使用 PyAudio 作为振荡器删除/控制点击声

Question

当它运行时，音调之间会发出咔嗒声。我不太介意点击声——它有令人愉快的节奏。那是说...

• 我希望能够在不需要时消除这种咔哒声。
• 更好的是，如果能够以某种方式控制点击声（音量等），那就太好了。

我已经看到这个线程，但还没有弄清楚如何将其应用于我的问题： How to remove pops from concatenated sound data in PyAudio

有任何想法吗？谢谢你的时间！

import numpy
import pyaudio
import math
import random


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


def play_tone(stream, frequency, length, rate=44100):
    chunks = []
    chunks.append(sine(frequency, length, rate))

    chunk = numpy.concatenate(chunks) * .25

    stream.write(chunk.astype(numpy.float32).tostring())


def bassline():
        frequency = 300
        for i in range(1000000):
            play_tone(stream, frequency, .15)
            change = random.choice([-75, -75, -10, 10, 2, 3, 100, -125])
            print (frequency)
            if frequency < 0:
                frequency = random.choice([100, 200, 250, 300])
            else:
                frequency = frequency + change 

if __name__ == '__main__':
    p = pyaudio.PyAudio()
    stream = p.open(format=pyaudio.paFloat32,
                    channels=1, rate=44100, output=4)

bassline()

/编辑

我已经绘制了音调，看起来不连续性存在于每个音调的开始和结束阶段之间的关系中。

第一声

第二声

有什么想法可以解决这个问题吗？

Answer 1

谢谢埃兹和马蒂亚斯。​

最后，我通过在几百毫秒的时间内淡入和淡出每个音调来解决这个问题。这也是控制点击声音的好方法。越接近fade，0咔哒声越大。

import math
import numpy
import pyaudio


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


def play_tone(stream, frequency, length, rate=44100):
    chunks = [sine(frequency, length, rate)]

    chunk = numpy.concatenate(chunks) * 0.25

    fade = 200.

    fade_in = numpy.arange(0., 1., 1/fade)
    fade_out = numpy.arange(1., 0., -1/fade)

    chunk[:fade] = numpy.multiply(chunk[:fade], fade_in)
    chunk[-fade:] = numpy.multiply(chunk[-fade:], fade_out)

    stream.write(chunk.astype(numpy.float32).tostring())


def test():
    test_freqs = [50, 100, 200, 400, 800, 1200, 2000, 3200]

    for i in range(2):
        for freq in test_freqs:
            play_tone(stream, freq, 1)


if __name__ == '__main__':
    p = pyaudio.PyAudio()
    stream = p.open(format=pyaudio.paFloat32,
                    channels=1, rate=44100, output=1)


test()