title: Fastest way to add -movflags +faststart to an MP4 using FFMPEG, leaving everything else as-is
body: <p>I want to add <code>-movflags +faststart</code> to an mp4 file. Basically that is all I want to do, nothing else should be changed. I am using ffmpeg.</p>
  <p>What's the fastest way to do this? Do I have to re-encode the whole video? Or is there a better/easier way?</p>