Python 简单音频生成器

Question

寻找一个（简单的）Python 音调生成器，用于在带有 USB 声卡的 RaspberryPi 上运行的以下脚本。需要动态音调开/关和频率更改。

import serial, time

ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=0.1)

def monitor(inp=0):
    if inp != inpold:
        if inp != 0:
            ser.setDTR(1)   # LED on (GPIO?)
                # start tone here, generate tone forever or change tone freq
        else:
            ser.setDTR(0)   # LED off
                # stop tone without clicks
        inpold = inp

while True:
    time.sleep(0.01)        # min length tone pulse 10 milliseconds
    input = ser.getCTS()    # or GPIO input
    monitor(input)

Answer 1

所以我找到了几种方法来做到这一点，我将按可行性顺序排列它们（首先最容易应用）：-

---

关于语气的假设：-

• 波形类型 = 正弦波

• 频率 = 440Hz

---

方式1（离线曲目，没有声音设备/后端麻烦）

1- 使用 Audacity 软件（或任何类似软件）创建一个 特定的音调并将其导出到文件。

2- 在 Audacity 中，从上面的选项卡中选择“生成”，然后选择 “音调”并在频率旁边输入 440。

3- 从 Audacity 中，从上面的选项卡中选择“文件”，然后选择“导出”并选择 导出为您喜欢的任何扩展名，最好是 mp3。 '输出.mp3'

4- pip install 播放声音

5- 在 python 中

import playsound
playsound.playsound('out.mp3')

方式2（灵活，但必须确保后端工作正常）

1-pip 安装 pygame

2-如果您在 Linux 环境下工作，请确保安装以下库

libsdl1.2-dev libsdl-image1.2-dev libsdl-mixer1.2-dev libsdl-ttf2.0-dev

3- 在 python 中

import numpy
import pygame

sampleRate = 44100
freq = 440

pygame.mixer.init(44100,-16,2,512)
# sampling frequency, size, channels, buffer

# Sampling frequency
# Analog audio is recorded by sampling it 44,100 times per second, 
# and then these samples are used to reconstruct the audio signal 
# when playing it back.

# size
# The size argument represents how many bits are used for each 
# audio sample. If the value is negative then signed sample 
# values will be used.

# channels
# 1 = mono, 2 = stereo

# buffer
# The buffer argument controls the number of internal samples 
# used in the sound mixer. It can be lowered to reduce latency, 
# but sound dropout may occur. It can be raised to larger values
# to ensure playback never skips, but it will impose latency on sound playback. 

arr = numpy.array([4096 * numpy.sin(2.0 * numpy.pi * freq * x / sampleRate) for x in range(0, sampleRate)]).astype(numpy.int16)
arr2 = numpy.c_[arr,arr]
sound = pygame.sndarray.make_sound(arr2)
sound.play(-1)
pygame.time.delay(1000)
sound.stop()

方式3（正弦波）

如果您只需要正弦波，请使用此

1-pip 安装 pysine

2-如果您在 Linux 环境下工作，请确保安装以下库

portaudio19-dev

但是，如果您在 Windows 环境下工作，请确保使用 pipwin 安装它

pipwin install pysine

3- 在 python 中

import pysine
pysine.sine(frequency=440.0, duration=1.0) 

Answer 2

尝试

pysinewave

。它允许您开始、停止和平滑地改变音调的音调和音量。
示例：

from pysinewave import SineWave
import time

sinewave = SineWave(pitch = 12)
sinewave.play()
time.sleep(1)
sinewave.stop()

Answer 3

花费大量时间使用 pyaudio，但使用 pygame 非常简单。谢谢 http://shallowsky.com/blog/programming/python-play-chords.html

import pygame, pygame.sndarray
import numpy
import scipy.signal
from time import sleep

sample_rate = 48000
pygame.mixer.pre_init(sample_rate, -16, 1, 1024)
pygame.init()

def square_wave(hz, peak, duty_cycle=.5, n_samples=sample_rate):
    t = numpy.linspace(0, 1, 500 * 440/hz, endpoint=False)
    wave = scipy.signal.square(2 * numpy.pi * 5 * t, duty=duty_cycle)
    wave = numpy.resize(wave, (n_samples,))
    return (peak / 2 * wave.astype(numpy.int16))

def audio_freq(freq = 800):
    global sound
    sample_wave = square_wave(freq, 4096)
    sound = pygame.sndarray.make_sound(sample_wave)
# TEST
audio_freq()
sound.play(-1)
sleep(0.5)
sound.stop()
audio_freq(1000)
#sleep(1)
sound.play(-1)
sleep(2)
sound.stop()
sleep(1)
sound.play(-1)
sleep(0.5)

Answer 4

有一个使用 PySDL2 实时生成音调的示例。 UP和DOWN键用于改变频率。

import sys
import sdl2
import sdl2.ext
import math
import struct
import ctypes

basefreq = 110
nframes = 0

@ctypes.CFUNCTYPE(None, ctypes.c_void_p, ctypes.POINTER(sdl2.Uint8), ctypes.c_int)
def playNext(notused, stream, len):
    global nframes
    for i in range(0, len, 4):
        t = (nframes + i) / 44100
        left  = int(math.sin(2 * math.pi * t * (basefreq - 1)) * 32000)
        right = int(math.sin(2 * math.pi * t * (basefreq + 1)) * 32000)
        stream[i]   = left & 0xff
        stream[i+1] = (left >> 8) & 0xff
        stream[i+2] = right & 0xff
        stream[i+3] = (right >> 8) & 0xff
    nframes += len

def initAudio():
    spec = sdl2.SDL_AudioSpec(0, 0, 0, 0)
    spec.callback = playNext
    spec.freq = 44100
    spec.format = sdl2.AUDIO_S16SYS
    spec.channels = 2
    spec.samples = 1024

    devid = sdl2.SDL_OpenAudioDevice(None, 0, spec, None, 0)
    sdl2.SDL_PauseAudioDevice(devid, 0)

def run():
    global basefreq
    sdl2.SDL_Init(sdl2.SDL_INIT_AUDIO | sdl2.SDL_INIT_TIMER | sdl2.SDL_INIT_VIDEO)
    window = sdl2.ext.Window("Tone Generator", size=(800, 600))
    window.show()
    running = True
    initAudio()
    while running:
        events = sdl2.ext.get_events()
        for event in events:
            if event.type == sdl2.SDL_QUIT:
                running = False
                break
            elif event.type == sdl2.SDL_KEYDOWN:
                if event.key.keysym.sym == sdl2.SDLK_UP:
                    basefreq *= 2
                elif event.key.keysym.sym == sdl2.SDLK_DOWN:
                    basefreq /= 2
               break
        sdl2.SDL_Delay(20)
    return 0

if __name__ == "__main__":
    sys.exit(run())