MIDI::Opus->new({
  'format' => 1,
  'ticks'  => 480,
  'tracks' => [   # 2 tracks...

    # Track #1 ...
    MIDI::Track->new({
      'type' => 'MTrk',
      'events' => [  # 2 events.
        ['set_tempo', 0, 500000],                 #       0  001-01-00-00  Tempo: q = 120
        ['time_signature', 0, 8, 2, 24, 8],       #       0  001-01-00-00  Time = 8/4, Click = 24, NoteQ = 8
      ]
    }),
    
    # Track #2 ...
    MIDI::Track->new({
      'type' => 'MTrk',
      'events' => [  # 44 events.
                                                  #       0  001-01-00-00  Time = 8/4, Click = 24, NoteQ = 8
        ['track_name', 0, ''],                    #       0  001-01-00-00
        ['patch_change', 0, 0, 0],                #       0  001-01-00-00  Channel 1, patch = Acoustic Grand
        ['control_change', 0, 0, 7, 100],         #       0  001-01-00-00  Main Volume = 100
        ['control_change', 0, 0, 10, 64],         #       0  001-01-00-00  Pan = 64
        ['note_on', 0, 0, 60, 100],               #       0  001-01-00-00  On:  C3
        ['note_off', 240, 0, 60, 127],            #     240  001-01-08-00  Off: C3
        ['note_on', 0, 0, 62, 100],               #     240  001-01-08-00  On:  D3
        ['note_off', 240, 0, 62, 127],            #     480  001-02-00-00  Off: D3
        ['note_on', 0, 0, 64, 100],               #     480  001-02-00-00  On:  E3
        ['note_off', 240, 0, 64, 127],            #     720  001-02-08-00  Off: E3
        ['note_on', 0, 0, 65, 100],               #     720  001-02-08-00  On:  F3
        ['note_off', 240, 0, 65, 127],            #     960  001-03-00-00  Off: F3
        ['note_on', 0, 0, 67, 100],               #     960  001-03-00-00  On:  G3
        ['note_off', 240, 0, 67, 127],            #    1200  001-03-08-00  Off: G3
        ['note_on', 0, 0, 69, 100],               #    1200  001-03-08-00  On:  A3
        ['note_off', 240, 0, 69, 127],            #    1440  001-04-00-00  Off: A3
        ['note_on', 0, 0, 71, 100],               #    1440  001-04-00-00  On:  B3
        ['note_off', 240, 0, 71, 127],            #    1680  001-04-08-00  Off: B3
        ['note_on', 0, 0, 72, 100],               #    1680  001-04-08-00  On:  C4
        ['note_off', 240, 0, 72, 127],            #    1920  001-05-00-00  Off: C4
        ['note_on', 0, 0, 74, 100],               #    1920  001-05-00-00  On:  D4
        ['note_off', 240, 0, 74, 127],            #    2160  001-05-08-00  Off: D4
        ['note_on', 0, 0, 76, 100],               #    2160  001-05-08-00  On:  E4
        ['note_off', 240, 0, 76, 127],            #    2400  001-06-00-00  Off: E4
        ['note_on', 0, 0, 76, 100],               #    2400  001-06-00-00  On:  E4
        ['note_off', 240, 0, 76, 127],            #    2640  001-06-08-00  Off: E4
        ['note_on', 0, 0, 74, 100],               #    2640  001-06-08-00  On:  D4
        ['note_off', 240, 0, 74, 127],            #    2880  001-07-00-00  Off: D4
        ['note_on', 0, 0, 72, 100],               #    2880  001-07-00-00  On:  C4
        ['note_off', 240, 0, 72, 127],            #    3120  001-07-08-00  Off: C4
        ['note_on', 0, 0, 71, 100],               #    3120  001-07-08-00  On:  B3
        ['note_off', 240, 0, 71, 127],            #    3360  001-08-00-00  Off: B3
        ['note_on', 0, 0, 69, 100],               #    3360  001-08-00-00  On:  A3
        ['note_off', 240, 0, 69, 127],            #    3600  001-08-08-00  Off: A3
        ['note_on', 0, 0, 67, 100],               #    3600  001-08-08-00  On:  G3
        ['note_off', 240, 0, 67, 127],            #    3840  002-01-00-00  Off: G3
        ['note_on', 0, 0, 65, 100],               #    3840  002-01-00-00  On:  F3
        ['note_off', 240, 0, 65, 127],            #    4080  002-01-08-00  Off: F3
        ['note_on', 0, 0, 64, 100],               #    4080  002-01-08-00  On:  E3
        ['note_off', 240, 0, 64, 127],            #    4320  002-02-00-00  Off: E3
        ['note_on', 0, 0, 62, 100],               #    4320  002-02-00-00  On:  D3
        ['note_off', 240, 0, 62, 127],            #    4560  002-02-08-00  Off: D3
        ['note_on', 0, 0, 60, 100],               #    4560  002-02-08-00  On:  C3
        ['note_off', 240, 0, 60, 127],            #    4800  002-03-00-00  Off: C3
      ]
    }),
    
  ]
});