How to use the command 'uvcdynctrl' (with examples)

UVCDynCtrl is a libwebcam command-line tool that allows users to manage the dynamic controls in uvcvideo. It provides various options to list the available cameras, specify a device to use, list available controls, set control values, get the current control value, save and load the state of controls from a file. This article will illustrate each of these use cases with examples.

Use case 1: List all available cameras

Code:

uvcdynctrl -l

Motivation: This use case allows users to list all available cameras connected to the system. It can be helpful in identifying the camera device names and choosing the correct device for further configuration.

Explanation: The -l option is used to list all available cameras.

Example output:

Listing available devices:
    /dev/video0
    /dev/video1
    /dev/video2

Use case 2: Specify the device to use

Code:

uvcdynctrl -d device_name

Motivation: By default, UVCDynCtrl uses the video0 device. This option allows users to specify a different device to work with.

Explanation: The -d option is used to specify the device to use. Replace device_name with the desired device name.

Example output: No output. This command only sets the active device for further actions.

Use case 3: List available controls

Code:

uvcdynctrl -c

Motivation: This use case provides a list of available controls supported by the connected camera. It can be used to explore the available controls and their names for further configuration.

Explanation: The -c option is used to list available controls.

Example output:

Listing available controls:
    Brightness
    Contrast
    Saturation
    ...

Use case 4: Set a new control value

Code:

uvcdynctrl -s control_name value

Motivation: This use case allows users to set a new value for a specific control of the connected camera. It can be used to adjust various parameters such as brightness, contrast, saturation, etc.

Explanation: The -s option is used to set a new control value. Replace control_name with the name of the control and value with the desired value. For negative values, use -- -value.

Example output: No output. This command only sets the new control value.

Use case 5: Get the current control value

Code:

uvcdynctrl -g control_name

Motivation: This use case retrieves the current value of a specific control of the connected camera. It can be used to check the current settings or for further analysis.

Explanation: The -g option is used to get the current control value. Replace control_name with the name of the control.

Example output:

Current value of Brightness control: 128

Use case 6: Save the state of the current controls to a file

Code:

uvcdynctrl -W filename

Motivation: This use case allows users to save the current state of all controls to a file. It can be useful for backing up the current camera settings or for later restoration.

Explanation: The -W option is used to save the state of the current controls to a file. Replace filename with the desired file name.

Example output: No output. This command only saves the state of controls to the specified file.

Use case 7: Load the state of the controls from a file

Code:

uvcdynctrl -L filename

Motivation: This use case allows users to load the state of controls from a previously saved file. It can be used to restore previously saved camera settings.

Explanation: The -L option is used to load the state of the controls from a file. Replace filename with the name of the file containing the saved control state.

Example output: No output. This command only loads the state of controls from the specified file.

Conclusion:

UVCDynCtrl provides a powerful command-line interface to manage dynamic controls in uvcvideo. With its various options, users can easily list available cameras, specify the active device, explore available controls, set new control values, get current control values, save and load control states from files. By understanding and utilizing the functionality provided by UVCDynCtrl, users can efficiently configure and adjust their connected cameras according to their requirements.