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I tried changing qpm. But it doesn't change anything. I want to change the tempo of the notes sequence. I am working on Colab, my notebook can be found here.

    from note_seq.protobuf import music_pb2
    from note_seq import sequences_lib
    
    twinkle_twinkle = music_pb2.NoteSequence()
    
    # Add the notes to the sequence.
    twinkle_twinkle.notes.add(pitch=60, start_time=0.0, end_time=0.5, velocity=80)
    twinkle_twinkle.notes.add(pitch=60, start_time=0.5, end_time=1.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=67, start_time=1.0, end_time=1.5, velocity=80)
    twinkle_twinkle.notes.add(pitch=67, start_time=1.5, end_time=2.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=69, start_time=2.0, end_time=2.5, velocity=80)
    twinkle_twinkle.notes.add(pitch=69, start_time=2.5, end_time=3.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=67, start_time=3.0, end_time=4.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=65, start_time=4.0, end_time=4.5, velocity=80)
    twinkle_twinkle.notes.add(pitch=65, start_time=4.5, end_time=5.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=64, start_time=5.0, end_time=5.5, velocity=80)
    twinkle_twinkle.notes.add(pitch=64, start_time=5.5, end_time=6.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=62, start_time=6.0, end_time=6.5, velocity=80)
    twinkle_twinkle.notes.add(pitch=62, start_time=6.5, end_time=7.0, velocity=80)
    twinkle_twinkle.notes.add(pitch=60, start_time=7.0, end_time=8.0, velocity=80) 
    twinkle_twinkle.total_time = 8
    
    twinkle_twinkle.tempos.add(qpm=120);
    
    
    # This is a colab utility method that visualizes a NoteSequence.
    note_seq.plot_sequence(twinkle_twinkle)
    
    # This is a colab utility method that plays a NoteSequence.
    note_seq.play_sequence(twinkle_twinkle,synth=note_seq.fluidsynth)
Khalid Saifullah
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Janith Bandara
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2 Answers2

1

You can find several examples at magenta/demos in github. You can find there this solution. Hope it helps:

from note_seq.protobuf import music_pb2
import copy

def change_tempo(note_sequence, new_tempo):
    new_sequence = copy.deepcopy(note_sequence)
    ratio = note_sequence.tempos[0].qpm / new_tempo
    for note in new_sequence.notes:
        note.start_time = note.start_time * ratio
        note.end_time = note.end_time * ratio
    new_sequence.tempos[0].qpm = new_tempo
    return new_sequence

twinkle_twinkle = music_pb2.NoteSequence()

# Add the notes to the sequence.
twinkle_twinkle.notes.add(pitch=60, start_time=0.0, end_time=0.5, velocity=80)
twinkle_twinkle.notes.add(pitch=60, start_time=0.5, end_time=1.0, velocity=80)
twinkle_twinkle.notes.add(pitch=67, start_time=1.0, end_time=1.5, velocity=80)
twinkle_twinkle.notes.add(pitch=67, start_time=1.5, end_time=2.0, velocity=80)
twinkle_twinkle.notes.add(pitch=69, start_time=2.0, end_time=2.5, velocity=80)
twinkle_twinkle.notes.add(pitch=69, start_time=2.5, end_time=3.0, velocity=80)
twinkle_twinkle.notes.add(pitch=67, start_time=3.0, end_time=4.0, velocity=80)
twinkle_twinkle.notes.add(pitch=65, start_time=4.0, end_time=4.5, velocity=80)
twinkle_twinkle.notes.add(pitch=65, start_time=4.5, end_time=5.0, velocity=80)
twinkle_twinkle.notes.add(pitch=64, start_time=5.0, end_time=5.5, velocity=80)
twinkle_twinkle.notes.add(pitch=64, start_time=5.5, end_time=6.0, velocity=80)
twinkle_twinkle.notes.add(pitch=62, start_time=6.0, end_time=6.5, velocity=80)
twinkle_twinkle.notes.add(pitch=62, start_time=6.5, end_time=7.0, velocity=80)
twinkle_twinkle.notes.add(pitch=60, start_time=7.0, end_time=8.0, velocity=80) 
twinkle_twinkle.total_time = 8

twinkle_twinkle.tempos.add(qpm=60);

# New note sequence with changed tempo
twinkle_twinkle_tempo_changed = change_tempo(twinkle_twinkle, new_tempo = 130)

# This is a colab utility method that visualizes a NoteSequence.
note_seq.plot_sequence(twinkle_twinkle)

# This is a colab utility method that plays a NoteSequence.
note_seq.play_sequence(twinkle_twinkle,synth=note_seq.fluidsynth)
note_seq.play_sequence(twinkle_twinkle_tempo_changed,synth=note_seq.fluidsynth)
edu Sanmi
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0

Use stretch_sequence_note():

Apply a constant temporal stretch to a NoteSequence proto.
  Args:
    note_sequence: The NoteSequence to stretch.
    stretch_factor: How much to stretch the NoteSequence. Values greater than
      one increase the length of the NoteSequence (making it "slower"). Values
      less than one decrease the length of the NoteSequence (making it
      "faster").
    in_place: If True, the input note_sequence is edited directly.
  Returns:
    A stretched copy of the original NoteSequence.

To make it 2x faster you can use a stretch_factor of 0.5 like this:

from note_seq.sequences_lib import stretch_note_sequence

faster_twinkle_twinkle = stretch_note_sequence(twinkle_twinkle, 0.5)
Hernán Alarcón
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