DSLR Webcam on Raspberry Pi

I want to use live webcam images in a Processing sketch.
I have tried the example code from: https://processing.org/reference/libraries/video/Capture.html
Processing isn’t able to detect my webcam.

I am running Processing 3 on a Raspberry Pi 4 B.
My webcam is a DSLR.
I am using a combination of gPhoto2, video4linux2loopback and ffmpeg to create a video stream from the DSLR.
I am using these libraries to create an mjpeg stream and outputting it to: “/dev/video0”
I have attached a screenshot of the setup of this stream.

I know this stream is working as I am able to see webcam footage using an online webcam testing service:
The “Device Name” I have to select for my webcam is “Dummy video device (0x0000)”.

The problem I have is that “Capture” in Processing 3 won’t detect this webcam.
I have also tried “Movie” and used my stream location “/dev/video0” as the filename.
This did not work either.

Does anyone have any ideas on what I can try to get processing to read in my webcam stream?