  if [[ $# -eq 0 ]] ; then
      echo 'missing argument: subtitle_filepath'
      exit $FAIL
  fi
  
  subtitle_filepath="$1"  # contains timing as a subtitles file
  timing_filepath="${subtitle_filepath/.ass/.tsv}"  # timing, as: mot  start_time end_time

  awk -f <(cat - <<-'EOD'
    BEGIN{FS=","} 