func: static int mxf_get_stream_index(AVFormatContext *s, KLVPacket *klv)
  
  {
  
      int i;
  
  
  
      for (i = 0; i < s->nb_streams; i++) {
  
          MXFTrack *track = s->streams[i]->priv_data;
  
          /* SMPTE 379M 7.3 */
  
          if (!memcmp(klv->key + sizeof(mxf_essence_element_key), track->track_number, sizeof(track->track_number)))
  
              return i;
  
      }
  
      /* return 0 if only one stream, for OP Atom files with 0 as track number */
  
      return s->nb_streams == 1 ? 0 : -1;
  
  }
  