Its been available in Android since 2017’s Oreo, but now, picture-in-picture mode is coming to Windows, Mac, and Linux with Chrome 70. Android Police reports that it’s now enabled by default. The functionality will need to be enabled on a per-website basis by web developers, after which you’ll be able to overlay an online video onto your desktop where it can be kept in sight, regardless of which website or program you’re using.
If you want to see how the functionality works, you can head over to YouTube, where you can right-click any video twice and click “Picture in Picture” from the context menu. Once you enable picture-in-picture mode, the tab that the video is playing from will display a small icon, similar to how Chrome will show a speaker symbol to let you locate the source of any audio that’s playing. The video overlay can be moved anywhere on the screen with a quick drag and drop.
Although the functionality is now enabled, it’s up to developers to add it to their websites. YouTube already supports it (albeit via a clunky method that will almost certainly change), but otherwise, you’re going to have to use a Chrome Extension to enable it for other websites.