Replace file name with metadata

convert.rb

require 'fileutils'
require 'taglib'

NAME = "©nam"
Dir.glob("./**/*.m4a").each do |f|
  TagLib::MP4::File.open(f) do |mp4|
    name = mp4.tag.item_list_map[NAME]
    name = name.to_string_list.first
    dir = File.dirname(f)
    name = "#{dir}/#{name}.m4a"
    FileUtils.mv(f, name) rescue nil
  end
end