You may have noticed that starting from late summer 2015, Google Chrome no longer autostarts videos open in background tabs, until you actually click on that tab.
Videos still can be played in the background, but you have to open a tab for it to start. Some reasonably think that’s an idiotic feature, mostly because no interface setting exists to change that behavior. It doesn’t mean you can’t change that. All you have to do is open Google Chrome flags by navigating to
chrome://flags/#disable-gesture-requirement-for-media-playback
not chrome fags but chrome flags. Here, you have to ENABLE the DISABLE gesture requirement for media playback flag. Yes, that’s a logic nightmare – you have to enable a disable. Restart the browser, and now videos will autoplay when you open them in background tabs.