title: no video with supported format and MIME type found. What does this mean and how can I change this
body: <p>no video with supported format and MIME type found</p>
  
  <p>A huge screen for video is displayed and says the message above. How do I solve this?
  This happens to me only in Mozilla Fire fox and not on Google Chrome. I am using webm videos and mp4 videos.</p>
  
  <p>This is for html5 video.</p>