Tuesday, 5 June 2012

Motion webcam two webcams change order on boot /dev/video0 persistent linux ubuntu

Copied from various resources on the web, Original Reference Here

When using Motion http://www.lavrsen.dk/foswiki/bin/view/Motion with multiple usb webcams, sometimes the dev order of the webcams changes on reboot of a machine. 

i.e.  /dev/video0 becomes dev/video1

This can seriously stuff things up.  To overcome this, create a udev rule to lock/assign a device dev location.

First do a lsusb, notice that I have two webcams, one is built into the screen and the other is USB connected.

Take note of the ID of the webcam you want
i.e 045e:00f7

Now do a:
sudo touch /etc/udev/rules.d/25-name-video-devices.rules

Edit this file and enter the following:
SUBSYSTEM=="video4linux", BUS=="usb", SYSFS{idVendor}=="045e", SYSFS{idProduct}=="00f7", NAME="video5"

I assigned the webcam to give a default location of /dev/video5 so it would never conflict with other webcams fitted in the future (hopefully)

Don't forget to modify your ~/.motion/motion.conf file and change the video device to /dev/video5

What happens if you have two webcams and they are both the same?  Fuuuuuuuuuuuuuuuuu!!!!!!!!!!!!!!!

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