vloopback

vloopback is a video4linux driver providing video pipes.
With the driver you can use the output of a user program to feed a program that
would normally communicate with a video4linux device.

http://www.lavrsen.dk/twiki/bin/view/Motion/VideoFourLinuxLoopbackDevice

http://bugs.gentoo.org/show_bug.cgi?id=111750

Read the readme :)

From the ebuild :

einfo "Using:"
einfo "# modprobe vloopback dev_offset=1"
einfo "# vresize /dev/video0 /dev/video1 320x240 176x144 rgb24"


http://camorama.fixedgear.org/
http://www.infinicode.org/code/cameramonitor/index.php