Control inline video—and more—in Safari
This is another oldie but goodie from Mac OS X Hints, explaining how to enable the Debug menu in Safari. To do that, quit Safari, open Terminal, paste the following line, and press Return:
defaults write com.apple.Safari IncludeInternalDebugMenu 1
When you relaunch Safari, you'll have a (really long) Debug menu on the far right of Safari's menus. And just why might you want a Debug menu in Safari? Kirk McElhearn offers up one good reason:
Auto-play videos suck. They use bandwidth, and their annoying sounds get in the way when you’re listening to music and open a web page. …
But you can stop auto-play videos from playing on a Mac. If you use Chrome or Firefox, it’s pretty simple, and the plugins below work both on macOS and Windows; if you use Safari, it’s a bit more complex, but it’s not that hard.
In Safari, they key is the Debug menu, as Kirk points out. Go to Media Flags and select (activate) Disallow Inline Video, and that should be the end of auto-playing video. See Kirk's blog post for ways to do the same in Firefox and Chrome.
Beyond auto-play video, though, there's lots to geek out about in the Debug menu…