title: How to read Timing Reference Signal/Ancillary data from a video stream?
body: <p>I’m in search for a solution that makes it possible to read the Timing Reference Signal (TRS) and Ancillary data (HANC and VANC) of a serial digital video. The TRS gives information about the start and the end of active video (SAV/EAV), the Ancillary data gives, for example, information about embedded audio. With this I want to code an application that analyzes the data that is transported in the non-picture area of serial video.</p>
  <p>I read much about <code>GStreamer</code> and found with <code>GstVideo Ancillary</code> a collection that makes it possible to handle the Ancillary Data of a video.</p>
  <p>Unfortunately, it’s not clear to me, how this collection works. For me, it looks like that this collection can only construct Ancillary data for a video and it’s not possible to read ancillary data from a detected videostream.</p>
  <p>Another idea is to read the whole video stream and display, in a first step, the data words of the stream. TRS and ANC packets have to start with a special sequence of identifiers that makes it possible to localize them. Is <code>GStreamer</code> for this the right choice? Are there better recommended libraries for this task?</p>