Brian has a series of VIVOTEK IP cameras. But he can't cast to Safari, Chrome or Firefox. EDGE and Explorer work though. Leo says that he may need to install an extension, and it may not be available. VIVOTEK may not have written plugins for it, or it may use a technology which other browsers don't support. Browsers have depreciated some of those plugin technologies lately. And chances are, they aren't secure.
From the chatroom, there is a way and here's a video on it - https://www.youtube.com/watch?v=JEPuhmPIzm4