What to do with template that allows only embedded videos?

I just installed new to theme to my website. Its great video portfolio theme, but it allows adding embedded videos ONLY. I want to add selfhosted videos, which doesnt work (you can add YouTube/Vimeo videos only). I’m not a programmer, so I’m looking for some advice. I was wondering if its possible for me to solve this. Maybe i just open some file and change some code?
Thanks for any help!