webcam

webcam is the general camera model. If the camera drivers are among those in this mediadevices repository, the camera will work with the webcam model.

Configuration

{
  "name": "<your-camera-name>",
  "model": "webcam",
  "api": "rdk:component:camera",
  "attributes": {
    "intrinsic_parameters": {
      "width_px": <int>,
      "height_px": <int>,
      "fx": <float>,
      "fy": <float>,
      "ppx": <float>,
      "ppy": <float>
    },
    "distortion_parameters": {
      "rk1": <float>,
      "rk2": <float>,
      "rk3": <float>,
      "tp1": <float>,
      "tp2": <float>
    },
    "format": <string>,
    "video_path": "<your-video-path>",
    "width_px": <int>,
    "height_px": <int>,
    "frame_rate": <float>
  }
}

{
  "name": "my_cam",
  "model": "webcam",
  "api": "rdk:component:camera",
  "attributes": {
    "video_path": "video0"
  }
}

Attributes

NameTypeRequired?Description
video_pathstringOptionalThe ID of or the path to the webcam. If you don’t provide a video_path, it defaults to the first valid video path it finds. Using the ID of a webcam is more consistent than the path. See Using video_path.
formatstringOptionalThe camera image format, used with video_path to find the camera. See Using format.
width_pxintOptionalThe camera image width in pixels, used with video_path to find a camera with this resolution. Negative values are silently ignored and result in the default being used.
Default: Closest possible value to 480
height_pxintOptionalThe camera image height in pixels, used with video_path to find a camera with this resolution. Negative values are silently ignored and result in the default being used.
Default: Closest possible value to 640
frame_ratefloatOptionalThe camera capture frequency as frames per second, used with video_path to find a camera with this throughput.
Default: Closest possible value to 30.0
intrinsic_parametersobjectOptionalThe intrinsic parameters of the camera used to do 2D <-> 3D projections:
  • width_px: The expected width of the aligned image in pixels.
  • height_px: The expected height of the aligned image in pixels.
  • fx: The image center x point.
  • fy: The image center y point.
  • ppx: The image focal x.
  • ppy: The image focal y.
distortion_parametersobjectOptionalModified Brown-Conrady parameters used to correct for distortions caused by the shape of the camera lens:
  • rk1: The radial distortion x.
  • rk2: The radial distortion y.
  • rk3: The radial distortion z.
  • tp1: The tangential distortion x.
  • tp2: The tangential distortion y.

Using video_path

Find a video path using a discovery service

The viam:find-webcams:webcam-discovery service helps you identify path options. To add and use the service:

  1. Navigate to the CONFIGURE tab of your machine’s page.
  2. Click the + icon next to your machine part in the left-hand menu and select Service.
  3. Search for find-webcams and select the discovery / find-webcams:webcam-discovery service.
  4. Click Add module.
  5. Enter a name or use the suggested name for your camera and click Create.
  6. Save your configuration, and wait a moment for the service to start.
  7. Click Test to see the available video_paths.
  8. Click the Copy attributes button for the camera you want to use.
  9. Click the {} icon in the upper right corner of the camera component configuration.
  10. Paste the copied attributes.
  11. Click Save.
  12. You can now delete the discovery service and the module that provides it from your machine.

Find a video path using the command line

To list available video_paths use the following command:

ls /dev/v4l/by-id/

To find the paths of all connected video devices, run the following command:

v4l2-ctl --list-devices

The id listed by ls /dev/v4l/by-id/ is a more consistent way to refer to the webcam.

system_profiler SPCameraDataType

The Unique ID displayed for each camera is the video_path.

If you are using macOS version 15.x.x Sequoia or later, you need to give viam-server permissions to access webcams. When you run viam-server for the first time, a pop-up message will ask for camera access. Click Allow. To confirm settings, you can go to System Settings > Privacy & Security > Camera and check that the toggle next to viam-server is set to enable access.

Using format

Viam supports the following pixel formats:

  • I420
  • I444
  • MJPEG / MJPG
  • NV12
  • NV21
  • RGBA
  • UYVY / Y422
  • YUY2 / YUYV / V422
  • Z16

If your machine is connected to Viam, the available pixel formats supported by your camera automatically appear in the Format dropdown menu, which is visible when you click the Show more button.

On Linux, you can also manually determine which pixel formats your camera supports by running the following command on the machine your camera is connected to. Replace /dev/video0 with the video path you determined for your video device above, if different:

v4l2-ctl --list-formats-ext --device /dev/video0

Troubleshooting

Cannot open webcam or found no webcams

When working with a webcam camera on the Linux platform, your Linux OS must be able to access the camera properly, and the camera must be configured to use a pixel format that Viam supports.

On your Linux system, verify each of the following:

  • Ensure that your Linux OS is able to access your camera:

    1. Run the following command to list compatible camera devices on your system:

      v4l2-ctl --list-devices

      In the list of camera devices returned, find the entry for your camera. For example, the webcam on a rover may appear as follows:

      GENERAL WEBCAM: GENERAL WEBCAM (usb-0000:01:00.0-1.4):
        /dev/video0
        /dev/video1
        /dev/media4

      The video path for your camera device is the first path listed under that camera, in this case /dev/video0.

    2. Then, stop viam-server, and verify that your Linux OS is able to access that video device properly:

      v4l2-ctl --stream-count 1 --device /dev/video0

      Replace /dev/video0 in the above command with the video path you determined for your video device above, if different.

      The command returns successfully (with no output) if Linux is able to successfully communicate with the camera, or errors with Cannot open device if there was a problem communicating. If this command errors, you should consult the documentation for your camera and Linux distribution to troubleshoot. If you receive the error Device or resource busy instead, be sure you have stopped viam-server first, then re-run the command above.

  • Ensure that your camera uses a supported pixel format:

    1. First, determine your video path, like /dev/video0, following the instructions above.

    2. Then, run the following command:

      v4l2-ctl --list-formats-ext --device /dev/video0

      Replace /dev/video0 in the above command with the video path you determined for your video device above, if different.

      The command will return a list of pixel formats your camera supports, such as MJPG (also notated as MJPEG) or YUYV (also notated as YUY2). In order to use a camera device with Viam, it must support at least one of the pixel formats listed in Using format. If your camera does not support any of these formats, it cannot be used with Viam.

If you are still having issues with your camera component on the Linux platform, and would like to file an issue, include your machine’s camera debug file contained in the /root/.viam/debug/components/camera directory. If you are running viam-server as a different user, find the .viam/debug/components/camera directory in that user’s home directory instead. This file contains basic diagnostic and configuration information about your camera that helps to quickly troubleshoot issues.

macOS camera permissions issues

On macOS, if you’re having trouble accessing your webcam, you may need to grant camera permissions for the application that you use to run viam-server.

Resetting camera permissions:

If viam-server is not prompting for camera permissions or you need to re-grant permissions, you can reset the camera permissions for all applications using the following command:

tccutil reset Camera

If you know the macOS bundle ID of the application that you use to run viam-server, you can pass the bundle ID to limit the camera permissions reset to only that application. For instance, you can reset camera permissions for the built-in Terminal app with tccutil reset Camera com.apple.Terminal. If the command was successful, you should see output similar to the following:

Successfully reset Camera approval status for com.apple.Terminal

After running this command, restart viam-server and it should prompt for camera permissions again.

Checking camera permissions:

To verify camera permissions, go to System Settings > Privacy & Security > Camera. Find the application viam-server is running in (such as Terminal or VS Code). Ensure that your terminal application has camera access enabled.