embed_itunes_metadata.sh

#!/bin/bash
set -euo pipefail

## This is a script made for the purpose of embedding metadata into media files
## from an iTunes library, allowing the media files to be used in any player.
##
## Given a media file extracted from iTunes, search the current directory for
## iTunes plist files, and if a matching file is found metadata is extracted
## from the plist file and embedded into the media file. The media file is then
## written into the directory 'out'.
##
## Can also set the environment variable COVERART to point to a file containing
## cover art to embed.

if [[ "$#" -gt 1 ]]; then
	for ARG in "$@"; do
		"$0" "$ARG"
		echo
	done
	exit
fi

rdom () { local IFS=\> ; read -d \< E C ;}

MEDIA="$1"
EXTENSION="${MEDIA##*.}"

echo "Processing file $MEDIA"

ID=$(exiftool -S -'ItemID' -- "$MEDIA" | awk '{print $2}')
ID=$(printf '%d' "$ID")

echo "ID is $ID"

PLIST=""
for FILE in *.plist; do
	PLIST=$(plistutil -i "$FILE")
	# xq doesn't work for parsing this

	if  [[ "$PLIST" == *"$ID"* ]]; then
		echo "Found plist file $FILE"
		break
	fi

done

if [ -z "${PLIST:+x}" ]; then
	echo "Did not find plist file"
	exit 1
fi

# Key is key in plist, value is mp4 metadata tag
declare -A SEARCH_VARS
SEARCH_VARS[artistName]=Artist
SEARCH_VARS[itemName]=Title
SEARCH_VARS[trackNumber]=Tracknumber
SEARCH_VARS[playlistName]=Album
SEARCH_VARS[year]=Year

NEXT=""
declare -A VARS
while rdom; do
	# Ignore terminators
	if [[ "${E:0:1}" == "/" ]]; then
		continue
	fi

	# Ignore empty values
	if [ -z "${C:+x}" ]; then
		continue
	fi

	if [[ "$E" == "key" ]]; then
		NEXT="$C"
	else
		KEY="$NEXT"
		NEXT=""

		FOUND=0
		for S in "${!SEARCH_VARS[@]}"; do
			if [[ "$S" == "$KEY" ]]; then
				FOUND=1
				break
			fi
		done
		if [ "$FOUND" -eq 0 ]; then
			continue
		fi

		VARS["$KEY"]="$C"


	fi

done <<< "$PLIST"

cp -- "$MEDIA" tmp

EXIF_ARGS=(-overwrite_original_in_place)
for KEY in "${!VARS[@]}"; do
	echo "$KEY = ${VARS[$KEY]}"
	VALUE="${VARS[$KEY]}"
	TAG="${SEARCH_VARS["$KEY"]}"
	EXIF_ARGS+=(-"$TAG"="$VALUE")
done

exiftool "${EXIF_ARGS[@]}" ./tmp

if [ -n "${COVERART+x}" ]; then
	AtomicParsley ./tmp --artwork "$COVERART" --output atomictmp
	mv atomictmp tmp
fi

OUTDIR="${VARS[playlistName]}"
mkdir -p "$OUTDIR"
OUT="$OUTDIR/${VARS[trackNumber]} - ${VARS[itemName]}.$EXTENSION"

mv tmp "$OUT"

echo "Wrote $OUT"