How can I add a background image to video on Shopify without apps or YouTube?

[Vyk]

Hello guys, I'm working on a project and I want to add video to Shopify without using apps and youtube. I use this code: 

<video controls="controls" style="max-width: 100%; height: auto;">

<source src=" VideoURL" type="video/mp4" />

Your browser does not support our video.

</video>

But the problem with this is that I can't add any background image to it. Maybe someone knows some extra code to add video with background image before customers press the play button?