title: How do I use a buffer object as Ffmpeg's source input
body: <p>I'm using node.js as a web server (fluent-ffmpeg as the ffmpeg library).</p>
  
  <ol>
  <li><p>I have two videos on amazon s3, when I retrieve them, they come as Buffer objects.</p></li>
  <li><p>I'd like to retrieve them, combine them, and send them to the client, without having to save them as files.</p></li>
  </ol>