Disabling autoplay videos and media in Chrome is simple. First of all you need to type "chrome://chrome/settings/content" into the URL bar. Then all you need to do is scroll down to the plug-in section, and select 'Let me choose when to run plugin content'.
Type chrome://flags/#enable-tab-audio-muting in the browser's address bar. This should open the experimental flags page of the browser and jump straight to the right flag.
Switch the flag to "enabled" with a click on the link.
Restart Chrome afterwards.