Convert a video to a GIF

gif-from-video.sh

#!/bin/sh

# Because I can never rememeber the magic incantations.
# Note that FFMPEG won't do as good a job as GIF Brewery or other apps, but it's good enough in a pinch.

IN_FILE="$1"
OUT_FILE="${IN_FILE%.*}.gif"
PALETTE_FILE="${IN_FILE%.*}-palette.png"
if [[ "" == "${SEEK_SECS}" ]] ; then
  SEEK_SECS="0"
fi
if [[ "" == "$DURATION" ]] ; then
  DURATION=$(ffprobe -i "${IN_FILE}" -v quiet -show_entries format=duration -hide_banner -of default=noprint_wrappers=1:nokey=1)
fi
if [[ "" == "${FPS}" ]] ; then
  FPS="15"
fi
if [[ "" == "${WIDTH}" ]] ; then
  WIDTH=$(ffprobe -i "${IN_FILE}" -v error -of default=noprint_wrappers=1:nokey=1 -select_streams v:0 -show_entries stream=width)
fi
if [[ -f "${PALETTE_FILE}" ]] ; then
  rm "${PALETTE_FILE}"
fi

ffmpeg -hide_banner -ss "${SEEK_SECS}" -t "${DURATION}" -i "${IN_FILE}" -vf  "fps=${FPS},scale=${WIDTH}:-1:flags=lanczos,palettegen" "${PALETTE_FILE}"
ffmpeg -hide_banner -ss "${SEEK_SECS}" -t "${DURATION}" -i "${IN_FILE}" -i "${PALETTE_FILE}" -filter_complex "fps=${FPS},scale=${WIDTH}:-1:flags=lanczos[x];[x][1:v]paletteuse" "${OUT_FILE}"
rm "${PALETTE_FILE}"