几天在嵌入式linux上用到alsa command，网上查的资料多不给力，只有动手一点点查，终于可以用了，将这个使用方法告诉大家，以免大家少走弯路。

0.先查看系统支持哪几个alsa cmd:

ll /system/bin/asla*

经查，我的android4.4.2+linux3.10  的系统支持如下 alsa cmd

-rwxr-xr-x root     shell       68242 2014-10-08 05:18 alsa_amixer

-rwxr-xr-x root     shell       67639 2014-10-08 05:18 alsa_aplay

-rwxr-xr-x root     shell      130323 2014-10-08 05:18 alsa_ctl

不同的系统可以稍有不同，比如有的系统就叫aplay\amixer .....

1.如何使用alsa_aplay:

alsa_aplay -h //看一下目前支持哪些用法

-h, --help              help

--version           print current version

-l, --list-devices      list all soundcards and digital audio devices

-L, --list-pcms         list device names

-D, --device=NAME       select PCM by name

-q, --quiet             quiet mode

-t, --file-type TYPE    file type (voc, wav, raw or au)

-c, --channels=#        channels

-f, --format=FORMAT     sample format (case insensitive)

-r, --rate=#            sample rate

-d, --duration=#        interrupt after # seconds

-M, --mmap              mmap stream

-N, --nonblock          nonblocking mode

-F, --period-time=#     distance between interrupts is # microseconds

-B, --buffer-time=#     buffer duration is # microseconds

--period-size=#     distance between interrupts is # frames

--buffer-size=#     buffer duration is # frames

-A, --avail-min=#       min available space for wakeup is # microseconds

-R, --start-delay=#     delay for automatic PCM start is # microseconds

(relative to buffer size if <= 0)

-T, --stop-delay=#      delay for automatic PCM stop is # microseconds from xrun

-v, --verbose           show PCM structure and setup (accumulative)

-V, --vumeter=TYPE      enable VU meter (TYPE: mono or stereo)

-I, --separate-channels one file for each channel

--disable-resample  disable automatic rate resample

--disable-channels  disable automatic channel conversions

--disable-format    disable automatic format conversions

--disable-softvol   disable software volume control (softvol)

--test-position     test ring buffer position

--test-coef=#        test coeficient for ring buffer position (default 8)

expression for validation is: coef * (buffer_size / 2)

--test-nowait       do not wait for ring buffer - eats whole CPU

--max-file-time=#   start another output file when the old file has recorded

for this many seconds

--process-id-file   write the process ID here

--use-strftime      apply the strftime facility to the output file name

会有详细的help说明，这个就不说了，可以自己试。

alsa_aplay -l //列出系统有几个声卡(card 0/1/2....), 及每个卡的一个设备(device 0/1/2....)

比如我的系统为：

**** List of PLAYBACK Hardware Devices ****

card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]

Subdevices: 8/8

Subdevice #0: subdevice #0

Subdevice #1: subdevice #1

Subdevice #2: subdevice #2

Subdevice #3: subdevice #3

Subdevice #4: subdevice #4

Subdevice #5: subdevice #5

Subdevice #6: subdevice #6

Subdevice #7: subdevice #7

card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]

Subdevices: 8/8

Subdevice #0: subdevice #0

Subdevice #1: subdevice #1

Subdevice #2: subdevice #2

Subdevice #3: subdevice #3

Subdevice #4: subdevice #4

Subdevice #5: subdevice #5

Subdevice #6: subdevice #6

Subdevice #7: subdevice #7

card 1: IntelALSASSP [IntelALSASSP], device 0: BT_DEVICE [IntelALSASSP]

Subdevices: 1/1

Subdevice #0: subdevice #0

card 1: IntelALSASSP [IntelALSASSP], device 2: BUILTIN_DEVICE [IntelALSASSP]

Subdevices: 1/1

Subdevice #0: subdevice #0

card 2: cloverviewaudio [cloverview_audio], device 0: 4 []

Subdevices: 2/2

Subdevice #0: subdevice #0

Subdevice #1: subdevice #1

card 2: cloverviewaudio [cloverview_audio], device 1: Voice rt5640-aif2-1 []

Subdevices: 1/1

Subdevice #0: subdevice #0

card 2: cloverviewaudio [cloverview_audio], device 3: BTSCO snd-soc-dummy-dai-3 []

