djcev.com

#!/bin/sh
#
#  Copyright (c) 2015-2022, Cameron Vanderzanden. Available under the
#  terms of the 2-clause BSD license. Please see the file "LICENSE" in
#  the root dir of this repository for more information.
#
#- audio_to_cbr320.sh 2015/02/18 cev
#- audio_to_cbr320.sh 2021/07/23 cev
#- audio_to_cbr320.sh 2022/01/29 cev
## Usage: audio_to_cbr320.sh [-3fhV] <inputfile> <outputfile>
## 
##     Convert <inputfile> flac/mp3 into a 320kbps constant-bitrate mp3
##     file at <outputfile>.
## 
##       -3     Operate on mp3 files
##       -f     Operate on flac files
##       -h     Show help
##       -V     Print version info
#
# TODO: This needs better error checking.

[ -x $HOME/.local/bin/cev_print.sh ] && . $HOME/.local/bin/cev_print.sh

self="${0##*'/'}"
mode=""
ext=""

if [ $self = "flac_to_cbr320.sh" -o $self = "flac_to_cbr320" ]; then
    mode="flac"
    ext="flac"
elif [ $self = "mp3_to_cbr320.sh" -o $self = "mp3_to_cbr320" ]; then
    mode="mp3"
    ext="mp3"
fi

die_inputoutputsame() {
    print_self error
    printf "%binput file %b%s %band output file %b%s %bare the same!%b\n" \
        "$_norm" "$_error" "$1" "$_norm" "$_error" "$2" "$_norm" "$_clear" >&2
    exit 1
}

die_invalidargumentcount() {
    print_self error
    printf "%b need an input file and output file! " "$_norm" >&2
    printf "(Argument count != %b2%b).%b\n" "$_error" "$_norm" "$_clear" >&2
    exit 1
}

die_noinput() {
    print_self error
    printf "%binput file %b%s %bdoes not exist!%b\n" \
        "$_norm" "$_error" "$1" "$_norm" "$_clear" >&2
    exit 1
}

die_nooutput() {
    print_self error
    printf "%boutput file not specified!%b\n" "$_norm" "$_clear" >&2
    exit 1
}

die_unknownfiletype() {
    print_unknownfiletype "$*"
    exit 1
}

is_flac() { test_mimetype.sh -t "audio/x-flac" "$@" ; }

is_mp3() {
    if test_mimetype.sh -t "audio/mpeg" "$@"; then
        return 0
    else
        # test file extension
        tmpname="$(basename "$@" ".mp3")"
        tmpname2="${@##$tmpname}"
        if [ "$tmpname2" = ".mp3" ]; then
            return 0
        fi
    fi
    return 1
}

mp3_copytags() {
    # copy tags using py-mutagen
    # TODO: replicate the flac_copytags system below to re-generate the mp3
    # tags, instead of copying (possibly corrupt) tags with mid3cp.
    mid3cp --write-v1 "$1" "$2"
}

mp3_transcode() {
    inpfile="${1}"
    outfile="${2}"
    wavfile="${outfile}.wav"

    # decode; had to update this 2022/01/29 because mpv options changed.
    mpv --msg-level=all=warn \
        --no-audio-display \
        --no-video \
        --audio-samplerate=44100 \
        --ao=pcm \
        --ao-pcm-file="${wavfile}" \
        "$inpfile"
    # encode
    lame --preset insane -S "$wavfile" "$outfile"
    rm -v "$wavfile"
}

# There's a better way to do this.
flac_gettag() {
    metaflac --no-utf8-convert --list "$1" | grep "$2" | cut -d'=' -f 2-
}

flac_copytags() {
    title="$(flac_gettag "$1" "TITLE=")"
    artist="$(flac_gettag "$1" "ARTIST=")"
    album="$(flac_gettag "$1" "ALBUM=")"
    year="$(flac_gettag "$1" "DATE=")"
    comment="$(flac_gettag "$1" "COMMENT=")"
    trackno="$(flac_gettag "$1" "TRACKNUMBER=")"
    tracktotal="$(flac_gettag "$1" "TRACKTOTAL=")"
    genre="$(flac_gettag "$1" "GENRE=")"
    albumartist="$(flac_gettag "$1" "ALBUMARTIST=")"
    if [ -n "$tracktotal" ];
        then tracks="$trackno/$tracktotal"
    else
        tracks="$trackno"
    fi
    [ -n "$title" ] && mid3v2 -t "$title" "$2"
    [ -n "$artist" ] && mid3v2 -a "$artist" "$2"
    [ -n "$album" ] && mid3v2 -A "$album" "$2"
    [ -n "$year" ] && mid3v2 -y "$year" "$2"
    [ -n "$comment" ] && mid3v2 -c "$comment" "$2"
    [ -n "$tracks" ] && mid3v2 -T "$tracks" "$2"
    [ -n "$genre" ] && mid3v2 -g "$genre" "$2"
    [ -n "$albumartist" ] && mid3v2 --TPE2 "$albumartist" "$2"
    if [ -f "00 cover.jpg" ]; then
        eyeD3 --quiet --add-image="00 cover.jpg:FRONT_COVER:" "$2"
    elif [ -f "cover.jpg" ]; then
        eyeD3 --quiet --add-image="cover.jpg:FRONT_COVER:" "$2"
    fi
}

flac_transcode() {
    inpfile="${1}"
    outfile="${2}"
    wavfile="${outfile}.wav"
    
    # decode
    flac -s -o "$wavfile" -d "$inpfile"
    # encode
    lame --preset insane -S "$wavfile" "$outfile"
    rm -v "$wavfile"
}

while getopts "3fhV?" option; do
    case $option in
        3) mode="mp3" && ext="mp3" ;;
        f) mode="flac" && ext="flac" ;;
        h) print_help && exit ;;
        V) print_version && exit ;;
        "?") print_help && exit ;;
    esac
    shift $((OPTIND - 1))
done

# need exactly two arguments at this point
[ $# -ne 2 ] && die_invalidargumentcount
# no input file specified
[ -z "$1" -o ! -e "$1" ] && die_noinput "$1"
# no output file specified
if [ -z "$2" ] && die_nooutput
# input file and output file are the same
if [ "$1" = "$2" ] && die_inputoutputsame "$1" "$2"

if [ "$mode" ]; then
    eval transcode=\${mode}_transcode
    eval copytags=\${mode}_copytags
    $transcode "$1" "$2"
    $copytags "$1" "$2"
    exit 0
fi

if is_flac "$1"; then
    mode="flac" && ext="flac"
    flac_transcode "$1" "$2"
    flac_copytags "$1" "$2"
    exit 0
elif is_mp3 "$1"; then
    mode="mp3" && ext="mp3"
    mp3_transcode "$1" "$2"
    mp3_copytags "$1" "$2"
    exit 0
else
    shortname="$(basename "$1")"
    die_unknownfiletype "$shortname"
fi