YouTube has just announced that the videos with an unusual aspect ratio watched on the desktop - hence on a desktop browser - will no longer appear with black bars. Instead, they will be optimized and stretched to appear bigger.

It does so by removing the default 16:9 frame and optimizing the UI to adjust to different screen sizes. Could this change finally make vertical videos less annoying? (Short answer: No.) Anyway, you can see the difference in the screenshots below.



Before the update and after the update

The change should be gradually rolling out to everyone after being released for the Android and iOS mobile app for some time now.

Source