除了“默认”之外，我应该在 snd_pcm_open 中给出什么设备名称

Question

我想同时从 2 个设备录制声音：

• 内置麦克风
• 外置 USB 网络摄像头麦克风

使用pulseaudio声音控制器，我将这些设备中的任何一个设置为默认值，并且可以使用snd_pcm_open(&handle, "default", SND_PCM_STREAM_CAPTURE, 0).

但是现在我想同时从两个设备录制声音，所以我必须选择这里提到的命名方案。但是，我对其中的几个都没有成功。

我认为这会解决我的问题，但front:CARD=U0x46d0x825,DEV=0作为设备名称并没有帮助。

我收到这些错误：

ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM
ALSA lib pcm_hw.c:1667:(_snd_pcm_hw_open) Invalid value for card

arecord -l 给我：

# arecord -l
**** List of CAPTURE Hardware Devices ****
Home directory not accessible: Permission denied
card 0: PCH [HDA Intel PCH], device 0: ALC662 rev1 Analog [ALC662 rev1 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 2: ALC662 rev1 Alt Analog [ALC662 rev1 Alt Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: U0x46d0x825 [USB Device 0x46d:0x825], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

并# arecord -L给出：

# arecord -L
null
    Discard all samples (playback) or generate zero samples (capture)
pulse
    PulseAudio Sound Server
default:CARD=PCH
    HDA Intel PCH, ALC662 rev1 Analog
    Default Audio Device
sysdefault:CARD=PCH
    HDA Intel PCH, ALC662 rev1 Analog
    Default Audio Device
front:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    Front speakers
surround40:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
dmix:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    Direct sample mixing device
dmix:CARD=PCH,DEV=2
    HDA Intel PCH, ALC662 rev1 Alt Analog
    Direct sample mixing device
dsnoop:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    Direct sample snooping device
dsnoop:CARD=PCH,DEV=2
    HDA Intel PCH, ALC662 rev1 Alt Analog
    Direct sample snooping device
hw:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    Direct hardware device without any conversions
hw:CARD=PCH,DEV=2
    HDA Intel PCH, ALC662 rev1 Alt Analog
    Direct hardware device without any conversions
plughw:CARD=PCH,DEV=0
    HDA Intel PCH, ALC662 rev1 Analog
    Hardware device with all software conversions
plughw:CARD=PCH,DEV=2
    HDA Intel PCH, ALC662 rev1 Alt Analog
    Hardware device with all software conversions
default:CARD=U0x46d0x825
    USB Device 0x46d:0x825, USB Audio
    Default Audio Device
sysdefault:CARD=U0x46d0x825
    USB Device 0x46d:0x825, USB Audio
    Default Audio Device
front:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    Front speakers
surround40:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    Direct sample mixing device
dsnoop:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    Direct sample snooping device
hw:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    Direct hardware device without any conversions
plughw:CARD=U0x46d0x825,DEV=0
    USB Device 0x46d:0x825, USB Audio
    Hardware device with all software conversions

那么，根据 ALSA 规范，我应该为上述设备提供哪些正确名称以同时记录它们？

我不希望使用pulseaudioAPI。

Answer 1

尝试跑步

$ cat /proc/asound/devices
  1:        : sequencer
  2: [ 0- 3]: digital audio playback
  3: [ 0- 0]: digital audio playback
  4: [ 0- 0]: digital audio capture
  5: [ 0- 3]: hardware dependent
  6: [ 0- 0]: hardware dependent
  7: [ 0]   : control
 33:        : timer

使用设备号不为零的第一个音频设备