Zoom in a YouTube video header to fill smartphone screen

Hello, I want to be able to crop (zoom in) a landscape YouTube video used as a header in order to fill the entire screen (of a smartphone or any other device) instead of the actual behaviour : for now, on mobile, the YouTube video is shown small in order to be displayed on the smartphone screen with two big black strips above and below the video. I don't find any possible CSS Code for this... Is It possible to zoom so the top and the bottom of the Youtube video touch the borders of the screen ? Thank you !