It looks like the video is in its own section, grid or grid row and that is set to be the same height between ALL break points. You can either set it the height to auto or match the video fundamental height until you hit other breakpoints, which at that time, I would have it go bigger than keeping it at the same percentage with all the way through the screen sizes and device.
Utilize Min Heights and Min Widths from the get go and you will find it easier to manage.