A YouTube Experiment Resizes the Player Dynamically

Update (June 2014): It's now a regular feature and you can no longer disable it.

There's a new YouTube experiment that changes the video player's size, depending on the browser window's size. When resizing Chrome's window, YouTube switches from 360p to 480p and to 720p, while the player gets bigger.

Here's the same video in a larger player (480p) and an almost fullscreen player (720p) on a 1080p display:

Here's the regular YouTube interface. The screenshot shows a maximized Chrome window on a 1080p display, just like the previous screenshot:

YouTube's "stats for nerds" show the size of the player ("dimensions") and the video resolution:

The nice thing is that the player resizes automatically and you don't have to click a button. It's the power of responsive design. The YouTube player still has a "large player" button, but it only moves the right sidebar and centers the player.

{ Thanks, Maurice Wahba. }