convert2alac.sh

convert2alac.sh

#!/usr/bin/env bash
set -ueo pipefail

get_cover_index() {
	input_file="${1}"
	ffprobe -i "${input_file}" \
		-loglevel -8 \
		-show_streams \
		-of json | jq '.streams[] | select(.disposition.attached_pic==1) | .index'
}

get_cover_file() {
	input_dir="${1}"

	fd -1 '^(?:[cC][oO][vV][eE][rR]|[fF][lL][oO][dD][eE][rR])\d*\.(?:[jJ][pP][eE]?|[pP][nN])[gG]$' "${input_dir}"
}

convert() {
	input_file="$1"
	out_dir="$2"

	echo "[INFO] Input: ${input_file}"
	input_file_dir=$(dirname "${input_file}")
	input_file_name=$(basename "${input_file}")
	command="ffmpeg -loglevel error -hide_banner -y -i \"${input_file}\" "
	cover_idx=$(get_cover_index "${input_file}")
	cover_file=$(get_cover_file "${input_file_dir}")
	if [[ -n ${cover_idx} ]]; then
		echo "[INFO] Cover from input file[idx:${cover_idx}]"
		command+=" -map 0:${cover_idx} -c:v copy "
	elif [[ -f "${cover_file}" ]]; then
		echo "[INFO] Cover from image file: ${cover_file}"
		command+=" -i \"${cover_file}\" -map 1 -c:v copy"
	else
		echo "[WARN] Cover not found"
	fi
	command+=" -disposition:v:0 attached_pic "
	command+=" -map 0:a -map_metadata 0 -c:a alac "
	command+=" \"${out_dir}/${input_file_dir}/${input_file_name%.*}.m4a\" "
	if [[ ${DRY_RUN:-} == "1" ]]; then
		echo "$command"
	else
		echo "[INFO] Result: ${out_dir}/${input_file_dir}/${input_file_name%.*}.m4a"
		mkdir -p "${out_dir}/${input_file_dir}"
		eval "$command"
	fi
}

help() {
	printf "%s: -h\n\tShow help.\n" "$0"
	printf "%s: -o\n\tOutput dir.\n" "$0"
	printf "%s: -i\n\tInput dir.\n" "$0"
	printf "%s: -d\n\Dry run.\n" "$0"
}

main() {
	while getopts "hdi:o:" OPT; do
		case ${OPT} in
		h) help && exit 0 ;;
		i) input="${OPTARG}" ;;
		d) export DRY_RUN=1 ;;
		o) output="${OPTARG}" ;;
		?) help && exit 1 ;;
		esac
	done

	if [[ ! -d "${output:-}" ]]; then
		echo "[Error] Output dir not spec or not exist." 1>&2 && exit 1
	fi

	if [[ -f "${input:-}" ]]; then
		convert "${input}" ${output}
	elif [[ -d "${input:-}" ]]; then
		bash -c "cd \"${input}\"; fd -e flac -x $0 -i \"{}\" -o \"${output}\""
	else
		echo "[Error] Input not spec or not exist." 1>&2 && exit 1
	fi

	unset DRY_RUN
}

main "$@"