title: Combine multiple videos with specific duration
body: <p>I am going to concat multiple videos so I can get one video file with FFmpeg.</p>
  <p>I've found several ways to implement this but all ways I found can't concat with specific duration of each video.</p>
  <p>It means they only concat whole videos.</p>
  <p>Exactly, what I wanted is to insert video1 into video2 with specific time. While searching several articles related with this, I checked many articles say &quot;It is impossible with ffmpeg&quot;.</p>
  <p>So I am trying to split video2 into two videos( like video2-1,video2-2) and concat video1, video2-1, video2-2.</p>