Video background not responsive

Hi,

I have set a video as a background on my homepage, http://www.swoop.aero. The video won’t play on a mobile so I’ve set a place holder image.

However, when I’m on my desktop and I scale my window, the video does not the screen, and the placeholder image shows up behind it. This also happens if I go to desktop view on a mobile device.

Your demo http://demo.agnidesigns.com/fortune/demo16/ is set up the same but when I scale the window it has a black background behind it. On mobile it has a static image.

If I can’t get the video to fill the screen, how can I stop the placeholder image showing behind it? Do I need to set a solid colour behind it and if so, how do I do that?

Thanks, Zoe