func: static void av_build_index_raw(AVFormatContext *s)
  
  {
  
      AVPacket pkt1, *pkt = &pkt1;
  
      int ret;
  
      AVStream *st;
  
  
  
      st = s->streams[0];
  
      av_read_frame_flush(s);
  
      url_fseek(&s->pb, s->data_offset, SEEK_SET);
  
  
  
      for(;;) {
  
          ret = av_read_frame(s, pkt);
  
          if (ret < 0)
  
              break;
  
          if (pkt->stream_index == 0 && st->parser &&
  
              (pkt->flags & PKT_FLAG_KEY)) {
  
              add_index_entry(st, st->parser->frame_offset, pkt->dts, 
  
                              AVINDEX_KEYFRAME);
  
          }
  
          av_free_packet(pkt);
  
      }
  
  }
  