4k Monitor fullscreen video playback in a pip window.

Hello all,

I’m blessed with having a 43” 4k monitor at work, and as well, at home. I have both a MacBook Pro Retina and windows desktop computer hooked up to them. I love working on the monitors but I have one problem with it, watching videos. E.g. YouTube, Lynda.com, Netflix, etc. Within the video player there is a fullscreen button, that when pressed, it will make the video go fullscreen (like it should). But my problem is, I’m trying to multitask while having the video play. I was hoping there’s a way where I can press the fullscreen button and it will give me a resizable borderless window that is movable and able to keep-on-top option. I tried to do some research but came up short. So, I’m turning to you guys. How can one do something like this?

Thanks for reading and responding to my question,
Throdne