YouTube app will soon dynamically adapt to different video sizes
I have some bad news—people will never stop shooting vertical video. This battle is lost, guys. It's time to move on. Google is moving on by making the YouTube app a little less awkward when watching such a video. In the next update, YouTube will dynamically adapt to different video shapes and sizes.
Let's say someone shot a video vertically. Right now, you get black bars on either side unless you switch to full-screen. However, that also hides most of the app's UI and controls. When the new version of YouTube rolls out, the player window will resize to fill as much of the screen as possible with video—square, 16:9, vertical, whatever.