Hi there
I wonder if this is possible... With the Canon app we can view the camera's output as we all know.
Is it possible to use the USB as video out?
It works with dslr controller. A little laggy but works, even wit raw. Prepare for error codes though.
Maybe not what you, re after?
Yes, one can access the liveview using the ptp protocol. Libraries for ptp exist for many uses and platforms, even Arduino.
You might also look into gphoto.