title: ffmpeg fix video orientation
body: <p>A video can contain a meta info about the camera orientation. For example iPhone and other phones set this flag if you turn the device. Problem is while some player read this info and rotate the video accordingly, other players do not.</p>
  
  <p>To fix this the video has to be rotated and the meta info needs to be set correctly.</p>
  
  <p>Does ffmpeg provide a fix for this or do I have to go the hard way (<a href="https://stackoverflow.com/questions/9334176/detect-orientation-of-an-iphone-video-from-server">Read rotation</a>, rotate, set meta data)</p>