PyAudio工作正常，但每次都会吐出错误消息 [英] PyAudio working, but spits out error messages each time

问题描述

我正在使用PyAudio记录来自麦克风的输入。

I'm using PyAudio to record input from the microphone.

由于音频对我来说很好，我是否应该简单地抑制它的错误消息？还是有解决它们的方法？

Since the audio is recording fine for me, should I try to simply suppress its error messages? Or would there be a way of resolving them?

ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib audio/pcm_bluetooth.c:1613:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5)
ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave
Cannot connect to server socket err = No such file or directory
Cannot connect to server socket
jack server is not running or cannot be started

推荐答案

您可以尝试清理ALSA配置，例如，

You can try to clean up your ALSA configuration, for example,

ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2212:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side

是由 / usr / share / alsa引起的/alsa.conf ：

pcm.rear cards.pcm.rear
pcm.center_lfe cards.pcm.center_lfe
pcm.side cards.pcm.side

一旦发表评论这些行，那些错误信息将消失。您可能还需要检查〜/ .asoundrc 和 /etc/asound.conf 。

Once you comment out these lines, those error message will be gone. You may also want to check ~/.asoundrc and /etc/asound.conf.

这就是说，其中一些消息告诉您配置中有问题，尽管它们不会引起任何实际问题。我不建议您清理 alsa.conf ，因为它最初来自ALSA，在您更新alsa-lib时可能会被覆盖。

That's said, some of those messages are telling something is wrong in your configuration, though they do not cause any real problem. I do not recommend you clean up the alsa.conf, because it's from ALSA originally, it may be overwritten when you update alsa-lib.

有一种在Python中隐藏消息的方法，下面是示例代码：

There is a way to suppress the message in Python, here is a sample code:

#!/usr/bin/env python
from ctypes import *
import pyaudio

# From alsa-lib Git 3fd4ab9be0db7c7430ebd258f2717a976381715d
# $ grep -rn snd_lib_error_handler_t
# include/error.h:59:typedef void (*snd_lib_error_handler_t)(const char *file, int line, const char *function, int err, const char *fmt, ...) /* __attribute__ ((format (printf, 5, 6))) */;
# Define our error handler type
ERROR_HANDLER_FUNC = CFUNCTYPE(None, c_char_p, c_int, c_char_p, c_int, c_char_p)
def py_error_handler(filename, line, function, err, fmt):
  print 'messages are yummy'
c_error_handler = ERROR_HANDLER_FUNC(py_error_handler)

asound = cdll.LoadLibrary('libasound.so')
# Set error handler
asound.snd_lib_error_set_handler(c_error_handler)
# Initialize PyAudio
p = pyaudio.PyAudio()
p.terminate()

print '-'*40
# Reset to default error handler
asound.snd_lib_error_set_handler(None)
# Re-initialize
p = pyaudio.PyAudio()
p.terminate()

我计算机的输出：

messages are yummy
messages are yummy
messages are yummy
messages are yummy
messages are yummy
messages are yummy
----------------------------------------
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1018:(snd_pcm_dmix_open) unable to open slave

这些消息是由alsa-lib打印出来的，不是PyAudio或PortAudio。该代码直接使用alsa-lib snd_lib_error_set_handler 函数设置错误处理程序 py_error_handler ，您可以使用该函数将其删除消息。

Those messages are printed out by alsa-lib, not PyAudio or PortAudio. The code directly uses alsa-lib snd_lib_error_set_handler function to set an error handler py_error_handler, which you can use it to drop any message.

我检查了其他Python ALSA绑定，pyalsa和PyAlsaAudio，它们不支持设置错误处理程序。但是，PortAudio上有一个问题，以前似乎所有ALSA错误消息都已被禁止。

I have checked other Python ALSA bindings, pyalsa and PyAlsaAudio, they do not support setting error handler. However, there is an issue on PortAudio, all ALSA error messages seemed to be suppressed before.

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