title: Detect if video file contains movement
body: <p>I have a bunch of video clips from a webcam (duration is 5, 10, 60 seconds), and I'm looking for a way to detect "does this video clip have movement", to decide whether the file should be saved or discarded in a future processing phase.</p>
  
  <p>I've looked into <a href="http://www.lavrsen.dk/foswiki/bin/view/Motion/WebHome" rel="nofollow">motion</a> and <a href="http://opencv.org/" rel="nofollow">OpenCV</a>, but motion seems to only want to work on the raw video stream, and OpenCV seems to be way too advanced for my use.</p>
  
  <p>My ideal solution would be a linux command-line tool that I can feed video files into, and get a simple "does/doesn't contain movement" answer back, so I can discard the irrelevant files. False positives (in a reasonable quantity) are perfectly acceptable for my use.</p>
  
  <p>Does such a tool exist? Or any simple examples of doing this with other tools?</p>