运行portaudio示例时Ubuntu出错

Question

我在Ubuntu 14.04上安装了portaudio，并编译了测试程序，如下所示：

gcc -o Test3c Test3c.c ../libportaudio.a -lrt -lasound -ljack -lpthread -lm

没有错误。(Test3c.c与here中包含的pa_devs.c相同。)但当我运行它时，

./Test3c

我明白了：

ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
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
PortAudio version number = 1899
PortAudio version text = 'PortAudio V19-devel (built Feb 14 2015 11:51:22)'
Number of devices = 20
--------------------------------------- device #0
Name                        = HDA Intel PCH: ALC892 Analog (hw:0,0)
Host API                    = ALSA
Max inputs = 2, Max outputs = 6
Default low input latency   =   0.0058
Default low output latency  =   0.0087
Default high input latency  =   0.0348
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 2 channel input = 
    44100.00, 48000.00, 96000.00, 192000.00
Supported standard sample rates
 for half-duplex 16 bit 6 channel output = 
None
Supported standard sample rates
 for full-duplex 16 bit 2 channel input, 6 channel output = 
None
--------------------------------------- device #1
Name                        = HDA Intel PCH: ALC892 Digital (hw:0,1)
Host API                    = ALSA
Max inputs = 0, Max outputs = 2
Default low input latency   =  -1.0000
Default low output latency  =   0.0058
Default high input latency  =  -1.0000
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 2 channel output = 
    32000.00, 44100.00, 48000.00, 88200.00,
    96000.00, 192000.00
--------------------------------------- device #2
Name                        = HDA Intel PCH: ALC892 Alt Analog (hw:0,2)
Host API                    = ALSA
Max inputs = 2, Max outputs = 0
Default low input latency   =   0.0058
Default low output latency  =  -1.0000
Default high input latency  =   0.0348
Default high output latency =  -1.0000
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 2 channel input = 
    44100.00, 48000.00, 96000.00, 192000.00
--------------------------------------- device #3
Name                        = HDA NVidia: HDMI 0 (hw:1,3)
Host API                    = ALSA
Max inputs = 0, Max outputs = 8
Default low input latency   =  -1.0000
Default low output latency  =   0.0058
Default high input latency  =  -1.0000
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 8 channel output = 
    32000.00, 44100.00, 48000.00, 88200.00,
    96000.00, 192000.00
--------------------------------------- device #4
Name                        = HDA NVidia: HDMI 0 (hw:1,7)
Host API                    = ALSA
Max inputs = 0, Max outputs = 8
Default low input latency   =  -1.0000
Default low output latency  =   0.0058
Default high input latency  =  -1.0000
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 8 channel output = 
    32000.00, 44100.00, 48000.00, 88200.00,
    96000.00, 192000.00
--------------------------------------- device #5
Name                        = HDA NVidia: HDMI 0 (hw:1,8)
Host API                    = ALSA
Max inputs = 0, Max outputs = 8
Default low input latency   =  -1.0000
Default low output latency  =   0.0058
Default high input latency  =  -1.0000
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 8 channel output = 
    32000.00, 44100.00, 48000.00, 88200.00,
    96000.00, 192000.00
--------------------------------------- device #6
Name                        = HDA NVidia: HDMI 0 (hw:1,9)
Host API                    = ALSA
Max inputs = 0, Max outputs = 8
Default low input latency   =  -1.0000
Default low output latency  =   0.0058
Default high input latency  =  -1.0000
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 8 channel output = 
    32000.00, 44100.00, 48000.00, 88200.00,
    96000.00, 192000.00
--------------------------------------- device #7
Name                        = sysdefault
Host API                    = ALSA
Max inputs = 128, Max outputs = 128
Default low input latency   =   0.0213
Default low output latency  =   0.0213
Default high input latency  =   0.0213
Default high output latency =   0.0213
Default sample rate         = 48000.00
Supported standard sample rates
 for half-duplex 16 bit 128 channel input = 
     8000.00,  9600.00, 11025.00, 16000.00,
    22050.00, 32000.00, 44100.00, 48000.00,
    88200.00
Supported standard sample rates
 for half-duplex 16 bit 128 channel output = 
     8000.00,  9600.00, 11025.00, 16000.00,
    22050.00, 32000.00, 44100.00, 48000.00,
    88200.00
Supported standard sample rates
 for full-duplex 16 bit 128 channel input, 128 channel output = 
     8000.00,  9600.00, 11025.00, 16000.00,
    22050.00, 32000.00, 44100.00, 48000.00,
    88200.00
--------------------------------------- device #8
Name                        = front
Host API                    = ALSA
Max inputs = 0, Max outputs = 6
Default low input latency   =  -1.0000
Default low output latency  =   0.0058
Default high input latency  =  -1.0000
Default high output latency =   0.0348
Default sample rate         = 44100.00
Supported standard sample rates
 for half-duplex 16 bit 6 channel output = 
Test3c: pcm_params.c:2249: snd1_pcm_hw_params_slave: Assertion `err >= 0' failed.
Aborted (core dumped)

Answer 1

所以我想我找到了一个解决方案。在最近的错误之后，我注意到建议使用不同的音频问题here以以下方式重新启动音频驱动程序：

pulseaudio -k && sudo alsa force-reload

我这样做了，然后尝试运行编译后的程序，但再次遇到错误(我想我有点不耐烦了)。然后，我再次执行此命令，现在它可以工作了。

更新:过了一段时间，我又收到了这个错误，必须重新启动驱动程序。

Answer 2

目前我是Portaudio-linux主机的维护人员，在这里刚刚遇到了这个问题。Portaudio邮件列表上也报告了同样的问题，并对此进行了调查。断言在Alsa-lib中，现在已被Alsa开发人员删除，以支持错误返回。看见

http://git.alsa-project.org/?p=alsa-lib.git;a=commit;h=67f73b0fab466e780dcc0442e19894a1cbedc43b

某些设备似乎在“正面”(和其他一些)PCM上造成了6通道的问题。这不是Portaudio的错误，但当它探测设备和PCM的功能时，它暴露了Alsa系统中的问题。删除断言后，它现在只是无法实现这些功能。

Answer 3

我遇到了同样的问题，并通过修复/usr/share/alsa/pcm中的一些错误的pcm定义解决了它。在靠近文件底部的route部分中，卡驱动程序引用的pcm与文件中定义的pcm不同。