It looks like I can replicate SMTC changing those control buttons to the Media Control buttons of my keyboard and changing them to global as you said. Even though it doesn't appear anywhere I'm doing it, so I'm controlling it blindly, but it's better than nothing. And in theory there could be conflicts if I have apps that do support SMTC and xmplay opened at the same time (because they will both respond to my inputs), but I will just be cautious with that. Thank you for the help.