Using a Photo Camera as Webcam in Linux

Install dependencies:

sudo pacman -Syu ghoto2 v4l2loopback-dkms

gPhoto2: A digital camera download and access program.

v4l2loopback: A kernel module to create V4L2 loopback devices.

Connect the camera to the computer. Verify that the camera is detected with:

gphoto2 --auto-detect

To view the details of the camera:

gphoto2 --summary

To capture a test image with the camera:

gphoto2 --capture-image-and-download

To view the available live view sizes:

gphoto2 --get-config liveviewsize

💡 Tip

If any of the commands above output the error message “Could not claim the USB device”, try:

gio mount -s gphoto2

Load the v4l2loopback kernel module:

sudo modprobe v4l2loopback video_nr=9 card_label="Photo camera" exclusive_caps=1

video_nr=9: Create a loopback video device at /dev/video9. Adjust when needed.

card_label="Photo camera": Set the name of the video device to Photo camera. Adjust when needed.

exclusive_caps=1: Enable exclusive_caps mode that only reports CAPTURE/OUTPUT capabilities exclusively. Necessary for some Chromium/WebRTC based applications.

💡 Tip

To unload the kernel module, use:

sudo modprobe -r v4l2loopback

Verify that the loopback video device is created successfully:

v4l2-ctl --list-devices

Capture the video stream from the camera, and pass it to the loopback video device. Adjust liveviewsize and /dev/video9 to match the actual desired values:

gphoto2 --stdout --set-config liveviewsize=0 --capture-movie | ffmpeg -i - -vf format=yuv420p -f v4l2 /dev/video9

Verify that the loopback video device is working as intended with:

ffplay /dev/video9

If a window showing the live footage captured by the camera appears, the camera is now ready to be used as a webcam.

💡 Tip

If other applications fail to find the loopback video device, or fail to read the video stream, try restarting WirePlumber:

systemctl --user restart wireplumber

References

https://wiki.archlinux.org/title/V4l2loopback#Using_a_photo_camera_as_webcam_with_gPhoto

https://wiki.archlinux.org/title/GPhoto

https://wiki.archlinux.org/title/GPhoto#Claimed_device

https://askubuntu.com/questions/993876/gphoto2-could-not-claim-the-usb-device

https://www.youtube.com/watch?v=s_Fva7T3l4I

https://github.com/v4l2loopback/v4l2loopback#options

https://bugzilla.mozilla.org/show_bug.cgi?id=2007675

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