title: How to find keyframe in MPEG-2 stream, packed in MPEG-TS
body: <p>I've written MPEG-TS demuxer. It unpacks transport stream to PES packets.
  Now I want to drop all frames till I meet keyframe.</p>
  
  <p>How can I do it? Should I find for Sequence block in each PES frame?</p>