KASUI m4a to mp3

conv.rb

# coding: utf-8

Dir['*.m4a'].each do |m4a|
  mp3 = File.basename(m4a, '.m4a') + '.mp3'
  cmd = "ffmpeg -i '#{m4a}' -acodec libmp3lame -ab 320 -ac 2 '#{mp3}'"
  puts cmd
  `#{cmd}`
end

m4a-mp3.sh

#!/bin/sh

for m4a in "$@"
do
  title=`basename "$m4a" .m4a`
  ffmpeg -i "$m4a" -acodec libmp3lame -ab 320 -ac 2 "$title".mp3
done