We recently updated the video player on desktop to automatically adapt to the shape of the page and provide maximum space for the video. While there's no way to undo the change, share your thoughts via our official feedback tool for us to work on it: https://goo.gl/xAwmTv
Thanks for the feedback! Can you also submit this using our feedback tool? Here are the steps: https://goo.gl/WdI0BK . This will help us improvise, thanks!