How to use a camera with OpenCV

Question

I'm trying to learn OpenCV. I have been playing around with it for an entire day trying to get it to recognize my camera. I just can't get it to work and I can't find any information about it.

My camera is a usb xbox live webcam, as soon as I connected it to my computer windows recognized it as if it were its own child and installed the drivers.

DISCLAIMER I'm like completely clueless as I have never worked with cameras before in code and I don't know how hard or difficult it would be to use one, nor do I know where to start, what information to look up, or anything like that. :( DISCLAIMER

I found this example on the opencv website at this url: http://opencv.willowgarage.com/wiki/CameraCapture

I copy and pasted the first one which says "Here is a simple framework to connect to a camera and show the images in a Window.". I formatted it correctly and got it to compile and run perfectly, but it gives the error "ERROR: capture is NULL" when I execute it(not a compiler error, its an error in the application)

Answer 1

I think there are more than enough code on stackoverflow that shows how to do the trick:

OpenCV 2.1: Runtime error

Unable to detect web cam in OpenCV

OpenCV: process every frame

OpenCV 'cvQueryFrame' non-blocking on OS X?