I am working on a Roku TV app (TCL Roku TV) to add text on top of live video. It accepts text input from ECP and displays it on screen. I have this working using roTuner with any of my local TV channels, however I really would like to be able to use it with the CVBS or HDMI inputs. How do I setup HDMI or A/V inputs on a video node. Specifically, what is the streamFormat and what needs to go into content.streams.