One thing OpenWRT can do (if you run it on a router with USB ports) is stream video from a webcam using mjpg-streamer. Pretty useful if you want to put a webcam in some random place.
(The current version of OpenWRT, backfire, needs additional nondefault packages involved: see http://blog.bashroom.com/2010/05/04/webcam-streaming-with-openwrt-backfire/.)
I tried this with an old webcam I had lying around, but the old webcam predated the UVC (USB Video Class) standard, and I couldn’t get it to work. So then I bought a couple of the cheapest webcams on Amazon that claimed UVC support.
Not too surprisingly, neither one worked right away — when I start mjpg- streamer as described in the abovelinked article, it would say “Unable to set format: invalid argument”. This turns out to be because these cheaper cameras don’t support MJPG in hardware, only YUV output; mjpg-streamer can convert but you have to pass -y to it.
So for OpenWRT, I edited /etc/init.d/mjpg-streamer to add -y to the —input argument.
The resulting stream is choppy, and gets backed up several frames, but is good enough for my purposes. It also spikes the router CPU to 100%, even on a newer faster router I have, so I told mjpg-streamer to stream at 1 fps, which is not that much choppier and still good enough for my purposes (edit /etc/config /mjpg-streamer to do this).
Moral of the story: it’s probably better to buy a webcam known to support MJPG in hardware.
(Thanks to https://forum.openwrt.org/viewtopic.php?pid=98294and http://arthurhong-linux.blogspot.com/2008/11/mjpgstreamer-or-uvcstreamer-always.html for helping me figure out the YUV format problem and solution.)