ALSA&Python捕捉多个单声道音频输入

Question

我正在使用python音频alsa库与我的m-audio Delta 1010LT PCI音频接口交互。这个音频接口有8个模拟输入。我想分析一个特定的单声道输入信号。正在识别卡：

cat /proc/asound/cards 0 [M1010LT        ]: ICE1712 - M Audio Delta 1010LT
                  M Audio Delta 1010LT at 0xa000, irq 18

之后，我用命令“amixer”列出了所有设备名（在这里显示输入adc）

^{pr2}$

之后，我用命令“arecord-l”列出了录制硬件设备

arecord -l**** List of CAPTURE Hardware Devices ****
card 0: M1010LT [M Audio Delta 1010LT], device 0: ICE1712 multi [ICE1712 multi]
Subdevices: 1/1
Subdevice #0: subdevice #0

我说得对吗？这只显示一个录音子设备吗？不应该是8点吗？在

我还安装了Mudita24-一个envy24可视化混音器。有了这个，我可以完美地调整和监控所有输入通道的电平。在

之后，我用GStreamer做了一个小测试，效果也很好：

gst-launch-0.10 alsasrc card-name=0 device-name='ADC 0' ! queue ! alsasink card-name=0 device-name='DAC 0'

但是我在使用以下卡和设备描述符来处理python的alsa中的某个单通道时遇到了困难：

'default'  // This one get's me channel 1 & 2 MIXED (I'd like to get them as seperated mono inputs)
'hw:0,0'   // recognizes device but the input value is 0
'hw:0,0,0' // returns same as hw:0,0
'hw:0,0,1' // Device or resource busy (pretty much every other value than 0 returns this)
'hw:0,1'   // No such file or directory

如何使用ALSA寻址特定的单声道输入通道？这是我使用的python库：link

这就是我尝试为每个频道创建设备的方法：

pcm.one_channel {
@args [ CHANNEL ]
@args.CHANNEL { type integer }
type dsnoop
ipc_key 20130206
slave {
    pcm "hw:0"
    channels 12
    rate 44000
}
bindings [ $CHANNEL ]
}

pcm.two_channel {
    @args [ CHANNEL ]
    @args.CHANNEL { type integer }
    type dsnoop
    ipc_key 20130206
    slave {
        pcm "hw:0"
        channels 12
        rate 44000
    }
    bindings [ $CHANNEL ]
}

pcm.three_channel {
    @args [ CHANNEL ]
    @args.CHANNEL { type integer }
    type dsnoop
    ipc_key 20130206
    slave {
        pcm "hw:0"
        channels 12
        rate 44000
    }
    bindings [ $CHANNEL ]
}

pcm.four_channel {
    @args [ CHANNEL ]
    @args.CHANNEL { type integer }
    type dsnoop
    ipc_key 20130206
    slave {
        pcm "hw:0"
        channels 12
        rate 44000
    }
    bindings [ $CHANNEL ]
}

pcm.five_channel {
    @args [ CHANNEL ]
    @args.CHANNEL { type integer }
    type dsnoop
    ipc_key 20130206
    slave {
        pcm "hw:0"
        channels 12
        rate 44000
    }
    bindings [ $CHANNEL ]
}

我正确地解释了你的建议吗？我也在网上找了这张卡，找到了另外两张.asoundrc（不幸的是，这张卡也不起作用）。在

#
# M-Audio Delta 1010
#

pcm.ice1712_capture {
    type dsnoop
    ipc_key 1024
    slave {
        pcm "hw:0"
        period_size 0
        buffer_size 65536
        rate 44100
        channels 10
        format "S16_LE"
    }
}

pcm.ice1712_playback {
    type dsnoop
    ipc_key 1024
    slave {
        pcm "hw:0"
        period_size 0
        buffer_size 65536
        rate 44100
        channels 10
        format "S16_LE"
    }
}

pcm.ice1712_duplex {
    type asym
    playback.pcm ice1712_playback
    capture.pcm ice1712_capture
}

pcm.ch1 {
    type plug
    ttable.0.0 1
    slave.pcm ice1712_duplex
}

pcm.ch2 {
    type plug
    ttable.1.1 1
    slave.pcm ice1712_duplex
}

pcm.ch3 {
    type plug
    ttable.0.2 1
    slave.pcm ice1712_duplex
}

pcm.ch4 {
    type plug
    ttable.1.3 1
    slave.pcm ice1712_duplex
}

pcm.ice1712_ch5 {
    type plug
    ttable.0.4 1
    slave.pcm ice1712_duplex
}

pcm.ice1712_ch6 {
    type plug
    ttable.1.5 1
    slave.pcm ice1712_duplex
}

pcm.ice1712_ch7 {
    type plug
    ttable.0.6 1
    slave.pcm ice1712_duplex
}

pcm.ice1712_ch8 {
    type plug
    ttable.1.7 1
    slave.pcm ice1712_duplex
}

pcm.ice1712_ch9 {
    type plug
    ttable.0.8 1
    slave.pcm ice1712_duplex
}

pcm.ice1712_ch10 {
    type plug
    ttable.1.9 1
    slave.pcm ice1712_duplex
}

还有一个：

pcm.multi_capture {
    type multi
    slaves.a.pcm hw:0 
    slaves.a.channels 12

# First 8 channels of first soundcard (capture)
    bindings.0.slave a
    bindings.0.channel 0
    bindings.1.slave a
    bindings.1.channel 1
    bindings.2.slave a
    bindings.2.channel 2
    bindings.3.slave a
    bindings.3.channel 3
    bindings.4.slave a
    bindings.4.channel 4
    bindings.5.slave a
    bindings.5.channel 5
    bindings.6.slave a
    bindings.6.channel 6
    bindings.7.slave a
    bindings.7.channel 7

# S/PDIF section. Uncomment bindings if required.

# S/PDIF first soundcard (capture)
    #bindings.16.slave a
    #bindings.16.channel 8
    #bindings.17.slave a
    #bindings.17.channel 9
}

ctl.multi_capture {
    type hw
    card 0
}

pcm.multi_playback {
    type multi
    slaves.a.pcm hw:0
    slaves.a.channels 10

# First 8 channels of first soundcard (playback)
    bindings.0.slave a
    bindings.0.channel 0
    bindings.1.slave a
    bindings.1.channel 1
    bindings.2.slave a
    bindings.2.channel 2
    bindings.3.slave a
    bindings.3.channel 3
    bindings.4.slave a
    bindings.4.channel 4
    bindings.5.slave a
    bindings.5.channel 5
    bindings.6.slave a
    bindings.6.channel 6
    bindings.7.slave a
    bindings.7.channel 7

# S/PDIF section. Uncomment bindings if required.

# S/PDIF first soundcard (playback)
    #bindings.16.slave a
    #bindings.16.channel 8
    #bindings.17.slave a
    #bindings.17.channel 9
}

ctl.multi_playback {
    type hw
    card 0
}

Answer 1

amixer工具不显示设备名称，但显示混音器控件。在

ICE1712芯片实际上只有一个捕获设备（正好有12个通道）。在

---

要为各个频道获取虚拟设备，请尝试向您的~/.asoundrc或/etc/asound.conf添加以下内容：

pcm.one_channel {
    @args [ CHANNEL ]
    @args.CHANNEL { type integer }
    type dsnoop
    ipc_key 20130206
    slave {
        pcm "hw:0"
        channels 12
        rate 48000
    }
    bindings [ $CHANNEL ]
}

然后使用设备名，如one_channel:0，one_channel:1，等等