title: Fix faulty MP4 metadata
body: <p>I have a problem with incomplete videos. For instance a video whose upload failed. If you check its metadata with <code>ffmpeg -i &lt;filename&gt;</code> you will get a duration like 1 hour but actually only 10mb have been uploaded to the server and the real duration is somewere at 7 minutes. An ugly way to find these videos would be to convert every video and compare the duration output of the converted video with the duration of the original video. Since this approach is way too CPU costly I would like to simply recalculate the duration with FFmpeg. </p>
  
  <p>Is there any command or a good software for that?</p>