[Q] Qt Nexus 5 front/rear facing camera topic

Hello i use the Ubuntu Touch in connection with my Nexus 5.

I want to use the pictures from the front and rear facing camera but where do i find them?

On my Host-PC I use OpenCV with the command

Videocapture cap(X);

from a USB-camera. The device is in /dev/videoX but where do I find the front and rear facing camera in Ubuntu Touch from the Nexus 5?

Thanks