title: Concat multiple video and audio files with ffmpeg
body: <p>I have an array of audio and video clips, where each audio clip has a 1:1 correlation with it's video clip.  The encoding of each video and each audio clip are the same.  How can I concat all of the audio clips, and all the video clips, then merge them together to output a video.  As of now I only figured out how to merge 1 audio clip with 1 video clip:</p>
  
  <pre><code>$ ffmpeg -i video_1.webm -i audio_1.wav -acodec copy -vcodec copy output.mkv
  </code></pre>
  
  <p><strong>Update</strong>
  I just came across <code>mkvmerge</code> would this possibly be a better option?</p>