convert_force_aac.sh

#!/usr/bin/env bash
set -xeu

root_dir=`cd $(dirname $0) && pwd`

IFS='
'

function convert_aac () {
    local audio_file="$1"
    local audio_file_m4a="$2"

    echo "> convert $audio_file"

    # 画像抽出、無いなら無いでOK
    echo "$(ffmpeg -hide_banner \
        -i "${audio_file}" \
        "cover.jpg")"

    # convert
    ffmpeg -hide_banner \
        -i "${audio_file}" \
        -vn \
        -codec:a aac \
        -ab 320k \
        "${audio_file_m4a}"

    # coverがあるなら付与
    if [ -e "cover.jpg" ]; then
        # jpgはjpgでもAtomicParsleyが駄目なjpgあるらしいのでconvertして確実にやる
        convert cover.jpg must_jpg_cover.jpg
        AtomicParsley "${audio_file_m4a}" --artwork must_jpg_cover.jpg --overWrite
        rm cover.jpg must_jpg_cover.jpg
    fi
}

audio_files=$(find . -type f | grep -vi hi-res)

for audio_file in ${audio_files[@]}; do
    # 非対象ファイルたち
    if [ -z "$(echo $audio_file | grep -v -E '\.(m4a|sh|jpg)')" ]; then
        continue
    fi

    audio_file_m4a="${audio_file%.*}.m4a"

    # convert済み
    if [ -e "${audio_file_m4a}" ]; then
        echo skip
        continue
    fi

    # convert
    echo convert_aac "${audio_file}" "${audio_file_m4a}"

done

alac_dirs=$(find . -type d -name 'M4A')

for alac_dir in ${alac_dirs[@]}; do
    echo $alac_dir

    cd $alac_dir
    for audio_file_alac in `find . -type f`; do
        echo $audio_file_alac
        # 非対象ファイルたち
        if [ -z "$(echo $audio_file_alac | grep -E '\.m4a')" ]; then
            continue
        fi

        audio_file_aac="../AAC/${audio_file_alac}"
        mkdir -p "$( dirname ${audio_file_aac})"

        # convert済み
        if [ -e "${audio_file_aac}" ]; then
            echo skip
            continue
        fi

        # convert
        convert_aac "${audio_file_alac}" "${audio_file_aac}"
    done

    cd $root_dir
done