From Linux Man Pages
v4l - video4linux driver
SYNOPSIS
Section "Module"
...
Load "v4l"
EndSection
DESCRIPTION
v4l is an Xorg driver for video4linux cards. It provides a Xvideo extension port for video overlay. Just add
the driver to the module list within the module section of your xorg.conf file if you want to use it. There are
no config options.
Note that the the extmod module is also required for the Xvideo support (and lots of other extensions too).
SUPPORTED HARDWARE
The v4l driver works with every piece of hardware which is supported by a video4linux (kernel-) device driver and
is able to handle video overlay.
bt848/bt878-based TV cards are the most popular hardware these days.
CONFIGURATION DETAILS
Please refer to xorg.conf(5x) for general configuration details. This section only covers configuration details
specific to this driver.
RELATED
Xorg(1x), xorg.conf(5x), xorgconfig(1x), Xserver(1x), X(7)
CATEGORY