gif.sh

#!/bin/sh

start="${1}"
duration="${2}"
input="${3}"
output="${4}"

palette="$(pwd)/palette-tmp.png"
filters="fps=15,scale=800:-1:flags=lanczos"

palette_cmd="ffmpeg -v warning -ss \"${start}\" -t \"${duration}\" -i \"${input}\" -vf \"${filters},palettegen=stats_mode=diff\" -y \"${palette}\""

echo
echo 'Generating palette...'
echo "${palette_cmd}"
eval "${palette_cmd}"
echo

gif_cmd="ffmpeg -v warning -ss \"${start}\" -t \"${duration}\" -i \"${input}\" -i \"${palette}\" -lavfi \"${filters} [x]; [x][1:v] paletteuse=dither=floyd_steinberg\" -y \"${output}\""

echo 'Generating GIF...'
echo "${gif_cmd}"
eval "${gif_cmd}"

rm "${palette}"