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ALSA与Python - 捕获多个单声道音频输入

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1 回答
3918 浏览
提问于 2025-04-17 14:56

我正在使用Python的alsa音频库来和我的M-Audio Delta 1010LT PCI音频接口进行交互。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。系统已经识别到这个声卡：

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

之后，我用“amixer”这个命令列出了所有设备名称（这里显示的是输入的ADC）。

...
Simple mixer control 'ADC',0
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 142 [87%] [7.50dB]
Simple mixer control 'ADC',1
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
Simple mixer control 'ADC',2
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
Simple mixer control 'ADC',3
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
Simple mixer control 'ADC',4
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
Simple mixer control 'ADC',5
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
Simple mixer control 'ADC',6
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
Simple mixer control 'ADC',7
Capabilities: volume volume-joined penum
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 164
Mono: 164 [100%] [18.50dB]
...

接着，我用“arecord -l”这个命令列出了录音硬件设备。

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

我这样做对吗？这是不是只显示了一个录音子设备？难道不应该显示8个吗？

我还安装了Mudita24，这是一个envy24的可视化混音器。通过这个软件，我可以完美地调整和监控所有输入通道的音量。

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'

但是我在用Python的alsa时，想要访问某个特定的单声道通道时遇到了问题，使用了以下的卡和设备描述：

'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

我该如何使用ALSA来访问特定的单声道输入通道？这是我正在使用的Python库：链接

这是我尝试为每个通道创建设备的方式：

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 ]
}

我理解你的建议正确吗？我也在网上查找过这个问题，发现了两个其他的.asoundrc文件，但不幸的是它们也不管用。

#
# 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
}
GStreamer alsa adc 混音器 音频接口 单声道输入 录音设备 音量监控

1 个回答

2

amixer这个工具不会显示设备的名字，而是显示混音控制。

ICE1712芯片实际上只有一个录音设备（正好有12个通道）。

如果你想为每个通道创建虚拟设备，可以尝试在你的~/.asoundrc或/etc/asound.conf中添加类似下面的内容：

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

然后你可以使用像one_channel:0、one_channel:1这样的设备名称。

回答于 2025-04-17 由 Python大师
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