What is USB OTG? Here’s how to use USB drives and more on your smartphone
Note that you would need a video capture card that will connect to your phone over USB OTG as the output and to an HDMI cable ...
Hackaday9y
First Raspberry Pi Zero Hack – Piggy-Back WiFi.
He couldn’t bear to disturb the small dimensions of the Pi Zero by using the USB On-the-Go (OTG). The OTG is needed to convert the micro-USB connector on the board to a full USB-A connector.