title: js MediaRecorder + ffmpeg
body: <p>Help me, please. I record a video with javascript using MediaRecorder and then I store it on my server.</p>
  <p>The VLC player plays the video well, but a browser has difficult to play it. A video recorded on IOS loads up to 2 minutes before the browser starts playing it(looks like the browser loads the video completely before playing it). A video from android doesn't contain the timeline, but starts much faster.</p>
  <p>The video from android I fixed by fast re-encoding <code>ffmpeg -i without_timeline.webm -c copy fixed.webm</code> it works well.</p>
  <p>I tried to fix the video from IOS with the similar command <code>ffmpeg -i long_started.mp4 -c copy fixed.mp4</code>, but the result is worse.</p>
  <p>There are a lot of errors</p>
  <p><strong>Non-monotonous DTS in output stream 0:0;</strong></p>
  <p><strong>Non-monotonous DTS in output stream 0:1;</strong></p>
  <p>The new video is rotated, has freezes, repeats and wrong time.</p>
  <p>I've spent a week, but without success.</p>