客户要求实现录音功能，所以采用Pyaudio进行声音流采集
安装和示例请访问:
http://people.csail.mit.edu/hubert/pyaudio/
遇到显示警告问题:
ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.front ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround21 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround21 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround40 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround41 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround50 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround51 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround71 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958 ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline ALSA lib ../../../alsa-lib-1.1.2/src/pcm/pcm_dmix.c:1041:(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
上面一些不影响录音的警报,ALSA部分是没有找到声卡,下面是没有找打jack server。声音采集是OK了不过客户对报警不满意，所以寻找办法清除报警信息。
消除ALSA 报警（博客地址忘了）
/usr/share/alsa/alsa.conf(可能位置有变化)，中配置了声卡信息，那么可以根据上面的报错删除对应的声卡就可以了。
这样就只剩下jack server的信息了。因为Pyaudio 在实例对象时，直接开启了声音采集和播放的功能，所以一直没有办法关掉jack server 的信息。
使用 sys模块去除警报
在代码中使用 os.close(sys.stderr.fileno()) # (记得导入模块) 参考：https://stackoverflow.com/questions/36956083/how-can-the-terminal-output-of-executables-run-by-python-functions-be-silenced-i 这样可以不展示系统的err消息，所以ALSA 和jack server 的消息都不会被展示。
具体的原理和代码示例参照 https://eli.thegreenplace.net/2015/redirecting-all-kinds-of-stdout-in-python/
使用sounddevice 据说也可以解决这个问题(没试过)
