Raspberry pi:从python代码生成和播放音调(使用sox) [英] Raspberry pi: generate and play tone from python code (with sox)

问题描述

我正在使用python 3使用Raspberry，TKinter和sox构建一个简单的GUI. 每次按下GUI中的按钮时，我都想播放一种动态产生的音调.这是代码:

I am building a simple GUI with Raspberry, TKinter, and sox, using python 3. I want to play a tone, generated on the fly, every time a button in the GUI is pressed. Here's the code:

from Tkinter import Tk, Label, Button
import os

class MyFirstGUI:
    def __init__(self, master):
        self.master = master
        master.title("Random Tone Generator")

        self.label = Label(master, text="Press Generate and enjoy")
        self.label.pack()

        self.generate_button = Button(master, text="Generate", command=self.generate)
        self.generate_button.pack()

        self.close_button = Button(master, text="Close", command=master.quit)
        self.close_button.pack()

    def generate(self):
        os.system('play -n -c1 synth 3 sine 500')

root = Tk()
my_gui = MyFirstGUI(root)
root.mainloop()

这是终端到此脚本的呼叫

Here is the call from terminal to this script

sudo python /home/pi/Desktop/soundtest.py

在这里，如果我尝试按"Generate"按钮，就会收到错误消息

And here the error I get if I try to push the button "Generate"

play FAIL formats: can't open output file `default': select_format error: Operation not permitted

如果我尝试相同的命令('play -n -c1 synth 3 sine 500')，它将按预期工作.

If I try the same command ('play -n -c1 synth 3 sine 500') it works as expected.

我搜索了几个小时，然后尝试使用 subprocess 解决方案，该解决方案会返回相同的问题，以及与播放文件有关的解决方案，而我需要当场发出提示音，因为将来它们将是随机生成的.

I searched for few hours now and I tried solutions using subprocess, which give back the same problem, and solutions related to playing files, while I need to generate tones on the spot because in the future they will be randomly generated.

我的问题归结为: 1)为什么在终端中运行的命令在python脚本中不起作用 2)如何使其起作用，以便可以直接从脚本生成音调? 我在某个地方读到了我找不到的东西，可能在从脚本进行调用的过程中可能需要指定音频驱动程序.但是我不知道怎么办.

My question boils down to: 1) why the command that works in the terminal does not work within the python script 2) how do I make it work so that I can generate tones directly from the script? I read somewhere I can't find anymore that one might need to specify the audio driver during the call from the script. But I wouldn't know how.

我安装了HiFiberry DAC + pro声卡，该声卡自动设置为默认声卡(而不是vc4-hdmi)

I have an HiFiberry DAC+ pro sound card installed, which is automatically set to be the default one (instead of the vc4-hdmi)

**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi [vc4-hdmi], device 0: MAI PCM vc4-hdmi-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: sndrpihifiberry [snd_rpi_hifiberry_dacplus], device 0: HiFiBerry DAC+ Pro HiFi pcm512x-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

谢谢 蚂蚁

推荐答案

找到了解决方案.

我需要指定要使用的声卡，并且通过更改线路来做到这一点

I needed to specify the sound card to use and I did so by changing the line

os.system('play -n -c1 synth 3 sine 500')

进入此

os.system("AUDIODRIVER=alsa AUDIODEV=hw:1,0 play -n -c1 synth 3 sine 500")

其中 AUDIODEV = hw:1,0 是我的声卡的编号， aplay -l

where the AUDIODEV=hw:1,0 is the number of my sound card derived from aplay -l

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