A framework for drivers of video cameras, TV tuners etc. The device API for userland processes is commonly called v4l or v4l2 (v4l being deprecated in theory). DeviceDrivers written for this framework are normally compiled into the LinuxKernel as Modules. The devices are enumerated by UDev and appear as /dev/video0, /dev/video1 etc.

You must have the videodev Module loaded as well.

Some applications require a specific device name e.g. /dev/video, although this is probably not the desired behaviour and these apps will probably be modified in the future. If you are using an application that wants a /dev/video but your system only has a /dev/video0 then you need to make a symbolic link. The proper way to do this is with UDev. Create (or modify) a file called 00_video4linux.rules in the /etc/udev/rules.d directory, with the following content:

# make a symlink to the first radio device
KERNEL="video0",        SYMLINK="video"

Also known as V4L.