(2015-12-22, 18:40)fearo Wrote: My question really is, how do I PHYSICALLY connect the Rpi server to my Nvidia shield, which will serve as the frontend? Through USB?
No, not USB. USB is for peripheral like computer to a USB TV-tuner adapter. USB is not for computer to computer connections, which is essentially what both Raspberry Pi or Nvidia Shield TV is; computers. And no, not HDMI. HDMI is to connect a computer (like a Raspberry Pi or Nvidia Shield TV) to a display or television.
To connect a a computer to a computer at home (or at an office) you setup a computer network, or more specifically a LAN (local area network) and in mordern times a a LAN means via Wired Ethernet or WiFi connected via a network switch (or a network router or access point with a built-in network switch), and that the communication protocol used over LAN today for most purposes is TCP/IP. Not going to do into more details than that what a computer network is and how you setup one at home, for that I direct you to wikipedia and google
https://en.wikipedia.org/wiki/Local_area_network
https://www.youtube.com/watch?v=X221CtO5NQA
Again, you should really re-read the wiki because if had done done so and also fully understod the concept then you would have already known that if they are not running on the same device thn the connection between the backend (server) and frontend (client) is over a network = LAN = TCP/IP over Wired Ethernet or WiFi.
While the Raspberry Pi 2 can run MythTV as a backend fine and the original Raspberry Pi does not quite have sufficient CPU power to run MythTV as a backend, but most people including me will tell you that Tvheadend or VDR is the recommended and prefered backend to run on any Raspberry Pi.
Sorry if this maybe sounds a little condesending but that is what you get when you did not do enough research on your own first and ask if should connect a Raspberry Pi to a Nvidia Shield TV via USB or HDMI. Leason to learn is to always spend some time to read then re-read the wiki and if you still don't understand use google to at least try to search a little before asking questions on forums tht make it clear that you did put enough effort into researching the topic before asking. Spoonfeeding adults is not fun.