YouTube regularly allows you to test the features that the developers have planned for the future – they can be tried by anyone with a YouTube Premium subscription. A recent such experimental innovation is the video scaling option.
The feature is only available on mobile devices – to zoom in and out, use a two-finger pinch-in or pinch-out gesture. According to The Verge, you can zoom in this way up to 8 times. It is not yet clear whether this innovation will appear in the web version of YouTube for computers, since in this case the main difficulty will probably be the implementation of the appropriate interface adapted to the mouse.
Any owner of a YouTube Premium subscription can become a participant in testing this feature – just go to a special page and activate the option, after a while it will work and will be available until September 1.
Source: Trash Box