How to stop videos from auto-playing? Firefox says the option is already checked, I have added FlashBlock Plus, and they still autoplay?

Open up Firefox
In the address bar, add about:config
This might void your warranty
Select yes


The preference "media.autoplay.default" should show up, and its value should be “0,” which will permit autoplaying videos. Double-click the value and change it to one of the following

1: Block all autoplay videos
2: Get asked on a by-domain basis about whether or not to autoplay videos
I have "Media autoplay default" set to 1...Show more

I use an add-on called Disable HTML5 Autoplay. It seems to work for most things....Show more