gifify

#!/bin/bash

# SPDX-FileCopyrightText: 2015 - 2024 sudorook <daemon@nullcodon.com>
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.

set -Eeuo pipefail

ROOT="$(dirname "${0}")"

source "${ROOT}"/globals

! check_command bc ffmpeg ffprobe sed && exit 3

#
# Define functions
#

function print_usage() {
  show_header "Usage:"
  cat << EOF
  -i  --input          input video (e.g. input.mp4)
  -o  --output         output GIF (e.g. output.gif)
  -s  --start          starting timestamp (e.g. 01:20.5)
  -l  --length         length in seconds (e.g. 3.5)
  -d  --dimensions     output dimensions, comma-delimited (e.g. 1280x720)
  -p  --fps            GIF output FPS (e.g. 30)
  -t  --subtitle       embed subtitles? (yes, no, both)
EOF
}

function scan_input {
  local vstring
  local sstring

  fstring="$(ffprobe -v error -show_format file:"${IN}")"
  vstring="$(ffprobe -v error \
               -select_streams v:0 -show_streams file:"${IN}")"
  sstring="$(ffprobe -v error \
               -select_streams s -show_streams -of flat file:"${IN}")"

  DURATION="$(echo "${fstring}" | sed -n "s/^duration=\(.*\)$/\1/p")"
  VCODEC="$(echo "${vstring}" | sed -n "s/^codec_name=\(.*\)$/\1/p")"
  WIDTH="$(echo "${vstring}" | sed -n "s/^width=\(.*\)$/\1/p")"
  HEIGHT="$(echo "${vstring}" | sed -n "s/^height=\(.*\)$/\1/p")"
  if ! [[ -v DIMENSIONS ]]; then
    DIMENSIONS=("${WIDTH}x${HEIGHT}")
  fi
  ASPECTRATIO="$(echo "${vstring}" | sed -n "s/^display_aspect_ratio=\(.*\)$/\1/p")"
  SIDX="$(echo "${sstring}" | sed -n "s/^streams\.stream.\([0-9]\+\)\.disposition.default=1$/\1/p")"
  SIDX="${SIDX:-0}"
  SCODEC="$(echo "${sstring}" | sed -n "s/^streams.stream.${SIDX}.codec_name=\"\(.*\)\"$/\1/p")"
}

function make_image_subs {
  local in="${IN}"
  local dim="${3}"
  local width
  local height
  local out
  local cmd

  # compute the width and height for the image
  if [[ "${dim}" = native ]]; then
    width="${WIDTH}"
    height="${HEIGHT}"
    scale=
  else
    width="$(echo "${dim}" | sed -n "s,^\([0-9]*\)[:x]\([0-9]*\)$,\1,p")"
    height="$(echo "${dim}" | sed -n "s,^\([0-9]*\)[:x]\([0-9]*\)$,\2,p")"
    if [ -z "${width}" ] && [ -n "${height}" ]; then
      scale=",scale=-1:${height}:flags=lanczos"
      width="$(printf %.0f "$(echo "${height} * ${ASPECTRATIO}" | sed 's,:,/,g' | bc -l)")"
    elif [ -n "${width}" ] && [ -z "${height}" ]; then
      scale=",scale=${width}:-1:flags=lanczos"
      height="$(printf %.0f "$(echo "${width} / (${ASPECTRATIO})" | sed 's,:,/,g' | bc -l)")"
    elif [ -n "${width}" ] && [ -n "${height}" ]; then
      scale=",scale=${width}:${height}:flags=lanczos"
    else
      width="${WIDTH}"
      height="${HEIGHT}"
      scale=
    fi
  fi

  # add dimensions to the output file name
  out="${OUT%.*}-${width}x${height}-sub.${FORMAT}"

  # generate the command
  cmd="ffmpeg -v warning -y -i file:${in@Q} -ss ${START}"

  # -t and -to are mutually exclusive, so set duration over end stamp
  # (mirrors ffmpeg default behavior)
  if [[ -v LENGTH ]]; then
    cmd="${cmd} -t ${LENGTH}"
  elif [[ -v END ]]; then
    cmd="${cmd} -to ${END}"
  fi

  # burn the subtitles into a short video
  case "${SCODEC}" in
    mov_text | subrip)
      cmd="${cmd} -map 0:v:0 -c:v:0 ${VCODEC} -an -sn -vf 'subtitles=${in@Q}:si=${SIDX}' -f ${VCODEC} ${TMP}"
      ;;
    hdmv_pgs_subtitle | dvd_subtitle)
      cmd="${cmd} -an -filter_complex '[0:v:0][0:s:${SIDX}] overlay [v]' -map '[v]' -f ${VCODEC} ${TMP}"
      ;;
    *)
      show_warning "WARNING: No subtitle streams found in ${IN}. Skipping."
      return
      ;;
  esac
  echo "${cmd}" >&2
  eval "${cmd}"

  # convert the short video into an image
  case "${FORMAT}" in
    gif)
      cmd="ffmpeg -v warning -y -i file:${TMP} -filter_complex '[0:v] ${FPS:+fps=${FPS}${scale},}split [a][b];[a] palettegen [p];[b] fifo [c];[c][p] paletteuse' -loop 0 -f gif file:${out@Q}"
      ;;
    webp)
      cmd="ffmpeg -v warning -y -i file:${TMP} ${FPS:+-vf \'fps=${FPS}${scale}\' }-vcodec libwebp -lossless 0 -compression_level 0 -q:v 100 -loop 0 -preset picture -fps_mode passthrough -f webp file:${out@Q}"
      ;;
  esac
  echo "${cmd}" >&2
  eval "${cmd}"
}

function make_image {
  local in="${IN}"
  local dim="${3}"
  local width
  local height
  local out
  local cmd

