title: Understanding ffmpeg re parameter
body: <p>I was reading about the <code>-re</code> option in <code>ffmpeg</code> .
  What they have mentioned is </p>
  
  <blockquote>
    <p>From the <a href="https://www.ffmpeg.org/ffmpeg.html#Advanced-options" rel="noreferrer">docs</a>  </p>
    
    <p><code>-re (input)</code>    </p>
    
    <p>Read input at the native frame rate. Mainly used to simulate a grab device, or live input stream (e.g. when reading from a file). <strong>Should not be used with actual grab devices or live input streams (where it can cause packet loss)</strong>. By default ffmpeg attempts to read the input(s) as fast as possible. This option will slow down the reading of the input(s) to the native frame rate of the input(s). <strong>It is useful for real-time output (e.g. live streaming).</strong></p>
  </blockquote>
  
  <p>My doubt is basically the part of the above description that I highlighted. It is suggested to not use the option during live input streams but in the end, it is suggested to use it in real-time output.</p>
  
  <p>Considering a situation where both the input and output are in <code>rtmp</code> format, should I use it or not?</p>