title: FFMPEG record http video stream with normal speed
body: <p>I'm recording an http stream from my IP Camera (TPLINK NC200), using this command:</p>
  
  <pre><code>ffmpeg -i http://admin:YWRtaW4=@192.168.0.18:8080/stream/getvideo -t 30 -acodec copy -vcodec copy abc.mp4
  </code></pre>
  
  <p>As you can see , the video length is set to 30 seconds ( -t option ) . But it takes about 1 minute 30 seconds to record , and the video speed is very high ( the camera recording a stopwatch and a 30-second video recorded the timer to 1 minute and 11 seconds ).</p>
  
  <p>Is there some ffmpeg option to get a normal speed video? Or the problem is the camera configuration? </p>