Since adding the ability to show embedded videos we’ve recognized that the default size is very small, rather than make it larger by default we’ve also had a link which would quickly take you to a new window where you could view the video in larger format.
If you’ve wished that the embedded videos were larger, wish no more. You can now make them as large or small as you like.
After opening the Videos section while viewing a dance
Just grab either the right edge, bottom edge or bottom-right corner and drag until the video is the size you want