  # compute the width and height for the image
  if [[ "${dim}" = native ]]; then
    width="${WIDTH}"
    height="${HEIGHT}"
    scale=
  else
    width="$(echo "${dim}" | sed -n "s,^\([0-9]*\)[:x]\([0-9]*\)$,\1,p")"
    height="$(echo "${dim}" | sed -n "s,^\([0-9]*\)[:x]\([0-9]*\)$,\2,p")"
    if [ -z "${width}" ] && [ -n "${height}" ]; then
      scale=",scale=-1:${height}"
      width="$(printf %.0f "$(echo "${height} * ${ASPECTRATIO}" | sed 's,:,/,g' | bc -l)")"
    elif [ -n "${width}" ] && [ -z "${height}" ]; then
      scale=",scale=${width}:-1"
      height="$(printf %.0f "$(echo "${width} / (${ASPECTRATIO})" | sed 's,:,/,g' | bc -l)")"
    elif [ -n "${width}" ] && [ -n "${height}" ]; then
      scale=",scale=${width}:${height}"
    else
      width="${WIDTH}"
      height="${HEIGHT}"
      scale=
    fi
  fi

  # add dimensions to the output file name
  out="${OUT%.*}-${width}x${height}.${FORMAT}"

  # generate the command
  cmd="ffmpeg -v warning -y -ss ${START}"

  # -t and -to are mutually exclusive, so set duration over end stamp (mirrors
  # ffmpeg default behavior)
  if [[ -v LENGTH ]]; then
    cmd="${cmd} -t ${LENGTH}"
  elif [[ -v END ]]; then
    cmd="${cmd} -to ${END}"
  fi
  cmd="${cmd} -i file:${in@Q} -an -sn"

  # generate separate filter strings for GIF and WebP formats
  case "${FORMAT}" in
    gif)
      cmd="${cmd} -filter_complex '[0:v:0] ${FPS:+fps=${FPS}${scale},}split [a][b];[a] palettegen [p];[b] fifo [c];[c][p] paletteuse' -loop 0 -f gif file:${out@Q}"
      ;;
    webp)
      cmd="${cmd} -map 0:v:0 ${FPS:+-vf \'fps=${FPS}${scale}\' }-vcodec libwebp -lossless 0 -compression_level 0 -q:v 100 -loop 0 -preset picture -fps_mode passthrough -f webp file:${out@Q}"
      ;;
  esac
  echo "${cmd}" >&2
  eval "${cmd}"
}

#
# Set globals
#

EMBED_SUBS=false
START=0.0

TMP=$(mktemp)
trap 'rm -f ${TMP}; exit' INT TERM ERR EXIT

#
# Parse input
#

OPTIONS=hi:o:s:e:l:d:t:p:
LONGOPTIONS=help,input:,output:,start:,end:,length:,resolution:,subtitle:,fps:
PARSED=$(getopt -o "${OPTIONS}" --long "${LONGOPTIONS}" -n "${0}" -- "${@}")
eval set -- "${PARSED}"

while [ ${#} -ge 1 ]; do
  case "${1}" in
    -i | --input)
      IN="${2}"
      scan_input
      shift 2
      ;;
    -o | --output)
      OUT="${2}"
      case "${2##*.}" in
        GIF | gif | Gif)
          FORMAT=gif
          ;;
        WEBP | webp | WebP)
          FORMAT=webp
          ;;
        *)
          show_error "ERROR: ${2@Q} unsupported output format."
          exit 3
          ;;
      esac
      shift 2
      ;;
    -s | --start)
      START="${2}"
      shift 2
      ;;
    -e | --end)
      END="${2}"
      shift 2
      ;;
    -l | --length)
      LENGTH="${2}"
      shift 2
      ;;
    -t | --subtitle)
      EMBED_SUBS="${2}"
      shift 2
      ;;
    -d | --dimensions)
      IFS=',' read -r -a DIMENSIONS <<< "${2}"
      shift 2
      ;;
    -p | --fps)
      FPS="${2}"
      shift 2
      ;;
    -h | --help)
      print_usage
      exit
      ;;
    --)
      shift
      break
      ;;
    *)
      show_error "Error"
      exit 3
      ;;
  esac
done

#
# Main
#

# Check if variables are set before running ffmpeg.
if ! [[ -v IN ]] || ! [[ -v OUT ]]; then
  show_error "Try again. Usage:"
  print_usage
  exit 3
fi

# If duration is unset, go to the end of the video...
if ! [[ -v LENGTH ]] && ! [[ -v END ]]; then
  LENGTH="$(echo "${DURATION} - ${START}" | bc -l)"
fi

# Create a GIF/WebP for all dimensions listed in the input.
for dim in "${DIMENSIONS[@]}"; do
  case "${EMBED_SUBS}" in
    yes | true | y)
      make_image_subs "${IN}" "${OUT}" "${dim}"
      ;;
    no | false | n)
      make_image "${IN}" "${OUT}" "${dim}"
      ;;
    both)
      make_image "${IN}" "${OUT}" "${dim}"
      make_image_subs "${IN}" "${OUT}" "${dim}"
      ;;
    *)
      show_error "Try again. Usage:"
      print_usage
      exit 3
      ;;
  esac
done