PyAudio - 如何将波形文件混合成连续流

Question

我想编写一个非常基本的应用程序，将音频从麦克风传递到扬声器。如https://people.csail.mit.edu/hubert/pyaudio/ 所述，使用 pyaudio 非常简单。

def passthrough():
    WIDTH = 2
    CHANNELS = 1
    RATE = 44100

    p = pyaudio.PyAudio()

    def callback(in_data, frame_count, time_info, status):

        return (in_data, pyaudio.paContinue)

    stream = p.open(format=p.get_format_from_width(WIDTH),
                    channels=CHANNELS,
                    rate=RATE,
                    input=True,
                    output=True,
                    stream_callback=callback)

    stream.start_stream()

    while stream.is_active():
        time.sleep(0.1)

    stream.stop_stream()
    stream.close()

    p.terminate()

但现在我尝试在事件发生时将波形文件混合到此流中。这就是我现在卡住的地方。播放波形文件似乎也很容易。

def play_wave(wav_file):
    wf = wave.open(wav_file, 'rb')

    sample_width=wf.getsampwidth()
    channels=wf.getnchannels()
    rate=wf.getframerate()
    second=sample_width*channels*rate

    def callback(in_data, frame_count, time_info, status):
        data = wf.readframes(frame_count)
        return (data, pyaudio.paContinue)

    p = pyaudio.PyAudio()

    stream = p.open(format=p.get_format_from_width(sample_width),
                channels=channels,
                rate=int(rate),
                output=True,
                stream_callback=callback)
    stream.start_stream()

    while stream.is_active():
        time.sleep(0.1)

    stream.stop_stream()
    stream.close()
    wf.close()

    p.terminate()

这个时候，我有两个问题。

1. 如何将波形输出混合到连续流中
2. 如何触发 1. 基于事件

希望有人可以点亮我现在所在的黑暗地下室。

编辑：假设波形文件具有相同数量的通道和相同的速率，因此无需转换。

Answer 1

将throughput() 函数移入线程后，它会按预期工作。当我昨天尝试这个时，我只是搞砸了线程启动（从 init 调用吞吐量，而不是在 run() 方法中）。

这里是完整的工作代码。

import pyaudio
import wave
import threading
import time

class AudioPass(threading.Thread):
    def __init__(self):
        threading.Thread.__init__(self)
    def run(self):
        self.passthrough()
    def passthrough(self):
        WIDTH = 2
        CHANNELS = 1
        RATE = 44100

        p = pyaudio.PyAudio()

        def callback(in_data, frame_count, time_info, status):

            return (in_data, pyaudio.paContinue)

        stream = p.open(format=p.get_format_from_width(WIDTH),
                        channels=CHANNELS,
                        rate=RATE,
                        input=True,
                        output=True,
                        stream_callback=callback)

        stream.start_stream()

        while stream.is_active():
            time.sleep(0.1)

        stream.stop_stream()
        stream.close()

        p.terminate()


def play_wave(wav_file):
    wf = wave.open(wav_file, 'rb')

    sample_width=wf.getsampwidth()
    channels=wf.getnchannels()
    rate=wf.getframerate()
    second=sample_width*channels*rate

    def callback(in_data, frame_count, time_info, status):
        data = wf.readframes(frame_count)
        return (data, pyaudio.paContinue)

    p = pyaudio.PyAudio()

    stream = p.open(format=p.get_format_from_width(sample_width),
                channels=channels,
                rate=int(rate),
                output=True,
                stream_callback=callback)
    stream.start_stream()

    while stream.is_active():
        time.sleep(0.1)

    stream.stop_stream()
    stream.close()
    wf.close()

    p.terminate()

thread = AudioPass()
thread.start()
play_wave('C:/bell.wav')

稍后我也会尝试今天一位同事建议的另一种方式，如果它也很好，我也会把它放在这里作为替代方案。使用线程方式很好，因为我可以对流和 wav 文件使用不同的速率。

Answer 2

一位同事提供了以下解决方案，这是一种非常原始的方法，但它有效并且有助于理解这个 pyaudio 的工作原理。

import time
import pyaudio
import numpy
WIDTH = 2
CHANNELS = 1
RATE = 44100
p = pyaudio.PyAudio()
SINE_WAVE_FREQUENCY = 440.0 # In Hz
SINE_WAVE_DURATION = 5.0 # In seconds
SINE_WAVE_VOLUME = 0.5
SINE_WAVE = (numpy.sin(2 * numpy.pi * numpy.arange(RATE * SINE_WAVE_DURATION) * SINE_WAVE_FREQUENCY / RATE)).astype(numpy.float32) * SINE_WAVE_VOLUME
def loopback(in_data, frame_count, time_info, status):
        return (in_data, pyaudio.paContinue)
stream = p.open(format=p.get_format_from_width(WIDTH), channels=CHANNELS, rate=RATE, input=True, output=True, stream_callback=loopback)
stream.start_stream()
def playsine():
        sinestream = p.open(format=pyaudio.paFloat32, channels=1, rate=RATE, output=True)
        sinestream.write(SINE_WAVE)
        sinestream.stop_stream()
        sinestream.close()
while True:
        input("Press enter to play a sine wave")
        playsine()