Having trouble with fullscreen video on iPhone

I'm working on a html5 video player with custom controls, there's fullscreen button that works fine on PC and Android. But is not working on iPhone since there's no support for the Fullscreen API (developer.mozilla.org/en-US/docs/Web/API/F…). What other alternatives do I have?

The video element comes with default controls if required, and there's a fullscreen functionality that works on iPhone, but I don't know how that is implemented, any ideas?