title: Frames aren't written to video using opencv
body: <p>I'm trying to create a program that exports frames into a video file.
  I'm using C.</p>
  
  <p>I have an array of IplImage* (IplImage** images) which contains all the frames that I want to export into a video.
  However, the video that comes out is always blank (with no frames and the duration is 0:00).
  Here is the part of my code thta I think I made wrong (size is the size of the images array):</p>
  
  <pre><code>CvVideoWriter* vWriter = cvCreateVideoWriter(path, CV_FOURCC('N', 'A', 'V', 'I'), 50, cvSize(maxWidth, maxHeight), 1);
  for (i = 0; i &lt; size; i++)
  {
      cvWriteFrame(vWriter, images[i]);
  }
  cvReleaseVideoWriter(&amp;vWriter);
  free(images);
  </code></pre>
  
  <p>The video that is created is empty, instead of having all of the frames of the array IplImage** images in it</p>
  
  <p>Edit: It's kind of an assigment (more like a bonus), and I have to user C.
  If I use c++ it doesn't count.</p>