Create a m4b file from mp3 files with metadata and image cover (tailored for audioteka.cz)

make-audiobook.sh

#!/bin/bash -x

CATEGORY="audioteka"

function get_mp3_tag() {
	local file="$1"
	local tag="$2"

	ffprobe -v error -show_entries format_tags="$tag" -of default=noprint_wrappers=1:nokey=1 "$file"
}

function create_metadata() {
	local dir="$1"
	local meta_file="$2"
	local list_file="$3"
	local playlist="$dir/playlist.pls"

	echo "" >"$list_file"
	echo ";FFMETADATA1" >"$meta_file"
	local metadata=0
	local start=0
	local title
	local title
	local length
	local album
	local artist

	while IFS= read -r line; do
		if [[ $line == File* ]]; then
			filename="$FOLDER_PATH/$(echo "$line" | cut -d '=' -f 2)"
			if [ $metadata -eq 0 ]; then
				metadata=1
				album=$(get_mp3_tag "$filename" album)
				artist=$(get_mp3_tag "$filename" artist)

				{
					echo "title=$album"
					echo "album=$album"
					echo "artist=$artist"
					echo "album_artist=$artist"
					echo "genre=$(get_mp3_tag "$filename" genre)"
					echo "date=$(get_mp3_tag "$filename" date)"
					echo "comment=$(get_mp3_tag "$filename" comment)"
					echo "category=$CATEGORY"
				} >>"$meta_file"
			fi
		elif [[ $line == Title* ]]; then
			title=$(echo "$line" | cut -d '=' -f 2)
		elif [[ $line == Length* ]]; then
			length=$(echo "$line" | cut -d '=' -f 2)
			echo "file '$filename'" >>"$list_file"

			{
				echo "[CHAPTER]"
				echo "TIMEBASE=1/1000"
				echo "START=$start"
				start=$((start + length))
				echo "END=$start"
				echo "title=$title"
			} >>"$meta_file"
		fi
	done <"$playlist"
}

# Check if the correct number of arguments is provided
if [ "$#" -ne 1 ]; then
	echo "Usage: $0 <path_to_folder>"
	exit 1
fi

FOLDER_PATH=""
if [[ -f "$1" && $(file -b --mime-type "$1") == application/zip ]]; then
	FOLDER_PATH=$(basename "$1" .zip)
	mkdir -p "$FOLDER_PATH"
	unzip -q "$1" -d "$FOLDER_PATH"
elif [ -d "$1" ]; then
	FOLDER_PATH="$1"
else
	echo "Don't know what to do with $1"
	exit 1
fi

BOOK_NAME=$(basename "$FOLDER_PATH")

# Check if the provided path is a directory
if [ ! -d "$FOLDER_PATH" ]; then
	echo "Error: $FOLDER_PATH is not a directory"
	exit 1
fi

# Check if the cover image exists in the directory
COVER_FILE="$FOLDER_PATH/$BOOK_NAME-duze.jpg"
if [ ! -f "$COVER_FILE" ]; then
	echo "Error: Cover image '$COVER_FILE' not found in the directory"
	exit 1
fi

# Output files
LIST_FILE="$BOOK_NAME.files.txt"
META_FILE="$BOOK_NAME.meta"
COMBINED_FILE="$BOOK_NAME.mp3"
CONVERTED_FILE="$BOOK_NAME.converted.m4b"
OUTPUT_FILE="$BOOK_NAME.m4b"

create_metadata "$FOLDER_PATH" "$META_FILE" "$LIST_FILE"

# Combine MP3 files into one MP3 file
[ -f "$COMBINED_FILE" ] || ffmpeg -f concat -safe 0 -i "$LIST_FILE" -c copy "$COMBINED_FILE"
# Convert into mp4b
[ -f "$OUTPUT_FILE" ] || ffmpeg -i "$COMBINED_FILE" "$CONVERTED_FILE"
# Add metadata to the m4b file
[ -f "$OUTPUT_FILE" ] || ffmpeg -i "$CONVERTED_FILE" \
	-i "$META_FILE" \
	-i "$COVER_FILE" \
	-map 0:a -map_metadata 1 -map 2:v -disposition:v:0 attached_pic -c copy -movflags +faststart \
	"$OUTPUT_FILE"

echo "M4B file created successfully: $OUTPUT_FILE"

Hi I put some time and effort to make this work on my computer so this is my pay back to this useful script

1. You need to have a cover for your book name like folder-name-duez.jpg
2. You need to have list of all files in file named playlist.pls. The easiest way to create that list is to use clementine player on linux
3. Enjoy it.

Thanks for your effort developing this