A40i/T3
内部集成
Audio Codec
是一款带耳机放大器的高品质立体声音频编解码器。用户可以使用文件系统内带的 ALSA 音频录制、播放、配置工具进行测试。
一、音频系统简单配置
1. ALSA
在 ALSA 的定义里,系统中的每一个音频设备都称作“声卡”。可以使用如下命令列出所有已连接的音频设备:
# cat /proc/asound/cards
0 [audiocodec ]: audiocodec - audiocodec
audiocodec
1 [sndhdmi ]: sndhdmi - sndhdmi
sndhdmi
#
可以看到此时系统中有2个声卡,声卡 0 audiocodec和声卡1 sndhdmi
。
或者通过下面的指令查看当前设备的声卡
# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: audiocodec [audiocodec], device 0: SUNXI-CODEC sun8iw11codec-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: sndhdmi [sndhdmi], device 0: SUNXI-HDMIAUDIO sndhdmi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
#
用amixer scontents查看有哪些参数可以控制(包含所有控制器的音量信息)
# amixer scontents
Simple mixer control 'Headphone',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [on]
Simple mixer control 'Headphone volume',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 63
Mono: 59 [94%]
Simple mixer control 'PCM music volume',0
Capabilities: volume
Playback channels: Front Left - Front Right
Capture channels: Front Left - Front Right
Limits: 0 - 255
Front Left: 255 [100%]
Front Right: 255 [100%]
Simple mixer control 'FM gain volume',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 7
Mono: 3 [43%]
Simple mixer control 'Phone Out Mixer LOMIX',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [on]
Simple mixer control 'Phone Out Mixer MIC1 Boost',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Phone Out Mixer MIC2 Boost',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'Phone Out Mixer ROMIX',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [on]
Simple mixer control 'Phoneout Speaker',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [on]
Simple mixer control 'ADC gain volume',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 7
Mono: 3 [43%]
Simple mixer control 'HPL Mux',0
Capabilities: enum
Items: 'DAC' 'OMIX'
Item0: 'DAC'
Simple mixer con