pyaudio可以同时播放两个音符吗? [英] Is it possible to play two notes at once with pyaudio?

问题描述

是否可以使用 pyaudio 演奏和弦?

Is it possible to play chords using pyaudio?

推荐答案

当然！

只需生成结果并将其传递给播放器即可.

Just generate the result and pass it to the player.

本文介绍了一种方法去做.

这里是示例代码，以防链接中的文章更改或失效:

Here is the example code in case the article at the link changes or goes dead:

import math
import numpy
import pyaudio
import itertools
from scipy import interpolate
from operator import itemgetter

# https://davywybiral.blogspot.com/2010/09/procedural-music-with-pyaudio-and-numpy.html

class Note:

  NOTES = ['c','c#','d','d#','e','f','f#','g','g#','a','a#','b']

  def __init__(self, note, octave=4):
    self.octave = octave
    if isinstance(note, int):
      self.index = note
      self.note = Note.NOTES[note]
    elif isinstance(note, str):
      self.note = note.strip().lower()
      self.index = Note.NOTES.index(self.note)

  def transpose(self, halfsteps):
    octave_delta, note = divmod(self.index + halfsteps, 12)S
    return Note(note, self.octave + octave_delta)

  def frequency(self):
    base_frequency = 16.35159783128741 * 2.0 ** (float(self.index) / 12.0)
    return base_frequency * (2.0 ** self.octave)

  def __float__(self):
    return self.frequency()


class Scale:

  def __init__(self, root, intervals):
    self.root = Note(root.index, 0)
    self.intervals = intervals

  def get(self, index):
    intervals = self.intervals
    if index < 0:
      index = abs(index)
      intervals = reversed(self.intervals)
    intervals = itertools.cycle(self.intervals)
    note = self.root
    for i in range(index):
      note = note.transpose(next(intervals))
    return note

  def index(self, note):
    intervals = itertools.cycle(self.intervals)
    index = 0
    x = self.root
    while x.octave != note.octave or x.note != note.note:
      x = x.transpose(next(intervals))
      index += 1
    return index

  def transpose(self, note, interval):
    return self.get(self.index(note) + interval)


def sine(frequency, length, rate):
  length = int(length * rate)
  factor = float(frequency) * (math.pi * 2) / rate
  return numpy.sin(numpy.arange(length) * factor)

def shape(data, points, kind='slinear'):
    items = points.items()
    sorted(items,key=itemgetter(0))
    keys = list(map(itemgetter(0), items))
    vals = list(map(itemgetter(1), items))
    interp = interpolate.interp1d(keys, vals, kind=kind)
    factor = 1.0 / len(data)
    shape = interp(numpy.arange(len(data)) * factor)
    return data * shape

def harmonics1(freq, length):
  a = sine(freq * 1.00, length, 44100)
  b = sine(freq * 2.00, length, 44100) * 0.5
  c = sine(freq * 4.00, length, 44100) * 0.125
  return (a + b + c) * 0.2

def harmonics2(freq, length):
  a = sine(freq * 1.00, length, 44100)
  b = sine(freq * 2.00, length, 44100) * 0.5
  return (a + b) * 0.2

def pluck1(note):
  chunk = harmonics1(note.frequency(), 2)
  return shape(chunk, {0.0: 0.0, 0.005: 1.0, 0.25: 0.5, 0.9: 0.1, 1.0:0.0})

def pluck2(note):
  chunk = harmonics2(note.frequency(), 2)
  return shape(chunk, {0.0: 0.0, 0.5:0.75, 0.8:0.4, 1.0:0.1})

def chord(n, scale):
  root = scale.get(n)
  third = scale.transpose(root, 2)
  fifth = scale.transpose(root, 4)
  return pluck1(root) + pluck1(third) + pluck1(fifth)

root = Note('A', 3)
scale = Scale(root, [2, 1, 2, 2, 1, 3, 1])

chunks = []
chunks.append(chord(21, scale))
chunks.append(chord(19, scale))
chunks.append(chord(18, scale))
chunks.append(chord(20, scale))
chunks.append(chord(21, scale))
chunks.append(chord(22, scale))
chunks.append(chord(20, scale))
chunks.append(chord(21, scale))

chunks.append(chord(21, scale) + pluck2(scale.get(38)))
chunks.append(chord(19, scale) + pluck2(scale.get(37)))
chunks.append(chord(18, scale) + pluck2(scale.get(33)))
chunks.append(chord(20, scale) + pluck2(scale.get(32)))
chunks.append(chord(21, scale) + pluck2(scale.get(31)))
chunks.append(chord(22, scale) + pluck2(scale.get(32)))
chunks.append(chord(20, scale) + pluck2(scale.get(29)))
chunks.append(chord(21, scale) + pluck2(scale.get(28)))

chunk = numpy.concatenate(chunks) * 0.25

p = pyaudio.PyAudio()
stream = p.open(format=pyaudio.paFloat32, channels=1, rate=44100, output=1)
stream.write(chunk.astype(numpy.float32).tostring())
stream.close()
p.terminate()

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