attr_accessor :audio_track_1,  :audio_track_2,  :audio_track_3,  :audio_track_4,
                :audio_track_5,  :audio_track_6,  :audio_track_7,  :audio_track_8
  def self.generate_audio_tracks_accessors
    8.times do |i|
      define_method "audio_track_#{i+1}" do
        tracks = read_attribute :audio_tracks
        return tracks[i] if tracks
      end
      define_method "audio_track_#{i+1}=" do |a|
        tracks = read_attribute :audio_tracks
        tracks ||= []
        tracks[i] = a.to_i if a
        write_attribute :audio_tracks, tracks
      end
    end
  end
  generate_audio_tracks_accessors