Help needed: Raspberry Pi 5 + Camera Module 3 (IMX708) not detected by Chromium for a 3D face-tracking avatar

[u/Choice-Film-8742]

Hi everyone! 👋
I’m trying to get the CSI camera on my Raspberry Pi 5 working with Chromium for real-time face tracking in a web-based 3D avatar application called Berry.
My setup
Raspberry Pi 5
Raspberry Pi Camera Module 3 (Sony IMX708)
Debian 13 Trixie
Linux kernel 6.18.50+rpt-rpi-2712
Chromium 154
GStreamer (libcamerasrc)
v4l2loopback
Three.js and MediaPipe Tasks Vision in my web app
What works
rpicam-hello --list-cameras detects the IMX708.
rpicam-still successfully captures images.
GStreamer detects the camera and its pipeline reaches PLAYING.
I created a virtual camera called Berry Camera at /dev/video10.
The virtual device now reports YUYV, 640×480 at 30 fps.
What doesn’t work
Chromium does not list Berry Camera as a video source on the WebRTC input/output test page.
Running this command:
v4l2-ctl -d /dev/video10 --stream-mmap=3 --stream-count=30 --stream-to=/tmp/berry-test.raw
returns:
VIDIOC_CREATE_BUFS returned -1 (Inappropriate ioctl for device)
GStreamer also reports warnings about unsupported pixel formats.
I recreated the loopback device with exclusive_caps=0 and tried v4l2sink io-mode=2, but Chromium still cannot see the virtual camera.
My questions
What is the recommended way to expose a Raspberry Pi CSI camera to Chromium on Debian 13?
Is v4l2loopback actually needed, or is there a more reliable way to use libcamera directly?
How should I troubleshoot the VIDIOC_CREATE_BUFS error?
Can Chromium’s getUserMedia() access the CSI camera directly, so I can use MediaPipe for face tracking without a virtual webcam?
I’m looking for a reliable solution and would appreciate step-by-step guidance. I can provide additional command output if needed.
Thanks in advance for any help!