11.3 Webcams

This section describes how to configure a camera for a FreeBSD system.

Video for Linux 2 (V4L2) is the second generation of V4L. V4L2 is the kernel driver framework for video devices in the Linux kernel.

FreeBSD requires the following tools to access and configure cameras:

Port	Description
multimedia/webcamd	A daemon ported from Linux USB webcam and DVB drivers, supporting hundreds of different USB cameras and DVB USB devices
multimedia/pwcview	Can be used to view camera video streams
multimedia/mpv	Can also be used to view camera V4L2 video streams
multimedia/v4l-utils	Used for configuring and testing Video4Linux devices

Installing Camera Software

To install the required utilities using pkg, run:

# pkg install webcamd pwcview mpv v4l-utils

Install using Ports:

# cd /usr/ports/multimedia/webcamd && make install clean
# cd /usr/ports/multimedia/pwcview && make install clean
# cd /usr/ports/multimedia/mpv && make install clean
# cd /usr/ports/multimedia/v4l-utils && make install clean

Service Management

Enable the webcamd service so it starts automatically at system boot:

# service webcamd enable

Restart the device state service:

# service devd restart

User Management

The user must belong to the webcamd group. To add user ykla to the webcamd group, run the following command:

# pw groupmod webcamd -m ykla

Getting the Camera List

After installing these tools, you can use webcamd to display the list of available cameras:

# webcamd -l

The output should look similar to the following:

webcamd [-d ugen1.2] -N Jieli-Technology-USB-Composite-Device -S unknown -M 0

An available camera "Jieli-Technology-USB-Composite-Device" has been found.

Test the camera temporarily:

$ webcamd -d ugen1.2

Keep it running in the foreground for subsequent configuration.

Device files /dev/video0 and /dev/video1 will be generated.

Viewing Camera Configuration

Use the v4l2-ctl tool to list the parameters supported by the camera:

$ v4l2-ctl --list-formats-ext -d /dev/video0

ioctl: VIDIOC_ENUM_FMT

        Type: Video Capture



        [0]: 'MJPG' (Motion-JPEG, compressed)

                Size: Discrete 1920x1080

                        Interval: Discrete 0.033s (30.000 fps)

                        Interval: Discrete 0.040s (25.000 fps)

                Size: Discrete 1280x720

                        Interval: Discrete 0.033s (30.000 fps)

                        Interval: Discrete 0.040s (25.000 fps)

                Size: Discrete 640x480

                        Interval: Discrete 0.033s (30.000 fps)

                        Interval: Discrete 0.040s (25.000 fps)

                Size: Discrete 640x360

                        Interval: Discrete 0.033s (30.000 fps)

                        Interval: Discrete 0.040s (25.000 fps)

                Size: Discrete 352x288

                        Interval: Discrete 0.033s (30.000 fps)

                        Interval: Discrete 0.040s (25.000 fps)

        [1]: 'YUYV' (YUYV 4:2:2)

                Size: Discrete 640x480

                        Interval: Discrete 0.033s (30.000 fps)

                Size: Discrete 640x360

                        Interval: Discrete 0.033s (30.000 fps)

                Size: Discrete 352x288

                        Interval: Discrete 0.033s (30.000 fps)

                Size: Discrete 320x240

                        Interval: Discrete 0.033s (30.000 fps)

The above output lists in detail the video formats, resolutions, and frame rates (FPS) at different resolutions supported by this camera.

Checking the Camera

Checking the Camera with multimedia/pwcview

You can use multimedia/pwcview to check whether the camera is working properly.

Temporarily disable SDL's Xv hardware acceleration to avoid unexpected situations such as a black screen. If the test passes, this environment variable can be removed.

$ export SDL_VIDEO_YUV_HWACCEL=0

Run pwcview again (resolution 1600x1200@30fps):

$ pwcview -f 30 -s uxga

After this, multimedia/pwcview will display the camera image:

Camera Image Displayed by pwcview

Checking the Camera with mpv

You can use multimedia/mpv to check whether the camera is working properly.

$ mpv av://v4l2:/dev/video0 --vo=x11

The above command uses --vo=x11 to disable hardware acceleration and avoid unexpected situations. If the test passes, this parameter can be removed.

After this, multimedia/mpv will display the camera image:

Camera Image Displayed by mpv

Permanently Configuring the Camera

After confirming that the camera is working properly, you can make the above configuration permanent.

Configure the available camera by running the following command:

# sysrc webcamd_0_flags="-d ugen1.2"

Note

If this is a plug-and-play USB camera, the output of webcamd -l (especially the device identifier) will change after the USB port it is connected to changes, and /etc/rc.conf may need to be updated accordingly.

You must start the webcamd service by running the following command:

# service webcamd restart

The output should look similar to the following:

Starting webcamd.
webcamd 2652 - - Attached to ugen1.2[0]

Testing the Camera Online

Use a "Webcam Test" website to test the camera online: https://www.onlinemictest.com/webcam-test.

Online Camera Test Display