This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Autoplay not always blocked

  • 3 replies
  • 2 have this problem
  • 1 view
  • Last reply by ascaris

Jens Lyn IV
Jens Lyn IV
more options

Firefox 78 sometimes fails to block autoplay, e.g. scrolling the front page of reddit.com or a subreddit will intermittently show videos playing.

This worked in 77. Some about:config entries I'd swear were set in 77 have vanished; I tried adding them manually, but the autoplay blocking is still hit and miss.

Also, not sure if Troubleshooting Information uploaded successfully or the page broke (see screenshot).

Firefox 78 sometimes fails to block autoplay, e.g. scrolling the front page of reddit.com or a subreddit will intermittently show videos playing. This worked in 77. Some about:config entries I'd swear were set in 77 have vanished; I tried adding them manually, but the autoplay blocking is still hit and miss. Also, not sure if Troubleshooting Information uploaded successfully or the page broke (see screenshot).
Attached screenshots

Chosen solution

Setting media.autoplay.blocking_policy to 2 seems to work, but I shouldn't have to do this manually just because Firefox updated.

I'd still like to know if the Troubleshooting Information field in the submission form actually did what it was supposed to.

Read this answer in context 👍 1

All Replies (3)

Jens Lyn IV
Jens Lyn IV Question owner
more options

Chosen Solution

Setting media.autoplay.blocking_policy to 2 seems to work, but I shouldn't have to do this manually just because Firefox updated.

I'd still like to know if the Troubleshooting Information field in the submission form actually did what it was supposed to.

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

There was no troubleshooting information send as that would appear if you click "More system details" in the side menu next to your question, so something went wrong.

See also:

ascaris
ascaris
more options

Edit: I had previously said autoplay blocking from the Preferences | Permissions for autoplay worked on one of my three PCs. Now it's not working on any of them, so my guess is that it's an intermittent issue as the OP wrote, and I just thought it was tied to the machines.

I use FF 83 on Linux, and as of this moment, it ignores the UI under Permissions that is set to Block audio and video (pref media.autoplay.default set to 5) on all of my machines.

I tried starting in safe mode and going to a video site, and this time, it blocked as it was supposed to. After I restarted Firefox, though, and disabled all the addons manually, one by one, it did not block autoplay. It would appear to be a pref that gets temporarily reset in safe mode.

After searching the web about the issue, I found this page, and I set the media.autoplay.blocking_policy pref to 2 as suggested, and indeed, it worked.

Modified by ascaris