Webcam

This article is a stub. Please help out by expanding it - how to get started.

Resources

Wikipedia

This article has some todo items:

Check kernel options

This article will provide information on setting up and using a webcam on Gentoo using v4l-utils.

Installation

Kernel

KERNEL Enable Webcam support

Device Drivers --->
 LED Support --->
 {*} LED Class Support Search for <code>CONFIG_LEDS_CLASS</code> to find this item.
 <*> LED Flash Class Support Search for <code>CONFIG_LEDS_CLASS_FLASH</code> to find this item.
 <*> Multimedia support Search for <code>CONFIG_MEDIA_SUPPORT</code> to find this item. --->
 [*] Filter media drivers Search for <code>CONFIG_MEDIA_SUPPORT_FILTER</code> to find this item.
 Media device types --->
 [*] Cameras and video grabbers Search for <code>CONFIG_CAMERA_SUPPORT</code> to find this item.
 Video4Linux options --->
 <M> V4L2 flash API for LED flash class devices Search for <code>CONFIG_V4L2_FLASH_LED_CLASS</code> to find this item.
 Media drivers ---> 
 [*] Media USB Adapters Search for <code>CONFIG_MEDIA_USB_SUPPORT</code> to find this item. ---> 
 <M> USB Video Class (UVC) Search for <code>CONFIG_USB_VIDEO_CLASS</code> to find this item.
 [*] UVC input events device support Search for <code>CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV</code> to find this item.

Note
To enable sound on webcams equipped with a microphone, separate options, such as "USB Audio/MIDI driver" (CONFIG_SND_USB_AUDIO), may need to be configured.

USE flags

Recommended USE flags for v4l include: qt6 - at least qt6 will be needed to follow on with this article.

USE flags for media-libs/libv4l v4l-utils libraries and optional utilities

+utils Build the v4l-utils collection of utilities

bpf Enable support for IR BPF decoders

doc Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally

dvb Add support for DVB (Digital Video Broadcasting)

jpeg Add JPEG image support

qt6 Add support for the Qt 6 application and UI framework

tracer Build the v4l2-tracer tool and library

Data provided by the Gentoo Package Database · Last update: 2025年12月19日 09:51 More information about USE flags

Emerge

Install media-libs/libv4l :

root #emerge --ask media-libs/libv4l

Additional software

There are several webcam viewer applications in the Gentoo ebuild repository, a few examples are:

Name	Package	Description
Cheese	media-video/cheese	Cheesy program to take pictures and videos from a webcam.
guvcview	media-video/guvcview	Simple Qt6 or GTK+3 interface for capturing and viewing video from v4l2 devices.
kamoso	kde-apps/kamoso	Application to take pictures and videos from a webcam, by KDE.
Motion	media-video/motion	Software motion detector.

Media players like VLC or mpv may be used to view or sometimes record video from a webcam. Most webcams are recognized and accessible through a device in /dev/video0, wherein the number in the name indicates which webcam it is, in this case the first one. Thus reading from the /dev/video0 device with the video player of your choice, will give you the image of your webcam.

See media-video for more video software.

Configuration

v4l-utils is used here to check/set the camera's preferences.

Configuration GUI and settings test

Launch the v4l GUI:

user $qv4l2

Note
The availability of qv4l2 depends on the qt6 flag for the media-libs/libv4l package.

Get settings from video device

Example of using the video4linux control application to display supported video formats:

user $v4l2-ctl --list-formats-ext

Settings example

Some cheap USB cameras (like integrated models in ThinkPad laptops) default to a 640x480 resolution even when they are capable of higher resolutions. It is possible to override this with v4l2-ctl:

user $v4l2-ctl --set-parm=30 --set-fmt-video=width=1280,height=720,pixelformat=MJPG --device /dev/video0

Explanation

--set-parm = Framerate (integer)

--set-fmt-video = Resolution + Compression

Check settings

Launch the v4l2 video capture viewer to test if the settings are working:

user $qvidcap

Note
The availability of qvidcap depends on the qt6 flag for the media-tv/v4l-utils package.

Make options persistent

Getting device info:

root #lsusb | grep Cam

Bus 003 Device 007: ID 5986:0268 Acer, Inc SunplusIT INC. Integrated Camera

Creating a rule:

FILE /etc/udev/rules.d/99-v4linux.rulesExample udev rule

SUBSYSTEM=="video4linux", SUBSYSTEMS=="usb", ATTRS{idVendor}=="5986", ATTRS{idProduct}=="0268", PROGRAM="/usr/bin/v4l2-ctl --set-parm=30 --set-fmt-video=width=1280,height=720,pixelformat=MJPG --device /dev/%k"