Usb Webcam blocked by Mega 2560 on RPi 4

Hi all,
This is my first post so please excuse if I don’t format correctly.
I am using a Raspberry Pi 4 model B for a project with openFrameworks and Arduino.
I have everything set up and working correctly but I now want to use computer vision with a PS3 eye camera so when movement is detected an LED is switched on.
Currently I have openframeworks talking to arduino via serial with no issues and can switch the LED on/off with mousePressed().
However, when I try to call the vidGrabber.draw() the mega2560 is blocking the video.
Using terminal I can see that both the megaboard and the USB camera are set to device ID 0 which seems to be causing the issue. Can anyone suggest how to assign usb cam and the mega board different device IDs?