如何以python和ffmpeg或类似格式读取实时麦克风音频音量 [英] How to read realtime microphone audio volume in python and ffmpeg or similar

问题描述

我正在尝试近实时读取音量，该音量来自Python中USB麦克风的音频.

I'm trying to read, in near-realtime, the volume coming from the audio of a USB microphone in Python.

我有一些作品，但不知道如何将它们组合在一起.

I have the pieces, but can't figure out how to put it together.

如果我已经有一个.wav文件，我可以很简单地使用 wavefile 读取它:

If I already have a .wav file, I can pretty simply read it using wavefile:

from wavefile import WaveReader

with WaveReader("/Users/rmartin/audio.wav") as r:
    for data in r.read_iter(size=512):
        left_channel = data[0]
        volume = np.linalg.norm(left_channel)
        print volume

这很好用，但是我想实时处理来自麦克风的音频，而不是来自文件的音频.

This works great, but I want to process the audio from the microphone in real-time, not from a file.

所以我的想法是使用ffmpeg之类的东西将实时输出PIPE实时输入到WaveReader中，但是我的Byte知识却有些缺乏.

So my thought was to use something like ffmpeg to PIPE the real-time output into WaveReader, but my Byte knowledge is somewhat lacking.

import subprocess
import numpy as np

command = ["/usr/local/bin/ffmpeg",
            '-f', 'avfoundation',
            '-i', ':2',
            '-t', '5',
            '-ar', '11025',
            '-ac', '1',
            '-acodec','aac', '-']

pipe = subprocess.Popen(command, stdout=subprocess.PIPE, bufsize=10**8)
stdout_data = pipe.stdout.read()
audio_array = np.fromstring(stdout_data, dtype="int16")

print audio_array

看起来很漂亮，但是没有做太多.它失败，并出现 [NULL @ 0x7ff640016600]无法为'pipe:'错误找到合适的输出格式.

That looks pretty, but it doesn't do much. It fails with a [NULL @ 0x7ff640016600] Unable to find a suitable output format for 'pipe:' error.

鉴于我只需要检查音频的音量，我认为这是一件相当简单的事情.

I assume this is a fairly simple thing to do given that I only need to check the audio for volume levels.

有人知道如何简单地做到这一点吗? FFMPEG不是必需的，但确实需要在OSX& Linux.

Anyone know how to accomplish this simply? FFMPEG isn't a requirement, but it does need to work on OSX & Linux.

推荐答案

感谢@Matthias建议使用sounddevice模块.这正是我所需要的.

Thanks to @Matthias for the suggestion to use the sounddevice module. It's exactly what I need.

对于后代，这是一个工作示例，该示例将实时音频电平打印到外壳:

For posterity, here is a working example that prints real-time audio levels to the shell:

# Print out realtime audio volume as ascii bars

import sounddevice as sd
import numpy as np

def print_sound(indata, outdata, frames, time, status):
    volume_norm = np.linalg.norm(indata)*10
    print ("|" * int(volume_norm))

with sd.Stream(callback=print_sound):
    sd.sleep(10000)

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