# Convert WEBM (screen record) to seekable WEBM (quality might reduce)
ffmpeg -i screencast.webm \\
  -c:v libvpx \\
  -g 120 \\
  -keyint_min 120 \\
  -auto-alt-ref 0 \\
  -c:a copy \\
  fixed.webm
  
  # Convert WEBM to MP4
  ffmpeg -i screencast.webm  -c:v libx264 -crf 20 -c:a aac -strict experimental out.mp4