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前言

最近在做一个项目，需要使用外放播放声音和麦克风拾取录音，然后还要用到摄像头。采购了一个麦克风和一个USB摄像头。结果部署过程中发现摄像头自带的麦克风被识别为默认麦克风，而且每次开机几乎都是这样，然后专业麦克风必须在声音页面选择才能指定为默认麦克风。

最终实现的需求是交付给客户后可以直接使用，肯定不可能让客户每次开机手动选择一下。

没错，我们的项目就是每天定时拉闸关机，早上拉闸自启动！

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一、pulseaudio 是什么？

PulseAudio is a networked low-latency sound server for Linux, POSIX and Windows systems.

Ubuntu桌面版系统使用的就是pulseaudio ，我们的命令也和这个有关系。

二、配置外放

1.查看所有的外放设备

pacmd list-sinks1 sink(s) available.* index: 1name: <alsa_output.pci-0000_00_1b.0.analog-stereo>driver: <module-alsa-card.c>flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY DYNAMIC_LATENCYstate: SUSPENDEDsuspend cause: IDLEpriority: 9039volume: front-left: 32768 /  50% / -18.06 dB,   front-right: 32768 /  50% / -18.06 dBbalance 0.00base volume: 65536 / 100% / 0.00 dBvolume steps: 65537muted: nocurrent latency: 0.00 msmax request: 0 KiBmax rewind: 0 KiBmonitor source: 1sample spec: s16le 2ch 44100Hzchannel map: front-left,front-rightStereoused by: 0linked by: 0configured latency: 0.00 ms; range is 0.50 .. 2000.00 mscard: 1 <alsa_card.pci-0000_00_1b.0>module: 23properties:alsa.resolution_bits = "16"device.api = "alsa"device.class = "sound"alsa.class = "generic"alsa.subclass = "generic-mix"alsa.name = "CX20751/2 Analog"alsa.id = "CX20751/2 Analog"alsa.subdevice = "0"alsa.subdevice_name = "subdevice #0"alsa.device = "0"alsa.card = "1"alsa.card_name = "HDA Intel PCH"alsa.long_card_name = "HDA Intel PCH at 0xc4314000 irq 50"alsa.driver_name = "snd_hda_intel"device.bus_path = "pci-0000:00:1b.0"sysfs.path = "/devices/pci0000:00/0000:00:1b.0/sound/card1"device.bus = "pci"device.vendor.id = "8086"device.vendor.name = "Intel Corporation"device.product.id = "9ca0"device.product.name = "Wildcat Point-LP High Definition Audio Controller"device.form_factor = "internal"device.string = "front:1"device.buffering.buffer_size = "352800"device.buffering.fragment_size = "176400"device.access_mode = "mmap+timer"device.profile.name = "analog-stereo"device.profile.description = "Analog Stereo"device.description = "Built-in Audio Analog Stereo"module-udev-detect.discovered = "1"device.icon_name = "audio-card-pci"ports:analog-output-speaker: Speakers (priority 10000, latency offset 0 usec, available: unknown)properties:device.icon_name = "audio-speakers"analog-output-headphones: Headphones (priority 9900, latency offset 0 usec, available: no)properties:device.icon_name = "audio-headphones"active port: <analog-output-speaker>

我使用的是笔记本内置外放，也没插额外的外放，所以列表里只有一个。

注意index前面带星号的设备，那就是你当前的选定设备。

2.设定默认的外放设备

设定方法有两个，一是根据index来设定，二是根据name来设定。这里推荐使用name，因为index会变，不是说随时会变，而是每次开机都可能不一样，所以这个方法确认不是好方法。但，也不是说完全不行，只是需要经过稍微复杂点的处理，比如根据awk等工具预处理，找到你想要的那个index再使用，麻烦肯定是麻烦点。

而使用name设定就没有这个问题，前提是你没有改动过驱动等配置。

#必须使用当前登录桌面的用户
pactl set-default-sink <name>
#示例
pactl set-default-sink alsa_output.pci-0000_00_1b.0.analog-stereo

成功shell返回0，失败查看具体提示

3.设定外放设备的声音强度

先看下接受的数据格式：
VOLUME can be specified as an integer (e.g. 2000, 16384), a linear factor
(e.g. 0.4, 1.100), a percentage (e.g. 10%, 100%) or a decibel value (e.g. 0dB,
20dB). If the volume specification start with a + or - the volume adjustment will
be relative to the current sink volume. A single volume value affects all channels;
if multiple volume values are given their number has to match the sink’s number of
channels.

简单翻一下：支持整数，小数，百分比，分贝。这里我选择百分比，没别的原因，因为简单。其他的方式不要滥用，最好带上耳塞，免得震聋耳朵！

#必须使用当前登录桌面的用户
pactl set-sink-volume <外放name> <百分比>
#示例
pactl set-sink-volume alsa_output.pci-0000_00_1b.0.analog-stereo 50%

执行成功shell返回0，失败查看具体提示。

4.设定外放设备静音

理论上声音设置为0%也可以的，但是那不是真正的静音，至少0%音量或许只是声音特别小。

#必须使用当前登录桌面的用户
pactl set-sink-mute <name> 1
#示例
pactl set-sink-mute alsa_output.pci-0000_00_1b.0.analog-stereo 1

