Camera Troubleshooting

Pi Cameras

If you haven’t yet, please refer to the Pi CSI Camera Configuration page for information on updating config.txt for your use case. If you’ve tried that, and things still aren’t working, restart PhotonVision using the restart button in the settings tab, and press tilde (`) in the web UI once connection is restored. This should show the most recent boot log.

	Expected output	Bad
LibCamera driver initialization	Successfully loaded libpicam shared object	Failed to load native libraries!
Camera detected	Adding local video device - “unicam” at “/dev/video0”	No output from VisionSourceManager
VisionSource created	Adding 1 configs to VMM.	No output from VisionSourceManager

If the driver isn’t loaded, you may be using a non-official Pi image, or an image not new enough. Try updating to the most recent image available (one released for 2023) – if that doesn’t resolve the problem, contact us with your settings ZIP file and Pi version/camera version/config.txt file used.

If the camera is not detected, the most likely cause is either a config.txt file incorrectly set-up, or a ribbon cable attached backwards. Review the picam configuration page, and verify the ribbon cable is properly oriented at both ends, and that it is _fully_ inserted into the FFC connector. Then, contact us with your settings ZIP file and Pi version/camera version/config.txt file used.

USB cameras

USB cameras supported by CSCore require no libcamera driver initialization to work – however, similar troubleshooting steps apply. Restart PhotonVision using the restart button in the settings tab, and press tilde on your keyboard (`) when you’re in the web UI once connection is restored. We expect to see the following output:

	Expected output	Bad
Camera detected	Adding local video device - “foobar” at “/dev/foobar”	No output from VisionSourceManager
VisionSource created	Adding 1 configs to VMM.	No output from VisionSourceManager

Determining detected cameras in Video4Linux (v4l2)

On Linux devices (including Raspberry Pi), PhotonVision uses WPILib’s CSCore to interact with video devices, which internally uses Video4Linux (v4l2). CSCore, and therefore Photon, requires that cameras attached have good v4l drivers for proper functionality. These should be built into the Linux kernel, and do not need to be installed manually. Valid picamera setup (from /boot/config.txt) can also be determined using these steps. The list-devices command will show all valid video devices detected, and list-formats the list of “video modes” each camera can be in.

For picams: edit the config.txt file as described in the picam configuration page
SSH into your Pi: ssh pi@photonvision.local and enter the username “pi” & password “raspberry”
run v4l2-ctl --list-devices and v4l2-ctl --list-formats

We expect an output similar to the following. For picameras, note the “unicam” entry with path platform:3f801000.csi (if we don’t see this, that’s bad), and a huge list of valid video formats. USB cameras should show up similarly in the output of these commands.

Working

pi@photonvision:~ $ v4l2-ctl --list-devices
unicam (platform:3f801000.csi):
    /dev/video0
    /dev/media3

bcm2835-codec-decode (platform:bcm2835-codec):
    /dev/video10
    /dev/video11
    /dev/video12
    /dev/video18
    /dev/video31
    /dev/media2

bcm2835-isp (platform:bcm2835-isp):
    /dev/video13
    /dev/video14
    /dev/video15
    /dev/video16
    /dev/video20
    /dev/video21
    /dev/video22
    /dev/video23
    /dev/media0
    /dev/media1

pi@photonvision:~ $ v4l2-ctl --list-formats
ioctl: VIDIOC_ENUM_FMT
Type: Video Capture

[0]: 'YUYV' (YUYV 4:2:2)
[1]: 'UYVY' (UYVY 4:2:2)
[2]: 'YVYU' (YVYU 4:2:2)
[3]: 'VYUY' (VYUY 4:2:2)
<snip>
[42]: 'Y12P' (12-bit Greyscale (MIPI Packed))
[43]: 'Y12 ' (12-bit Greyscale)
[44]: 'Y14P' (14-bit Greyscale (MIPI Packed))
[45]: 'Y14 ' (14-bit Greyscale)

Not Working

pi@photonvision:~ $ v4l2-ctl --list-devices
bcm2835-codec-decode (platform:bcm2835-codec):
    /dev/video10
    /dev/video11
    /dev/video12
    /dev/video18
    /dev/video31
    /dev/media3
 bcm2835-isp (platform:bcm2835-isp):
    /dev/video13
    /dev/video14
    /dev/video15
    /dev/video16
    /dev/video20
    /dev/video21
    /dev/video22
    /dev/video23
    /dev/media0
    /dev/media1
rpivid (platform:rpivid):
    /dev/video19
    /dev/media2
Cannot open device /dev/video0, exiting.