title: how to explain this C language code from ffmpeg remuxing
body: <p>can someone help me what the meaning of this code? this is a code from ffmpeg remuxing code.</p>
  
  <pre><code>static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag, int hours, int mins, int secs, int us, int *time )
  {
      AVRational *time_base = &amp;fmt_ctx-&gt;streams[pkt-&gt;stream_index]-&gt;time_base;
      total = total + pkt-&gt;duration;
    //  printf( "%d:%d:%d.%d \n", hours,  mins,  secs, us );
      *time = av_q2d(*time_base) * pkt-&gt;pts ;
  }
  </code></pre>
  
  <p>I'm kind of new to C language. thank you!</p>