extending the Vcam app - camera pass through

Hello,
The current version of the Vcam app records what’s inside the UE editor.
If I wanted to extend the capabilities of the app to enable it to show video pass through how would I go about it ?
Would I have to first learn how to enable camera recording on the android / iphone via UE C++ and then see how to inject that code into the vcam app ?

Thanks for any insights.

b