FLAC 2 ALAC

flac2alac.sh

#!/bin/bash

# get cover art using sacad. try only once.
function get_cover_art() {
    local artist="$1"
    local album="$2"
    local dstdir="$3"
    
    local albumdir="${dstdir}/${artist}/${album}"
    local artfile="${albumdir}/${artist} - ${album}.png"
    local tryfile="${albumdir}/.no-art"

    mkdir -p "$albumdir"
    if [[ ! -f "$artfile" && ! -f "$tryfile" ]]; then
        echo "Downloading art for album: $album"
        sacad "$artist" "$album" 600 "$artfile" 2> /dev/null
        touch "$tryfile"
    fi
}

# check if an existing file has cover art using ffprobe
function has_cover_art() {
    local file=$1
    local cover_art=$(ffprobe -v error -select_streams v -show_entries stream=codec_name -of default=nw=1:nk=1 "$file")
    
    if [[ $cover_art == 'mjpeg' ]] || [[ $cover_art == 'png' ]]; then
        return 0
    else
        return 1
    fi    
}

# convert from flac to alac (m4a). Place in album dir. albumart argument is optional.
function flac_alac() {
    local flacfile="$1"
    local albumdir="$2"
    local albumart="$3"
    
    if has_cover_art "$flacfile"; then # keep existing album art
        ffmpeg -y \
            -i "$flacfile" \
            -map 0:a -map 0:v \
            -c:v copy -c:a alac -disposition:v:0 attached_pic \
            "${albumdir}/$(basename "${flacfile%.flac}.m4a")"
    elif [[ $albumart ]]; then
        ffmpeg -y \
            -i "$flacfile" \
            -i "$albumart" \
            -map 0:a:0 -map 1 \
            -c:v copy -c:a alac -disposition:v:0 attached_pic \
            "${albumdir}/$(basename "${flacfile%.flac}.m4a")"
    else # just the audio
        ffmpeg -y \
            -i "$flacfile" \
            -map 0:a:0 \
            "${albumdir}/$(basename "${flacfile%.flac}.m4a")"
    fi
}

# globals

# expected srcdir format is srcdir/artist/album/file
srcdir="$1"

ext="flac"
dstdir="$HOME/Music"

mkdir -p $dstdir
for file in ${srcdir}/**/*.${ext}; do
    # validate the file name
    if [[ $file =~ .*[[:space:]]-[[:space:]].*[[:space:]]-[[:space:]].*[[:space:]]-[[:space:]].* ]]; then
        # File format: artist - album - track - song.${ext}
        #                                 (.*/)?(.*) - (.*) - (.*) - (.*)\.${ext}
        artist="$(echo $file | sed -E 's|(.*/)?(.*) - (.*) - (.*) - (.*)\.'${ext}'|\2|')"
        album="$( echo $file | sed -E 's|(.*/)?(.*) - (.*) - (.*) - (.*)\.'${ext}'|\3|')"
        track="$( echo $file | sed -E 's|(.*/)?(.*) - (.*) - (.*) - (.*)\.'${ext}'|\4|')"
        song="$(  echo $file | sed -E 's|(.*/)?(.*) - (.*) - (.*) - (.*)\.'${ext}'|\5|')"
        
        # create a directory if needed
        mkdir -p "${dstdir}/${artist}/${album}"
        
        # fetch album art if missing
        get_cover_art "$artist" "$album" "$dstdir"
        
        # convert file
        echo "$file"
        echo "${dstdir}/${artist}/${album}"
        echo "${dstdir}/${artist}/${album}/${artist} - ${album}.png"
        if [[ -f "${dstdir}/${artist}/${album}/${artist} - ${album}.png" ]]; then
            flac_alac \
                "$file" \
                "${dstdir}/${artist}/${album}" \
                "${dstdir}/${artist}/${album}/${artist} - ${album}.png"
        else
            flac_alac \
                "$file" \
                "${dstdir}/${artist}/${album}"
        fi
     fi
done