PulseAudio 是 Linux 环境下主流的音频服务系统，它介于应用程序和底层音频架构（TinyALSA）之间，负责管理音频流、混合多路音频以及路由到不同的输出设备.

PulseAudio 概述

PulseAudio 是一个跨平台的、可通过网络工作的声音服务，它从一个或多个音源（进程或输入设备）接受声音输入，然后重定向声音到一个或多个槽（声卡，远程网络PulseAudio服务，或其他进程）。它与最底层的ALSA(Advanced Linux Sound Architechture)交互，并为应用程序提供统一的接口，从而实现多路音频混合、音频转发等高级功能。

查看声卡信息

• 在终端中输入下面命令，查看声卡的挂载情况：

root@qcm6490-idp:/opt# cat /proc/asound/cards 0 [qcm6490idpsndca]: qcm6490 - qcm6490-idp-snd-card qcm6490-idp-snd-card 

设备查看与管理

查看可用输出设备(Sinks)

要查看系统当前可用的音频输出设备及其详细信息，可以使用以下命令,
此命令会列出所有可用的sink（输出设备）的索引(index)和名称(name)。输出示例：

 root@qcm6490-idp:/# pactl list short sinks 0 low-latency0 module-pal-card.c s16le 1ch 16000Hz SUSPENDED 1 deep-buffer0 module-pal-card.c s16le 2ch 48000Hz SUSPENDED 2 offload0 module-pal-card.c s16le 2ch 48000Hz SUSPENDED 3 voip-rx0 module-pal-card.c s16le 2ch 48000Hz SUSPENDED 

其中，* 号标记表示当前默认的输出设备。
若要获取更详细的设备信息，请使用：

root@qcm6490-idp:/# pactl list sinks Sink #0 State: SUSPENDED Name: low-latency0 Description: pal sink to play via low-latency path Driver: module-pal-card.c Sample Specification: s16le 1ch 16000Hz Channel Map: mono Owner Module: 1 Mute: no Volume: mono: 65536 / 100% balance 0.00 Base Volume: 65536 / 100% Monitor Source: low-latency0.monitor Latency: 0 usec, configured 0 usec Flags: HARDWARE HW_VOLUME_CTRL LATENCY Properties: device.string = "low_latency" device.description = "pal sink to play via low-latency path" device.icon_name = "audio-card" Ports: speaker: speaker (type: Unknown, priority: 200, available) headset: headset (type: Unknown, priority: 100, available) Active Port: speaker Formats: pcm Sink #1 State: SUSPENDED Name: deep-buffer0 Description: pal sink to play via deep buffer path Driver: module-pal-card.c Sample Specification: s16le 2ch 48000Hz Channel Map: front-left,front-right Owner Module: 1 Mute: no Volume: front-left: 65536 / 100%, front-right: 65536 / 100% balance 0.00 Base Volume: 65536 / 100% Monitor Source: deep-buffer0.monitor Latency: 0 usec, configured 0 usec Flags: HARDWARE HW_VOLUME_CTRL LATENCY Properties: device.string = "deep_buffer" device.description = "pal sink to play via deep buffer path" device.icon_name = "audio-card" Ports: speaker: speaker (type: Unknown, priority: 200, available) headset: headset (type: Unknown, priority: 100, available) bta2dp-out: BT a2dp source port (type: Unknown, priority: 50, not available) Active Port: speaker Formats: pcm Sink #2 State: SUSPENDED Name: offload0 Description: pal sink to play compressed via offload path Driver: module-pal-card.c Sample Specification: s16le 2ch 48000Hz Channel Map: front-left,front-right Owner Module: 1 Mute: no Volume: front-left: 65536 / 100%, front-right: 65536 / 100% balance 0.00 Base Volume: 65536 / 100% Monitor Source: offload0.monitor Latency: 0 usec, configured 0 usec Flags: HARDWARE HW_VOLUME_CTRL LATENCY Properties: device.string = "offload" device.description = "pal sink to play compressed via offload path" device.icon_name = "audio-card" Ports: speaker: speaker (type: Unknown, priority: 200, available) headset: headset (type: Unknown, priority: 100, available) bta2dp-out: BT a2dp source port (type: Unknown, priority: 50, not available) Active Port: speaker Formats: mpeg aac Sink #3 State: SUSPENDED Name: voip-rx0 Description: pal sink to play via voip rx path Driver: module-pal-card.c Sample Specification: s16le 2ch 48000Hz Channel Map: front-left,front-right Owner Module: 1 Mute: no Volume: front-left: 65536 / 100%, front-right: 65536 / 100% balance 0.00 Base Volume: 65536 / 100% Monitor Source: voip-rx0.monitor Latency: 0 usec, configured 0 usec Flags: HARDWARE HW_VOLUME_CTRL LATENCY Properties: device.string = "voip_rx" device.description = "pal sink to play via voip rx path" device.icon_name = "audio-card" Ports: speaker: speaker (type: Unknown, priority: 200, available) headset: headset (type: Unknown, priority: 100, available) btsco-out: BT SCO sink port (type: Unknown, priority: 50, not available) Active Port: speaker Formats: pcm 

查看输入设备(Sources)

类似地，可以查看音频输入设备（如麦克风）：

 root@qcm6490-idp:/# pactl list short sources 0 low-latency0.monitor module-pal-card.c s16le 1ch 16000Hz SUSPENDED 1 deep-buffer0.monitor module-pal-card.c s16le 2ch 48000Hz SUSPENDED 2 offload0.monitor module-pal-card.c s16le 2ch 48000Hz SUSPENDED 3 voip-rx0.monitor module-pal-card.c s16le 2ch 48000Hz SUSPENDED 4 regular0 module-pal-card.c s16le 2ch 48000Hz SUSPENDED 5 regular2 module-pal-card.c s16le 2ch 48000Hz SUSPENDED 6 voip-tx0 module-pal-card.c s16le 1ch 48000Hz SUSPENDED 

录音

板载DIMC录音

root@qcm6490-idp:~# pactl set-source-port 5 speaker-mic root@qcm6490-idp:~# parec -d 5 --file-format=wav output.wav 

3.5mm 耳机录音

使用 3.5mm 耳机录制前需将 gpio8 和 gpio68 电平置高。

root@qcm6490-idp:/opt# rgpiod & root@qcm6490-idp:/opt# sleep 1 root@qcm6490-idp:/opt# rgs c 999 go 4 root@qcm6490-idp:/opt# rgs c 999 gso 0 8 root@qcm6490-idp:/opt# rgs c 999 gw 0 8 1 root@qcm6490-idp:/opt# rgs c 999 gso 0 68 root@qcm6490-idp:/opt# rgs c 999 gw 0 68 1 

• gpio8------------耳机国标/美标切换控制开关，置0：欧标，置1：美标
• gpio68-----------耳机电源供电使能开关，置0:禁用，置1：使能

root@qcm6490-idp:~# pactl set-source-port 5 headset-mic root@qcm6490-idp:~# parec -d 5 --file-format=wav output1.wav 

播放

喇叭播放

// GPIO控制PA的使能开关

rgpiod & sleep 1 rgs c 999 go 4 rgs c 999 gso 0 142 rgs c 999 gw 0 142 1 

root@qcm6490-idp:~# pactl set-sink-port 0 speaker root@qcm6490-idp:~# paplay output.wav 

3.5mm耳机播放

root@qcm6490-idp:~# pactl set-sink-port 0 headset root@qcm6490-idp:~# paplay output1.wav 

Audio 测试

MIPI 屏测试