title: OpenCV VideoWriter does not open
body: <p>Running Windows 7, x64 with OpenCV 2.4.8 (pre-built binaries).</p>
  
  <p>Trying the following basic code:</p>
  
  <pre><code>VideoWriter wrt;
  wrt.open("video.mp4",  -1, 29, Size(480, 640));
  </code></pre>
  
  <p>This does nothing. The expected popup for codec selection does not open, nor is the writer getting open (i.e. a call to <code>wrt.isOpen()</code> returns false). Also, the internal pointer inside the writer class <code>wrt.writer</code> remains null.</p>
  
  <p>Tried:</p>
  
  <ol>
  <li>Both Debug and Release OpenCV binaries.</li>
  <li>Copying <code>opencv_ffmpeg248.dll</code> to the executable's directory according to <a href="https://stackoverflow.com/questions/17573919/videowriter-not-working-on-win7-64bit-vm">this</a>.</li>
  <li>Passing exclusive codec codes such as <code>CV_FOURCC('M','P','4','2')</code> and others.</li>
  <li>Hitting the computer.</li>
  </ol>
  
  <p>Nothing worked. Any help/direction would be appreciated..</p>