> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/ask/flat/chapter-11-multimedia-and-external-devices/di-11.3-jie-she-xiang-tou.md). # 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: ```sh # pkg install webcamd pwcview mpv v4l-utils ``` Install using Ports: ```sh # 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: ```sh # service webcamd enable ``` Restart the device state service: ```sh # 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: ```sh # pw groupmod webcamd -m ykla ``` ## Getting the Camera List After installing these tools, you can use webcamd to display the list of available cameras: ```sh # webcamd -l ``` The output should look similar to the following: ```sh 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: ```sh $ 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: ```sh $ 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. ```sh $ export SDL_VIDEO_YUV_HWACCEL=0 ``` Run pwcview again (resolution 1600x1200\@30fps): ```sh $ pwcview -f 30 -s uxga ``` After this, multimedia/pwcview will display the camera image: ![Camera Image Displayed by pwcview](/files/A3uLs4HTryqTHRaCwafK) ### Checking the Camera with mpv You can use multimedia/mpv to check whether the camera is working properly. ```sh $ 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](/files/cHCKTe90H7a87LxyG3b5) ## 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: ```sh # 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: ```sh # service webcamd restart ``` The output should look similar to the following: ```sh Starting webcamd. webcamd 2652 - - Attached to ugen1.2[0] ``` ## Testing the Camera Online Use a "Webcam Test" website to test the camera online: . ![Online Camera Test Display](/files/sntFcyW3xyby9hlJ5Jcm) --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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