仔细看喇叭图标上多了个禁止斜杠。

下面是声音0%，不静音

这下看出差别了吧！

三、配置麦克风

1.查看所有的麦克风设备

#必须使用当前登录桌面的用户
pacmd list-sources2 source(s) available.index: 1name: <alsa_output.pci-0000_00_1b.0.analog-stereo.monitor>driver: <module-alsa-card.c>flags: DECIBEL_VOLUME LATENCY DYNAMIC_LATENCYstate: IDLEsuspend cause: (none)priority: 1030volume: front-left: 65536 / 100% / 0.00 dB,   front-right: 65536 / 100% / 0.00 dBbalance 0.00base volume: 65536 / 100% / 0.00 dBvolume steps: 65537muted: nocurrent latency: 0.00 msmax rewind: 344 KiBsample spec: s16le 2ch 44100Hzchannel map: front-left,front-rightStereoused by: 0linked by: 0configured latency: 2000.00 ms; range is 0.50 .. 2000.00 msmonitor_of: 1card: 1 <alsa_card.pci-0000_00_1b.0>module: 23properties:device.description = "Monitor of Built-in Audio Analog Stereo"device.class = "monitor"alsa.card = "1"alsa.card_name = "HDA Intel PCH"alsa.long_card_name = "HDA Intel PCH at 0xc4314000 irq 50"alsa.driver_name = "snd_hda_intel"device.bus_path = "pci-0000:00:1b.0"sysfs.path = "/devices/pci0000:00/0000:00:1b.0/sound/card1"device.bus = "pci"device.vendor.id = "8086"device.vendor.name = "Intel Corporation"device.product.id = "9ca0"device.product.name = "Wildcat Point-LP High Definition Audio Controller"device.form_factor = "internal"device.string = "1"module-udev-detect.discovered = "1"device.icon_name = "audio-card-pci"* index: 2name: <alsa_input.pci-0000_00_1b.0.analog-stereo>driver: <module-alsa-card.c>flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY DYNAMIC_LATENCYstate: SUSPENDEDsuspend cause: IDLEpriority: 9039volume: front-left: 32768 /  50% / -18.06 dB,   front-right: 32768 /  50% / -18.06 dBbalance 0.00base volume: 13076 /  20% / -42.00 dBvolume steps: 65537muted: nocurrent latency: 0.00 msmax rewind: 0 KiBsample spec: s16le 2ch 44100Hzchannel map: front-left,front-rightStereoused by: 0linked by: 0configured latency: 0.00 ms; range is 0.50 .. 2000.00 mscard: 1 <alsa_card.pci-0000_00_1b.0>module: 23properties:alsa.resolution_bits = "16"device.api = "alsa"device.class = "sound"alsa.class = "generic"alsa.subclass = "generic-mix"alsa.name = "CX20751/2 Analog"alsa.id = "CX20751/2 Analog"alsa.subdevice = "0"alsa.subdevice_name = "subdevice #0"alsa.device = "0"alsa.card = "1"alsa.card_name = "HDA Intel PCH"alsa.long_card_name = "HDA Intel PCH at 0xc4314000 irq 50"alsa.driver_name = "snd_hda_intel"device.bus_path = "pci-0000:00:1b.0"sysfs.path = "/devices/pci0000:00/0000:00:1b.0/sound/card1"device.bus = "pci"device.vendor.id = "8086"device.vendor.name = "Intel Corporation"device.product.id = "9ca0"device.product.name = "Wildcat Point-LP High Definition Audio Controller"device.form_factor = "internal"device.string = "front:1"device.buffering.buffer_size = "352800"device.buffering.fragment_size = "176400"device.access_mode = "mmap+timer"device.profile.name = "analog-stereo"device.profile.description = "Analog Stereo"device.description = "Built-in Audio Analog Stereo"module-udev-detect.discovered = "1"device.icon_name = "audio-card-pci"ports:analog-input-internal-mic: Internal Microphone (priority 8900, latency offset 0 usec, available: unknown)properties:device.icon_name = "audio-input-microphone"analog-input-mic: Microphone (priority 8700, latency offset 0 usec, available: no)properties:device.icon_name = "audio-input-microphone"active port: <analog-input-internal-mic>

2.设置默认麦克风设备

和外放一样不建议使用index，原因就是重启顺序可能会变，还是使用name。

假如你不止插入一个麦克风设备（比如3.5耳机孔+USB麦克风并存）。你只需要记住你需要设置的麦克风设备的名字即可。

我这里是index前面带星号的设备，就是我目前的麦克风设备。

#必须使用当前登录桌面的用户
pactl set-default-sources <name>
#示例
pactl set-default-sources alsa_input.pci-0000_00_1b.0.analog-stereo

执行成功shell返回0，失败查看具体提示。

3.设置麦克风设备声音强度

基本和外放一样，这里直接贴命令了，不赘述了。

多说一句，尽量不要调太高，会出现破音，基本能够满足需要就行了。

#必须使用当前登录桌面的用户
pactl set-source-volume <name> <百分比>
#示例
pactl set-source-volume alsa_input.pci-0000_00_1b.0.analog-stereo 50%

执行成功shell返回0，失败查看具体提示。

4.设置麦克风设备静音

基本和外放一样，这里直接贴命令了，不赘述了。

#必须使用当前登录桌面的用户
pactl set-source-mute <name> 1
#示例
pactl set-source-mute alsa_input.pci-0000_00_1b.0.analog-stereo 1

执行成功shell返回0，失败查看具体提示。

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总结

1、注意不能用root权限，需要你登录desktop的那个用户执行命令
2、linux上搞外设比windows还是差点，你只能指望有声音，不能指望它能带给你什么惊喜，可能是糟心呢。小声告诉你bug不少！
3、有什么疑问的可以留言