title: opencv imshow with waitKey too slow on Mac OS X 10.10.2 (using c++)
body: <p>I am using opencv c++ on Mac OS X 10.10.2 to process video frames and display them. The performance of imshow with waitKey to display the video is extremely slow.</p>
  
  <p>I have the following code which displays HD (1920x1080) grayscale frames correctly, except that it runs about 10 times too slow (i.e. 2 to 3 frames per second instead of 30 frames per second).</p>
  
  <pre><code>          cv::Mat framebuf[TEST_COUNT];
  
      //--- Code here to allocate and fill the frame buffer with about 4 seconds of video. This part works correctly.
  
          //--- This loop runs too slow by factor of approximately 10x
      for (int f = 0; f &lt; TEST_COUNT; f++)
      {
          cv::imshow(windowName, framebuf[f]);
          cv::waitKey(33);
      }
  </code></pre>
  
  <p>Can anyone suggest how to get real-time or near real-time performance from opencv imshow()? I have seen many posts that state that they are displaying video in real-time or even faster than real-time, so I am not sure what I am doing wrong. Any help would be greatly appreciated.</p>