我已经安装了PyAudio，它的工作方式完全符合我的要求，无论是播放还是录制音频。然而，每次初始化PyAudio对象时，它都会在STDERR中弹出一大堆警告和错误，这使得我很难对自己的应用程序日志进行排序。以下是ipython会话的示例：
In [1]: from pyaudio import PyAudio
In [2]: PyAudio()
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition 'cards.USB-Audio.pcm.hdmi.0:CARD=0,AES0=4,AES1=130,AES2=0,AES3=2'
ALSA lib conf.c:4745:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5233:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM hdmi
ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition 'cards.USB-Audio.pcm.hdmi.0:CARD=0,AES0=4,AES1=130,AES2=0,AES3=2'
ALSA lib conf.c:4745:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5233:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM hdmi
ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition 'cards.USB-Audio.pcm.modem.0:CARD=0'
ALSA lib conf.c:4745:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5233:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline:CARD=0,DEV=0
ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition 'cards.USB-Audio.pcm.modem.0:CARD=0'
ALSA lib conf.c:4745:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5233:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline:CARD=0,DEV=0
ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition 'cards.USB-Audio.pcm.modem.0:CARD=0'
ALSA lib conf.c:4745:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5233:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM phoneline
ALSA lib confmisc.c:1281:(snd_func_refer) Unable to find definition 'cards.USB-Audio.pcm.modem.0:CARD=0'
ALSA lib conf.c:4745:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5233:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2660:(snd_pcm_open_noupdate) Unknown PCM phoneline
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=No such file or directory)
attempt to connect to server failed
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=No such file or directory)
attempt to connect to server failed
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
connect(2) call to /dev/shm/jack-1000/default/jack_0 failed (err=No such file or directory)
attempt to connect to server failed
Out[2]: <pyaudio.PyAudio at 0x7f7066350850>
我翻遍了源代码，找不到它从哪里冒出来，据我所知，这不是通过Python的logging功能发生的，因为它打印[]:
import logging
print([logging.getLogger(name) for name in logging.root.manager.loggerDict])
它似乎没有告诉我任何我需要知道的事情，所以我希望它只是。。。停止如有任何帮助，我们将不胜感激。
问题是PyAudio在任何时候都会加载一堆非Python的东西，而正是这些东西正在打印到STDOUT，所以它必须直接静音。做到这一点最干净的方法是将其封装在上下文管理器中，使STDOUT在尽可能短的时间内静音：
import os
from pyaudio import PyAudio
class pyaudio:
"""
PyAudio is noisy af every time you initialise it, which makes reading the
log output rather difficult. The output appears to be being made by the
C internals, so I can't even redirect the logs with Python's logging
facility. Therefore the nuclear option was selected: swallow all stderr
and stdout for the duration of PyAudio's use.
Lifted and adapted from StackOverflow:
https://stackoverflow.com/questions/11130156/
"""
def __init__(self):
# Open a pair of null files
self.null_fds = [os.open(os.devnull, os.O_RDWR) for x in range(2)]
# Save the actual stdout (1) and stderr (2) file descriptors.
self.save_fds = [os.dup(1), os.dup(2)]
self.pyaudio = None
def __enter__(self) -> PyAudio:
# Assign the null pointers to stdout and stderr.
os.dup2(self.null_fds[0], 1)
os.dup2(self.null_fds[1], 2)
self.pyaudio = PyAudio()
return self.pyaudio
def __exit__(self, *_):
self.pyaudio.terminate()
# Re-assign the real stdout/stderr back to (1) and (2)
os.dup2(self.save_fds[0], 1)
os.dup2(self.save_fds[1], 2)
# Close all file descriptors
for fd in self.null_fds + self.save_fds:
os.close(fd)
使用上面看起来像这样：
with pyaudio() as audio:
...