Generate optimized GIFs with FFmpeg

gif.sh

#!/bin/bash

# GIF parameters
fps=24
width=960

if [ "$1" = "" ]; then
  printf "\e[31mSpecify input files\e[m\n"
  exit 1
fi

printf "GIF parameters:\n"
printf " - FPS: $fps\n"
printf " - Width: $width\n"
printf "\n"

readonly TMP_DIR=$(mktemp -d)

printf "Created temporary directory: $TMP_DIR\n"
printf "\n"

function cleanup {
  rm -r $TMP_DIR && \
  printf "Deleted temporary directory: $TMP_DIR\n"
}

trap cleanup EXIT

function generate {
  local readonly PALETTE_FILE=$TMP_DIR/$(basename "$1").palette.png
  local readonly OUTPUT_FILE=$1.gif

  printf "Input $2/$3: $1\n" && \
  printf "Generating palette...\n" && \
  ffmpeg -v warning -y -i "$1" -vf "palettegen" "$PALETTE_FILE" && \
  printf "Generated palette: $PALETTE_FILE\n" && \
  printf "Generating GIF...\n" && \
  ffmpeg -v warning -y -i "$1" -i "$PALETTE_FILE" -lavfi "fps=$fps,scale=$width:-1:flags=lanczos [x]; [x][1:v] paletteuse=dither=bayer:bayer_scale=5:diff_mode=rectangle" "$OUTPUT_FILE" && \
  printf "\e[32mGenerated GIF: $OUTPUT_FILE\e[m\n"

  printf "\n"
}

index=1
for i in "$@"; do
  generate "$i" $index $#
  let index++
done

Usage

gif.sh file ...

References

• ffmpeg Documentation
• Optimizing GIFS with FFMPEG · Cassidy K
• ffmpegで動画を綺麗なgifに変換するコツ - 丁寧に手を抜く