#!/bin/bash

INPUT=$1
START=$2
STOP=$3

if [[ -n $START ]]; then
  START="-ss $START"
fi

if [[ -n $STOP ]]; then
  STOP="-t $STOP"
fi

if [[ -z INPUT ]]; then
  echo "usage: $0 <input> [<start> <stop>]"
fi

ffmpeg $START $STOP -i $INPUT -acodec libmp3lame -ab 128k $INPUT.mp3