title: Timestamp information of MP4
body: <p>I want to ask for an easy way to get the timestamp information of a mp4 file. (Sorry that I am not familiar with codec.) </p>
  
  <p>I am reading the Tobii Pro Glasses SDK document that explains how to synchronize frame with eye tracking data, where they use a terminorlogy called VTS. Goolge cannot find the exact meaning, so I want to ask for what VTS really stands for and how to get it from a mp4 file. Thanks very much! </p>