The responsive view in AllVideos takes into account that videos will be wrapped in a 16:9 canvas. Yours has a much higher ratio. As such, there is padding below the video. To fix it, either create an MVC override (see how here: www.joomlaworks.net/support/docs/allvideos) or add this in your template's CSS file:

You're welcome.

If you like AllVideos, I'd appreciate it if you could post a review and/or rating for the plugin at the Joomla Extensions Directory here: extensions.joomla.org/extension/allvideos/