func: static int v4l2_read_packet(AVFormatContext *s1, AVPacket *pkt)
  
  {
  
  #if FF_API_CODED_FRAME
  
  FF_DISABLE_DEPRECATION_WARNINGS
  
      struct video_data *s = s1->priv_data;
  
      AVFrame *frame = s1->streams[0]->codec->coded_frame;
  
  FF_ENABLE_DEPRECATION_WARNINGS
  
  #endif
  
      int res;
  
  
  
      av_init_packet(pkt);
  
      if ((res = mmap_read_frame(s1, pkt)) < 0) {
  
          return res;
  
      }
  
  
  
  #if FF_API_CODED_FRAME
  
  FF_DISABLE_DEPRECATION_WARNINGS
  
      if (frame && s->interlaced) {
  
          frame->interlaced_frame = 1;
  
          frame->top_field_first = s->top_field_first;
  
      }
  
  FF_ENABLE_DEPRECATION_WARNINGS
  
  #endif
  
  
  
      return pkt->size;
  
  }
  