compress mp3 by 48k bitrate and remove title metadata

compress.sh

#!/usr/bin/env bash

set -o errexit
set -o pipefail
set -o nounset

OIFS="$IFS"
IFS=$'\n'

info () {
    printf "\r  [\033[0;34m .. \033[0m] $1\n"
}

success () {
    printf "\r  [\033[0;32m OK \033[0m] $1\n"
}

fail () {
    printf "\r  [\033[0;31mFAIL\033[0m] $1\n"
    echo ''
    exit 1
}

if ! [ -x "$(command -v ffmpeg)" ]; then
    fail "ffmpeg not found."
fi

for file in $(find . -type f -name "*.mp3")
do
    info "Processing ${file}"
    start=`date +%s`
    oldSize=$(($(stat -f "%z" $file) / 1024))
    tempFile=${file}.tmp

    # compress to 48k bitrate and remove all metadata
    #ffmpeg -y -i $file -map_metadata -1 -ab 48k -f mp3 $tempFile
    # compress to 48k bitrate and remove title metadata
    ffmpeg -v error -y -i $file -metadata title= -ab 48k -f mp3 $tempFile

    newSize=$(($(stat -f "%z" $tempFile) / 1024))
    end=`date +%s`
    exeTime=$(($end - $start))

    if [[ $newSize -lt $oldSize ]]; then
        diff=$(($oldSize - $newSize))
        pct=$(($diff * 100 / $oldSize))
        rm $file
        mv $tempFile $file
        success "${oldSize} KB -> ${newSize} KB (-${pct} pct) (${exeTime}s)"
    else
        rm $tempFile
        success "${oldSize} KB -> No change (${exeTime}s)"
    fi
done