How to play 4k/1080p video based on device support

I have 4k and 1080p video (and 720, 480, etc), but I want to play the video that is supported by our users device. What is the right way to configure the Player for either 4k or 1080p based on device capabilites. (I may also want to allow my users to explicitly put a cap on the format they play (as streaming a 4k video could be really challenging for some user's ISP bandwidth)