video on index page

I am using a video in an Index page stack so it autoplays upon landing on my site. I am using the Moksha template.

Is there any way to change the aspect ratio of it to better present on mobile? Too much is getting cropped out.

I have checked all the mobile setting in the Design Center, but there are no controls there or in the menu box where you upload the url share code.

Is there in fact a place to change a setting for mobile? OR is there a way to overwrite code? thanks jbds