Safari 10 on macOS Sierra has a useful Picture-in-Picture (PiP) feature to playback HTML5 videos in a small "always-on-top" window, just like on iPads with iOS 9+. To activate, just right-click a playing video and select Enter Picture-in-Picture. However, not all web videos seem to allow this, as they pop up their own menus without the PiP option. Here are two ways to try to enable PiP.
I've tested this on YouTube:
- First, start the video playing.
- Right-click on the video, and the standard YouTube menu appears.
- Just ignore that menu and right-click again, and the standard Safari video menu appears.
- Now, just select Enter Picture-in-Picture.
However, some sites still show their own menus on the second right-click. If so, then try this instead.
- Open SafariPreferences... > Advanced, and check Show Develop menu in menu bar.
- Now, just as previously, start the video playing.
- Try the right-click again, and hopefully, the Safari video menu appears.
Hope someone finds this useful!