The January release of Google Chrome will prevent videos from auto-playing:
Starting in Chrome 64, which is currently earmarked for a January 2018 release, auto-play will only be allowed when the video in question is muted or when a "user has indicated an interest in the media."
The latter applies if the site has been added to the home screen on mobile or if the user has frequently played media on the site on desktop. Google also says auto-play will be allowed if the user has "tapped or clicked somewhere on the site during the browsing session."
"Chrome will be making auto-play more consistent with user expectations and will give users more control over audio," writes Google in a blog post. "These changes will also unify desktop and mobile web behavior, making web media development more predictable across platforms and browsers."
I mean, really. The more advertisers annoy the shit out of us, the less effective it will be effective.