This is according to a report from 9to5Google in which Google has added more criteria in which it determines whether or not a video can autoplay. One of those criterias is that the video must be muted or not feature audio, meaning that a video can be autoplayed in the background as long as there is no sound, so basically no harm no foul.
Hopefully this means that in the future, there will no longer be anymore nasty surprises when it comes to loading websites and getting a shock, especially if you have headphones on. Other criteria include users previously tapping/clicking on the site during the browsing session, added to the Home screen on mobile, or if the user has frequently played media on the site based on the Media Engagement index, like if you were to browse YouTube frequently, for example.
These changes aren’t live yet and are part of Chrome 66 which means that if you’re not part of the beta, then you’ll have to wait until its public release to take advantage of these new features.