gifinate

# default output resolution
WIDTH_SCALE=480

set -x
set -e

BIN_NAME=$0
function usage {
    cat <<EOS
Usage:
    $BIN_NAME <video file> <optional width px>
Example:
    $BIN_NAME foo.mov 200

    # uses default width scale: ${WIDTH_SCALE}
    $BIN_NAME foo.mov
EOS
}

INPUT_FILE=$1
if [ -z "${INPUT_FILE}" ]
then
    usage
    exit 1
fi

if [ ! -z "$2" ]
then
WIDTH_SCALE=$2
fi

palette="/tmp/palette.png"
filters="fps=15,scale=${WIDTH_SCALE}:-1:flags=lanczos"

OUTPUT_FILE="${INPUT_FILE}.gif"
ffmpeg -i "${INPUT_FILE}" -vf "$filters,palettegen" -y $palette
ffmpeg -i "${INPUT_FILE}" -i $palette -filter_complex "
[0:v]
${filters},
paletteuse,
reverse,
tpad='start_duration=1.6',
drawtext='enable=between(t\,0\,1.0):font=serif:fontcolor=white:fontsize=100:x=(w-text_w)/2:y=(h-text_h)/2:text=Fin.',
reverse
" -y "${OUTPUT_FILE}"

gifsicle -O3 --batch "${OUTPUT_FILE}"