However, there are some websites like YouTube and Plex that do not use standard HTML5 video wrappers which break the Mac’s PiP function. Enter a neat open source app called PiPifier.
PiPifier works by intercepting code in supported websites and enabling the PiP function. PiPifier is also recompiled as a Mac AppStore app so you don’t need to compile it from its source via Xcode (and comes with the stamp from Apple this is a safe app).
To use PiPifier, load up a video then you need to make sure you interact with the video player once before pressing the PiPifier button (like pressing play/pause).
Download Now (Free)