title: Webcam is not being detected in opencv
body: <p>I am using opencv 2.3.1a in ubuntu 11.o4. </p>
  
  <p>I installed opencv using: <a href="http://www.samontab.com/web/2011/06/installing-opencv-2-2-in-ubuntu-11-04/" rel="nofollow">http://www.samontab.com/web/2011/06/installing-opencv-2-2-in-ubuntu-11-04/</a></p>
  
  <p>Since I could not use webcam with that installation. I changed "cmake" option from WITH_V4L=OFF to WITH_V4L=ON. But it still does not work.</p>
  
  <p>I tried the following code:</p>
  
  <pre><code>#include "cv.h" 
  #include "highgui.h" 
  #include &lt;stdio.h&gt;  
  // A Simple Camera Capture Framework 
  int main() {
  CvCapture* capture = cvCaptureFromCAM( 0);
  
  if(!capture)
  {
      printf("no camera");
      return -1;
  }
  }
  </code></pre>
  
  <p>And yeah the output is : no camera
  I do not know where the problem is.</p>