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Configure a 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.

First, connect your camera to your machine’s computer (unless it is built-in like a webcam on a laptop) and power both on. Then, configure your camera:

Navigate to the CONFIGURE tab of your machine’s page in the Viam app. Click the + icon next to your machine part in the left-hand menu and select Component. Select the camera type, then select the webcam model. Enter a name or use the suggested name for your camera and click Create.

Configuration of a webcam camera in the Viam app config builder.

Edit and fill in the attributes as applicable. If you click on Show more, then the video_path field while your machine is live, a dropdown autopopulates with identified camera paths.

{
  "name": "<your-camera-name>",
  "model": "webcam",
  "type": "camera",
  "namespace": "rdk",
  "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",
  "type": "camera",
  "namespace": "rdk",
  "attributes": {
    "video_path": "video0"
  }
}

The following attributes are available for webcam cameras:

Name	Type	Required?	Description
`video_path`	string	Optional	The 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`.
`format`	string	Optional	The camera image format, used with `video_path` to find the camera. See Using `format`.
`width_px`	int	Optional	The 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_px`	int	Optional	The 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_rate`	float	Optional	The 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_parameters`	object	Optional	The 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_parameters`	object	Optional	Modified 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`

To list available video_paths use the following command:

Linux
Mac

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.

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 the Viam app, 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

View the camera stream

Once your camera is configured and connected, expand the TEST panel on the CONFIGURE or CONTROL tabs. If everything is configured correctly, you will see the live feed from your camera.

Troubleshooting

If your camera is not working as expected, follow these steps:

Check your machine logs on the LOGS tab to check for errors.
Review this camera model’s documentation to ensure you have configured all required attributes.
Click on the TEST panel on the CONFIGURE or CONTROL tab and test if you can use the camera there.

If none of these steps work, reach out to us on the Community Discord and we will be happy to help.

Common errors

Failed to find the best driver that fits the constraints

When working with a camera component, depending on the camera, you may need to explicitly provide some camera-specific configuration parameters.

Solution: Check the specifications for your camera, and manually provide configuration parameters such as width and height to the camera component configuration page on the Viam app. On the CONFIGURE page, find your camera, then fill in your camera’s specific configuration either using the Show more button to show the relevant configuration options, or the {} (Switch to Advanced) button in the top right of the component panel to enter these attributes manually. Provide at least the width and height values to start.

Cannot open webcam or found no webcams

When working with a camera component 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 the Viam Rover appears 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 supported by Viam. 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.

No visible live video feed

If you’re working on a Linux machine, ssh into it, then restart viam-server by running:

sudo systemctl restart viam-server

If this doesn’t work, you can reboot your machine by running:

sudo reboot

Images are dim on start up

If you are capturing camera data, it can happen that the camera captures and syncs miscolored or dark images upon start up.

CSI Camera not working on a Raspberry Pi

If you are using a CSI camera v1.3 or v2.0 on a Raspberry Pi, you need to enable legacy mode. If you are using a CSI camera v3.0, you need to use the viam:camera:csi module instead.

High CPU usage

Each camera stream you add uses CPU on the device it is connected to and there is therefore a practical limit to the numbeof camera streams your device can simultaneously support. You can limit the CPU usage by reducing the image resolution.

Timeout errors on a Raspberry Pi

If you are getting “timeout” errors from GRPC when adding a webcam model on a Raspberry Pi, make sure the webcam port is enabled on the Pi (common if you are using a fresh Pi right out of the box).

To enable the webcam port on a Raspberry Pi, run the following command:

sudo raspi-config

Then, select: Interface Options -> Camera -> Enable Camera.

Restart the Pi to complete the configuration.

Next steps

For more configuration and usage info, see:

Have questions, or want to meet other people working on robots? Join our Community Discord.

If you notice any issues with the documentation, feel free to file an issue or edit this file.

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