title: How do I get a list of webcam devices using opencv?
body: <p>I am using OpenCV2.2 with videoInput.  I want to upgrade to OpenCV2.3.1 where videoInput has apparently been merged into OpenCV2.3.</p>
  
  <p>My problem is that there doesn't appear to be a listdevices() function to return all the video sources available.</p>
  
  <p>Does anybody know the new equivalent? </p>