title: Get number of frames in clip with Moviepy
body: <p>You would think this would be such a simple operation, but there is nothing in the documentation about how to get the number of frames in a video clip. The only way I can think of is to use <code>iter_frames()</code> and just count the frames out one by one, but for some reason it takes almost a full second to iterate through 15 frames of video, even if i'm not performing any action on them.</p>