python – 支持ASIO的多通道PyAudio

2024-03-31 14:57:34

我试图在Win7上使用PyAudio与PreSonus AudioBox 1818VSL连接,但是在一次录制超过2个通道(立体声)时遇到一些麻烦. PreSonus驱动程序创建许多立体声输入音频设备(例如立体声通道1和2,3和4等)和18输入通道ASIO设备.我可以毫无问题地从任何立体声设备录制.为了最小化延迟并从>记录2个频道,我正在尝试使用ASIO设备.

我一直在使用http://www.lfd.uci.edu/~gohlke/pythonlibs/#pyaudio的PyAudio构建,它已经编译了对ASIO,DS,WMME,WASAPI,WDMKS的支持.

调用pyaudio_handle.is_format_supported()表明ASIO设备支持44.1,48和96 kHz的8到32位数据.

下面是pa.get_device_info_by_index返回的字典(32)

{'defaultHighInputLatency': 0.046439909297052155,
'defaultHighOutputLatency': 0.046439909297052155,
'defaultLowInputLatency': 0.046439909297052155,
'defaultLowOutputLatency': 0.046439909297052155,
'defaultSampleRate': 44100.0,
'hostApi': 2L,
'index': 32,
'maxInputChannels': 18L,
'maxOutputChannels': 18L,
'name': u'AudioBox ASIO Driver',
'structVersion': 2L}

下面是我用来创建PyAudio输入流的代码.回调函数只是将数据推入列表并返回pyaudio.paContinue,直到我得到我想要的样本量,然后它返回pyaudio.paComplete.

pyaudio_handle = pyaudio.PyAudio()
stream = pyaudio_handle.open(
    format=pyaudio.get_format_from_width(2,unsigned=False),
    channels=4,
    rate=48000,
    input=True,
    frames_per_buffer=256,
    input_device_index=32,
    stream_callback=pyaudio_stream_callback,
)

尝试以高于44.1 kHz的速率初始化ASIO驱动程序会导致PyAudio挂起而不返回.初始化为44.1 kHz会产生以下错误：IOError：[Errno Unanticipated host error] -9999.

您可以提供的任何帮助来解决此错误都会有所帮助.我甚至会支持ASIO使用>的证据.在Win7上运行时,PyAudio中有2个通道.谢谢.

解决方法:

我能够在96 kHZ下使用ASIO驱动程序录制8声道音频(M-audio M-Track Eight).

从

p = pyaudio.PyAudio()
p.get_device_info_by_index(4)

我发现’index’：4是ASIO驱动程序：

{'defaultLowInputLatency': 0.005804988662131519, 
 'defaultHighOutputLatency': 0.09287981859410431, 
 'defaultLowOutputLatency': 0.005804988662131519,
 'defaultSampleRate': 44100.0, 
 'maxInputChannels': 8, 
 'maxOutputChannels': 8,
 'structVersion': 2, 
 'name': 'M-Audio M-Track Eight ASIO', 
 'index': 4, 
 'hostApi': 2,
 'defaultHighInputLatency': 0.09287981859410431}

所以我从PyAudio开始使用示例代码,但是从wave切换到scipy.io.wav文件以写入多声道.wav文件,因为wave只支持立体声.

import pyaudio
import wave
import numpy as np
from scipy.io import wavefile

CHUNK = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 8
RATE = 96000
RECORD_SECONDS = 10
WAVE_OUTPUT_FILENAME = "output.wav"

p = pyaudio.PyAudio()

stream = p.open(format=FORMAT,
                channels=CHANNELS,
                rate=RATE,
                input=True,
                input_device_index=4,
                frames_per_buffer=CHUNK
                )

print("* recording")

frames = []

for i in range(0, int(RATE / CHUNK * RECORD_SECONDS)):
    data = stream.read(CHUNK)
    frames.append(data)

print("* done recording")

stream.stop_stream()
stream.close()
p.terminate()


#Not really sure what b'' means in BYTE STRING but numpy needs it 
#just like wave did...
framesAll = b''.join(frames)

#Use numpy to format data and reshape.  
#PyAudio output from stream.read() is interlaced.
result = np.fromstring(framesAll, dtype=np.int16)
chunk_length = len(result) / CHANNELS
result = np.reshape(result, (chunk_length, CHANNELS))

#Write multi-channel .wav file with SciPy
wavfile.write(WAVE_OUTPUT_FILENAME,RATE,result)

中提琴！ 96 kHz,16位,8通道.wav文件！

哦,细节

> Win7 64bit
> M-Audio Eight 64位Windows驱动程序1.0.11
> Python 3.4.2 32位
> PyAudio 0.2.8 for Win7 from
here
> numpy-1.9.2
> scipy-0.15.1-win32-superpack-python3.4

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