Firefox 51: blocks automatic audio playback in non-active tabs

Firefox will block the automatic audio playback of content in non-active tabs starting with version 51 of the web browser.

There are two types of background audio in browsers: first audio playback initiated by the user, for instance by starting playback on a site and then switching to another tab. Second, audio playback that starts to play in the background without user interaction.

Maybe you have encountered situations in the past where multiple YouTube videos started to play at the same time, or where a site spawned an audio or video ad that started to play automatically even though you were listening to music or watching a video.

The change that Mozilla implemented in Firefox 51 prevents some of these situations. Basically, what it does is block any audio playback until the tab is activated by the user.

So, if you launch a site in the background it won't be able to play audio until you switch to it first.

Tabs that have been activated once continue to play the audio without further interaction. This means that the feature won't impact audio or video playlists.

The audio blocking feature has no impact on sites that you load actively -- read not in the background. This is different from what Google tests in Chrome currently. The company launched a new experimental flag in Chrome that prevents more than one audio source from playing in the browser at any given time.

Mozilla plans to improve the new feature in Firefox 52 further. The organization plans to display a "play" icon in the tab bar of the browser that is linked to background tabs that attempted to play audio.

The play icon, you guessed it, provides you with options to start the playback of the audio directly. This means that you don't have to switch to the tab, locate the player, and click on the play button there to do so.

Firefox users who don't want the new functionality can restore the old.

This is done in the following way:

1. Type about:config in the Firefox address bar and hit the Enter-key afterwards.
2. Confirm that you will be careful if the warning prompt appears.
3. Search for media.block-autoplay-until-in-foreground.
4. Double-click the preference.

A value of false turns the feature off, a value of true is the default value and means that it is enabled.

Mozilla plans to release Firefox 51 on January 24, 2017.

Closing Words

The new feature improves Firefox's handling of annoyances quite a bit. While it is not a catch-all solution, as it won't work for the active tab or tabs activated previously, it does take care of a subset of audio playback annoyances.