title: Key callbacks with gstreamer
body: <p>I was wondering if anyone has any idea of how to do key callbacks with gstreamer. I've looked, and can't find anything. I'm trying to do the equivalent of cvWaitKey. I do have OpenCV in my program and it can interact with Gstreamer. However, Gstreamer is outputting the video to the screen thus cvWaitKey doesn't work.
  Thanks!</p>