title: Merge two video side by side ffmpeg
body: <p>I´m working on project android with ffmpeg who can merge two videos side by side and i have a problem for example the first video has 20 seconds and the second has 35 seconds when i merge them i got video has 35 seconds everytime video got the large time but i want the small
  in above exmaple i want the output video has 20 seconds not 35.
  my shot</p>
  
  <pre><code>"-i","firsth.mp4","-i","second.mp4","-filter_complex","[0:v]scale=480:640,setsar=1[l];[1:v]scale=480:640,setsar=1[r];[l][r]hstack","-c:v","libx264","-crf","23","-preset","veryfast myoutput.mp4"
  </code></pre>