makegif.sh

#!/bin/sh

# From http://blog.pkh.me/p/21-high-quality-gif-with-ffmpeg.html

# Usage:
#   ./makegif.sh inputframes output.gif
# where inputframes is a directory containing .png frames

# Change size here
filters="scale=640:-1:flags=lanczos"

# Generate palette, you can change max_colors
palette="palette.png"
ffmpeg -thread_queue_size 512 -v warning -pattern_type glob -i "$1/*.png" -vf "$filters,palettegen=stats_mode=diff:max_colors=256:reserve_transparent=false" -y $palette

# Create gif
ffmpeg -thread_queue_size 512 -v warning -pattern_type glob -i "$1/*.png" -i $palette -lavfi "$filters [x]; [x][1:v] paletteuse=dither=sierra2_4a" -y $2

# Optimise and adjust
# * Delay between frames is 100ths of a second, for example 4 is 25fps
# * To repeat twice do "#0-" "#0-"
gifsicle --batch --optimize=03 --delay=4 $2 "#0-"

# Display final file size
stat --format=%s $2