title: How to set Buffered flv file metadata
body: <p>I have flv file on my server. duration is 9 minutes.
  I have to extract 30 seconds from this flv. I'm reading  the 30 second exact bytes from my source file and stream it to the client.
  My problem is that when file is downloaded it, my gom player still showed that file is 9 minute but it has content of 30 seconds. how can I change this metadata during buffering.</p>
  
  <p>My coding language is C#</p>
  
  <p>Thanks</p>