将Win10音频网络Python脚本移植到Ubuntu遇ALSA/JACK问题求助

我编写了一套Python程序，分为Client和Receiver两部分，功能是捕获麦克风输入并通过私有网络传输至另一台机器，再映射到该机器的扬声器播放。这套程序在Windows 10机器间运行正常，但在Ubuntu 22.04 LTS + Ubuntu Studio插件的VirtualBox虚拟机（桥接网络，已授权主机音频访问）中作为发送端测试时，出现大量ALSA和JACK相关错误，安装Ubuntu Studio的ALSA和JACK驱动后问题依旧。

启动脚本的错误输出如下：

ALSA lib pcm_dmix.c:1032:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround71
ALSA lib setup.c:547:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
ALSA lib pcm.c:2664:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
ALSA lib confmisc.c:160:(snd_config_get_card) Invalid field card
ALSA lib pcm_usb_stream.c:482:(_snd_pcm_usb_stream_open) Invalid card 'card'
ALSA lib confmisc.c:160:(snd_config_get_card) Invalid field card
ALSA lib pcm_usb_stream.c:482:(_snd_pcm_usb_stream_open) Invalid card 'card'
ALSA lib pcm_dmix.c:1032:(snd_pcm_dmix_open) unable to open slave
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
/home/ben/Desktop/reciever.py:42: DeprecationWarning: setDaemon() is deprecated, set the daemon attribute instead
  udpThread .setDaemon(True)
/home/ben/Desktop/reciever.py:43: DeprecationWarning: setDaemon() is deprecated, set the daemon attribute instead
  AudioThread.setDaemon(True)
^[[1;2D^CTraceback (most recent call last):
  File "/home/ben/Desktop/reciever.py", line 46, in <module>
    udpThread .join()
  File "/usr/lib/python3.10/threading.py", line 1096, in join
    self._wait_for_tstate_lock()
  File "/usr/lib/python3.10/threading.py", line 1116, in _wait_for_tstate_lock
    if lock.acquire(block, timeout):
KeyboardInterrupt

1. 优先解决JACK服务启动失败问题 #

从错误日志看，JACK服务无法启动是核心阻塞点，Python音频库大概率在尝试连接JACK但失败，进而触发后续ALSA错误。

解决步骤： #

• 配置JACK权限：
  将当前用户添加到音频相关用户组，确保权限足够：

  sudo usermod -aG audio $USER
  sudo usermod -aG jackuser $USER
  

  注销后重新登录生效。

• 手动启动JACK并排查错误：
  终端执行jackd -d alsa，查看具体启动报错。常见问题及处理：

  • VirtualBox音频控制器设置：进入虚拟机设置，将音频控制器改为Intel HD Audio，并确认"启用音频输入"已勾选。
  • 指定正确音频设备启动：先执行arecord -l查看系统识别到的麦克风设备，再用对应设备编号启动JACK：

    jackd -d alsa -d hw:0
    

    其中hw:0替换为arecord -l输出中的实际设备编号。

• 用QjackCtl图形化调试：
  打开Ubuntu Studio自带的QjackCtl，在"设置"中选择正确的音频设备，点击"启动"后查看日志面板的详细错误，针对性调整采样率（VirtualBox建议44100Hz）、缓冲区大小（建议1024）等参数。

2. 修复ALSA无效设备配置 #

日志中Unknown PCM错误是系统尝试加载不存在的音频设备（如HDMI、后置音箱等）导致，可通过配置屏蔽这些无效项：

• 编辑~/.asoundrc（用户级配置）或/etc/asound.conf（系统级配置），添加以下内容：

  pcm.!default {
      type hw
      card 0
  }
  ctl.!default {
      type hw
      card 0
  }
  

  其中card 0替换为aplay -l输出中的主音频设备编号，保存后重启ALSA服务：

  sudo alsa force-reload
  

3. 强制Python音频库使用ALSA后端 #

如果JACK配置仍有问题，可强制Python音频库跳过JACK直接使用ALSA：

• 以pyaudio为例，初始化时指定正确设备：

  import pyaudio
  p = pyaudio.PyAudio()
  # 列出所有可用设备，找到麦克风对应的编号
  for i in range(p.get_device_count()):
      print(p.get_device_info_by_index(i))
  # 用正确设备初始化输入流
  stream = p.open(format=pyaudio.paInt16,
                  channels=1,
                  rate=44100,
                  input=True,
                  input_device_index=0) # 替换为实际麦克风设备编号
  

• 对于sounddevice库，设置环境变量强制使用ALSA：

  import os
  os.environ['SOUNDDEVICE_BACKEND'] = 'alsa'
  import sounddevice as sd
  

4. 修复代码中的废弃API警告 #

将代码中的setDaemon()替换为daemon属性：

udpThread.daemon = True
AudioThread.daemon = True

内容的提问来源于stack exchange，提问作者Bencosterton