Ultra-high-definition content has been gaining prominence these past couple of years, with Netflix, YouTube and many other video services bolstering their content to include 4K resolution. Unfortunately, some Firefox users aren’t getting this option, with the browser capping them at 1080p and in rarer occasions 1440p.

While the issue was brought up by KitGuru’s senior editor Leo Waldock, one of the first notes regarding the problem can be traced to 2015 on Mozilla’s own support page. True enough, YouTube’s increasingly popular 4K option could not be found when using Firefox, but appeared for the very same videos when utilising a rival browser.

It seems that not all Firefox users are affected by the issue, with Reddit speculating that the ones that are could be unintentionally blocking the VP9 codec and forcing H264 instead by using add-ons such as h264ify. The issue is even more inconsistent for some Firefox users, who report that only select videos that would usually carry the option are omitting it when using the browser, while others have the option as intended. Fortunately for those that are suffering, there is a fix.

Firstly, users are instructed to open a new tab and place about:config in the address bar. A warning message appears after clicking enter, explaining that changing settings can be harmful but the process is simple enough to click “I accept the risk!” without worry. Next, type media into the search bar (not the address bar) and navigate to media.mediasource.webm.enabled. Double click or right click this option to ensure that it is enabled.

Three out of four of the affected staff here at KitGuru reported that this fix rectified the situation, with the fourth not having experienced the problem despite the option being set to false. Redditors claim a better experience with YouTube as a whole with the option enabled, however, making it worthwhile to check regardless of whether the user is affected or not.

Aside from the fix outlined by Mozilla’s Support Community Manager Rachel McGuigan, the company has yet to comment on the ongoing problem. We’ve reached out to Mozilla and will update this story as more information comes to light.

KitGuru Says: Considering ‘Quantum’ was such a momentous update for Firefox, it’s strange how an issue like this can slip under the radar without a fix in progress. 4K media is only set to rise in popularity, too, meaning that Mozilla has a limited period of time to close the gap if it doesn’t want to fall behind other browsers. Have you experienced issues playing 4K content on Firefox?  

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