mkgif

mkgif.sh

#!/bin/sh

usage() {
  echo "Usage: ${0##*/} [-o output] [-r framerate] [-f ffmpeg-filter] [-s width:height] input" 1>&2
  echo ""
  echo "Examples:"
  echo "  ${0##*/} foo.mp4             : Output GIF to foo.gif"
  echo "  ${0##*/} -o bar.gif foo.mp4  : Output GIF to bar.gif"
  echo "  ${0##*/} -r 10 foo.mp4       : Set framerate as 10"
  echo "  ${0##*/} -s 320:-1 foo.mp4   : Resize width to 320px with fixed aspect-ratio"
  echo "  ${0##*/} -f trim=0:1 foo.mp4 : Trim frames from 0 sec to 1 sec"
  exit 1
}

FRAMERATE=""
FILTER=""
SCALE="iw:ih"

while getopts o:r:f:s: OPT
do
  case $OPT in
    "o" ) OUTPUT=$OPTARG;;
    "r" ) FRAMERATE=$OPTARG;;
    "f" ) FILTER=$OPTARG;;
    "s" ) SCALE=$OPTARG;;
    "h" ) usage;;
  esac
done

shift $((OPTIND - 1))
test "$FRAMERATE" != "" && _FILTER="fps=$FRAMERATE,$FILTER" && FILTER="${_FILTER%,}"
test "$SCALE" != "" && _FILTER="$FILTER,scale=$SCALE:flags=lanczos" && FILTER="${_FILTER#,}"
test "$OUTPUT" = "" && OUTPUT="${1%.*}.gif"
test "${OUTPUT%.*}" = "" && usage

TMPOUT="$(mktemp -u).gif"
TMPPALETTE="$(mktemp -u).png"
PALETTE_FILTER="${FILTER},palettegen"

test "$FILTER" = "" && LAVFI_INPUT="[0]" || LAVFI_INPUT="$FILTER [x]; [x]"

ffmpeg -i "$1" -vf "${PALETTE_FILTER#,}" $TMPPALETTE
ffmpeg -i "$1" -i $TMPPALETTE -lavfi "$LAVFI_INPUT[1:v] paletteuse" -y $TMPOUT

if which gifsicle > /dev/null; then
  gifsicle -O2 $TMPOUT > $OUTPUT
  rm $TMPOUT
else
  mv "$TMPOUT" "$OUTPUT"
fi

rm $TMPPALETTE