#!/bin/sh

filename=$1

if [ -z "$filename" ]; then
  echo "You must provide a file for the script."
  echo "Example:"
  echo "     `basename $0` foo.mp4"
  exit 1
fi

if [ ! -f "$filename" ]; then
  echo "The file provided does not exist."
  exit 1
fi

friendly_filename=`sed -E 's/[^[:alnum:][:space:]]+/_/g' <<< "$filename"`
out_dirname="frames-$friendly_filename"

#debug
if false; then
  echo "filename:"
  echo "    $filename"

  echo "out_dirname:"
  echo "    $out_dirname"

  echo "friendly_filename:"
  echo "    $friendly_filename"

  exit 0
fi

mkdir -p $out_dirname
ffmpeg -i $filename -c:v png $out_dirname/frame%04d.png

if [ $? -ne 0 ]; then
  echo ""
  echo ""
  echo ""
  echo "The ffmpeg command did not return an exit status of 0."
  echo "Exiting script..."

  rm -r $out_dirname
  exit 1
fi