如何改变洋红色音符序列的速度？

Question

我尝试更改 qpm。但这并没有改变任何东西。我想改变音符序列的节奏。我在 Colab 上工作，可以找到我的笔记本 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)

Answer 1

使用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.

要使其速度提高 2 倍，您可以像这样使用 0.5 的 stretch_factor：

from note_seq.sequences_lib import stretch_note_sequence

faster_twinkle_twinkle = stretch_note_sequence(twinkle_twinkle, 0.5)

Answer 2

您可以在 github 中的 magenta/demos 找到几个示例。你可以在那里找到这个解决方案。希望对您有所帮助：

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)

如何改变洋红色音符序列的速度？

How to Change Tempo of a Notes Sequence in Magenta?

python

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