution higher than 720p may not be made available. Other video resolutions that are available may not be provided as well including 144p, 240p or 480p.
It does not really matter if Adobe's Flash Player is being used to watch videos or if YouTube's HTML5 video player is used: resolutions are limited, usually to 360p and 720p, with all other resolutions are missing from the selection menu.
That's problematic for the user but also for Mozilla, as users may use a different browser to play videos on YouTube in different resolutions.
Google's own browser Chrome and Microsoft's Internet Explorer are for instance not limited in regards to video resolutions.
Fixing the issue
What many Firefox users don't know is that it is possible to configure the browser so that all video resolutions are displayed on YouTube when users connect to the site.
Right now, a configuration value needs to be changed for that. In the future, this won't be necessary any longer as Mozilla will enable it by default for all users of the browser.
- Load about:config in the browser's address bar and hit enter.
- Confirm that you are careful when the prompt is displayed.
- Search for media.mediasource.enabled. The preference is set to false by default.
- Double-click the preference name to set it to true and enable it.
- You may need to restart the browser before the change takes effect.
When you visit YouTube afterwards and click on the cog wheel icon in the interface and there on quality, all available video resolutions are displayed to you on the site so that they can be played.
Note: If you have Adobe Flash installed, you may need to switch to YouTube's HTML5 player. To do so, load https://www.youtube.com/html5 and click on the "Request the HMTL5 player" button.
From Firefox 33 on, the button is not displayed anymore so that you cannot switch to Flash manually using the page. The HTML5 video player will be used by default.