ffmpeg wrapper script to transcode select portions of original file as h264. WARNING: I have no idea what I'm doing [insert dog meme here]

h264.sh

#!/bin/bash
# Usage: h264 <infile> <HH:MM:SS-HH:MM:SS> [<outfile>]
set -e

infile="$1"
fromto="$2"

if [ -n "$3" ]; then
  outfile="$3"
else
  outfile="${infile%.*}.mov"
fi

seconds() {
  local parts=( ${1//:/ } )
  while [ "${#parts[@]}" -lt 3 ]; do parts=( 0 ${parts[*]} ); done
  echo $(( parts[2] + parts[1] * 60 + parts[0] * 3600 ))
}

from="$(seconds "${fromto%-*}")"
to="$(seconds "${fromto#*-}")"
duration=$(( to - from ))

exec ffmpeg -loglevel warning -ss "$from" -i "$infile" -to "$duration" "$outfile"