The YouTube miniplayer and its limit
On youtube.com, the miniplayer button (or the I key) shrinks the video to the bottom corner of the page, so you can scroll comments or pick the next video. It is useful while you stay on YouTube. But it is part of the page: switch to another tab or app and the video is out of sight.
Way 1: picture-in-picture, a mini player on the desktop
Right-click the video twice and choose Picture in picture. Chrome moves the video to a small floating window that stays on top of everything, even when Chrome is minimised. Step-by-step guide.
Way 2: a pop-out button in the YouTube player
Youtube Pop Out Player puts a pop-out button on the right of the YouTube player's control bar and adds a keyboard shortcut. One click and the video floats on your desktop in the picture-in-picture window; click again to bring it back. Drag the window anywhere, including a second screen, and resize it up to the browser's limit. How to pop out a YouTube video.
Way 3: YouTube as an installed web app
In Chrome, open youtube.com, then menu ⋮ → Cast, save and share → Install page as app. YouTube opens in its own window without tabs. You can make that window small, but it is an ordinary window and goes behind other apps when you click them — combine it with PowerToys Always On Top on Windows.
Comparison
| YouTube miniplayer | Picture-in-picture | Pop Out Player | Web app window | |
|---|---|---|---|---|
| Visible outside the tab | No | Yes | Yes | Yes |
| Stays on top | No | Yes | Yes | No |
| Any size | No | Up to a limit | Up to a limit | Yes |
| How to start | Button or I key | Right-click twice | Button in the player or shortcut | Open the app |
| Install needed | No | No | Extension | No |