title: iOS AVFoundation Video overlay Video issues
body: <p>I having been crunching on the avfoundation framework for a few days now.  I am ale to successfully overlay and position CALayers and mash, export the final video with the exporter session.  </p>
  
  <p>I need to have a video with alpha transparency OVERLAY another video for the duration of the the video asset.  I cannot get this to work AT ALL.  Any help would rock!</p>