I think I speak for a lot of us when I say that I’ve had a good scare from a video that started playing automatically when I opened a website. Scrambling to find which tab the sound was coming from was also not a very graceful dance either.
Chrome does have a system that only plays videos from websites where autoplay is not an issue, such as Netflix or YouTube, while blocking the sounds from the websites that have those small videos in the corner of their page. From experience though, Chrome doesn’t always catch them in time, if at all.
Firefox decided to follow suit on the issue and has a more straightforward approach to the problem: it simply blocks by default any website that attempts to play video with audio. The only websites Firefox will not tamper with will be the ones that the user has previously granted camera and microphone access to.
An icon will appear in the URL bar that will let you know an auto-playing media was blocked.
Of course, Firefox users can easily work their way around the block with each website. If autoplay is your thing, you can re-enable it in seconds, with just one click.