title: How to find SPS and PPS string in H264 codec from mp4
body: <p>As you all know that in Smooth Stream client manifest file, contains a "CodecPrivateData" attribute in video tag. Now after my initial investigation I found that this string is formed by using SPS and PPS which are essentially NAL units.</p>
  
  <p>I am looking for a way to extract that information from video GOP, so that I can use the same to create manifest file and manually substitute codec private data</p>
  
  <p>Basically, i am looking forward to create custom app to create smooth representation using ffmpeg</p>