title: How to determine number of frames using vision.VideoFileReader
body: <p>I've got a video, how could I determine number of frames in the video using matlab built-in function - <code>vision.VideoFileReader</code>? </p>
  
  <p>It is not the same as VideoReader which I can get the number of frames by : </p>
  
  <pre><code>vidObj = VideoReader('varFrameRateFile.wmv');
  numFrames = vidObj.NumberOfFrames;
  </code></pre>