Bash script to convert video to GIF.

video2gif.sh

#!/bin/bash

set -e

ensure_installed() {
        command -v $1 >/dev/null 2>&1 || { echo -e >&2 "$1 not found.\nTry: sudo apt-get install $1.\nAborting."; exit 1; }
}

function usage() {
	cat << EOF 
$1
Usage: $0 [OPTIONS...] <filename>
Convert a video to GIF.

Example: $0 -r24 -w320 -f3 video.mp4

 GIF format:

  -r <fps>,           set framerate
  -w <width>,         set width in pixel

 Color optimizations:

  -d <size>,          enable color dithering with <size> pattern
  -f <percent>        enable color fuzzing	

 Output selection:

  -o <filename>,      output to <filename>

 Other options:
  -i,                 open folder after image extraction and before conversion 
EOF
	exit 1
}

function cleanup(){
	echo "Cleaning up, please wait."
	rm -rf $TMPDIR
}

while getopts "h?w:r:f:d:o:i" opt; do
	case "$opt" in
	h|\?)
		usage
		;;
	f)	
		CONVERT_OPT="${CONVERT_OPT} -fuzz ${OPTARG}%"
		;;
	w)	
		FFMPEG_OPT="${FFMPEG_OPT} -vf scale=${OPTARG}:-1"
		;;
	r)	
		FFMPEG_OPT="${FFMPEG_OPT} -r ${OPTARG}"
		CONVERT_OPT="${CONVERT_OPT} -delay 1/${OPTARG}"
		;;
	o)	
		OUTPUT=$OPTARG
		;;
	d)	
		CONVERT_OPT="${CONVERT_OPT} -ordered-dither o${OPTARG}x${OPTARG},8,8,4"				
		;;
	i)	
		INSPECT=1
		;;

	*)	
		usage "unknow argument -$opt"
		;;
	esac
done

if command -v avconv >/dev/null 2>&1; then 
	FFMPEG=avconv
elif command -v ffmpeg >/dev/null 2>&1; then
	FFMPEG=ffmpeg
else 
	echo -e >&2 "error: avconv or ffmpeg is required but is not installed. Aborting."
	exit 2;
fi

ensure_installed convert

shift $((OPTIND-1))

FILENAME=$1

if [[ -z "$FILENAME" ]]; then
	usage "error: missing input argument"
fi

if [[ -z "$OUTPUT" ]]; then
	OUTPUT=${FILENAME%.*}.gif
fi

trap cleanup 0

TMPDIR=`mktemp -d`
$FFMPEG -i $FILENAME $FFMPEG_OPT -f image2 $TMPDIR/%04d.png
test -n "$INSPECT" && echo -n "Opening $TMPDIR : " && xdg-open $TMPDIR && read -p "press any key to continue..."
convert $CONVERT_OPT `ls $TMPDIR/*.png` -coalesce -layers RemoveDups -layers Optimize +map $OUTPUT