如何改变品红音符序列的节奏?

Question

我试过改变qpm。但这改变不了什么。我想改变音符序列的节奏。我正在做Colab，我的笔记本可以在这里找到。

    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

您可以在github中的magenta/demos中找到几个示例。你可以找到这个解。希望能有所帮助:

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)

Answer 2

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.

要使它快2倍，你可以使用0.5的stretch_factor:

from note_seq.sequences_lib import stretch_note_sequence
faster_twinkle_twinkle = stretch_note_sequence(twinkle_twinkle, 0.5)