Subdevices: 1/1

Subdevice #0: subdevice #0

card 2: cloverviewaudio [cloverview_audio], device 4: VOIP rt5640-aif2-4 []

Subdevices: 1/1

Subdevice #0: subdevice #0

card 2: cloverviewaudio [cloverview_audio], device 5: IFX_MODEM_MIXING snd-soc-dummy-dai-5 []

Subdevices: 1/1

Subdevice #0: subdevice #0

card 2: cloverviewaudio [cloverview_audio], device 6: virtual-stream rt5640-aif1-6 []

Subdevices: 1/1

Subdevice #0: subdevice #0

card 2: cloverviewaudio [cloverview_audio], device 7: CTP Probe snd-soc-dummy-dai-7 []

Subdevices: 1/1

Subdevice #0: subdevice #0

由于我的codec 为alc5640,所以

从上面得知alc5640挂在card2上，所以以后我们当配置amixer 5640时就-c 2 就对了。

2. alsa_amixer的用法

alsa_amixer -h //一样的help,这里不列了。

用alc5640进行mixer控制的用法：

# alsa_amixer -c 2 controls

如下：

alsa_amixer -c 2 controls

numid=35,iface=MIXER,name=‘Headphone Switch‘

numid=20,iface=MIXER,name=‘Mono ADC Capture Volume‘

numid=122,iface=MIXER,name=‘Mono ADC L1 Mux‘

numid=123,iface=MIXER,name=‘Mono ADC L2 Mux‘

numid=114,iface=MIXER,name=‘Mono ADC MIXL ADC1 Switch‘

numid=115,iface=MIXER,name=‘Mono ADC MIXL ADC2 Switch‘

numid=112,iface=MIXER,name=‘Mono ADC MIXR ADC1 Switch‘

numid=113,iface=MIXER,name=‘Mono ADC MIXR ADC2 Switch‘

numid=121,iface=MIXER,name=‘Mono ADC R1 Mux‘

numid=120,iface=MIXER,name=‘Mono ADC R2 Mux‘

numid=93,iface=MIXER,name=‘Mono DAC MIXL DAC L1 Switch‘

numid=94,iface=MIXER,name=‘Mono DAC MIXL DAC L2 Switch‘

numid=95,iface=MIXER,name=‘Mono DAC MIXL DAC R2 Switch‘

numid=92,iface=MIXER,name=‘Mono DAC MIXR DAC L2 Switch‘

numid=90,iface=MIXER,name=‘Mono DAC MIXR DAC R1 Switch‘

numid=91,iface=MIXER,name=‘Mono DAC MIXR DAC R2 Switch‘

numid=11,iface=MIXER,name=‘Mono DAC Playback Volume‘

numid=44,iface=MIXER,name=‘Mono MIX BST1 Switch‘

numid=41,iface=MIXER,name=‘Mono MIX DAC L2 Switch‘

numid=40,iface=MIXER,name=‘Mono MIX DAC R2 Switch‘

numid=43,iface=MIXER,name=‘Mono MIX OUTVOL L Switch‘

numid=42,iface=MIXER,name=‘Mono MIX OUTVOL R Switch‘

numid=85,iface=MIXER,name=‘Mono dacr Mux‘

numid=8,iface=MIXER,name=‘Mono Playback Switch‘

numid=21,iface=MIXER,name=‘ADC Boost Gain‘

numid=24,iface=MIXER,name=‘ADC IF1 Data Switch‘

numid=26,iface=MIXER,name=‘ADC IF2 Data Switch‘

numid=18,iface=MIXER,name=‘ADC Capture Switch‘

numid=19,iface=MIXER,name=‘ADC Capture Volume‘

numid=22,iface=MIXER,name=‘Class D SPK Ratio Control‘

numid=25,iface=MIXER,name=‘DAC IF1 Data Switch‘

numid=27,iface=MIXER,name=‘DAC IF2 Data Switch‘

numid=103,iface=MIXER,name=‘DAC L2 Mux‘

numid=107,iface=MIXER,name=‘DAC MIXL INF1 Switch‘

numid=106,iface=MIXER,name=‘DAC MIXL Stereo ADC Switch‘

numid=105,iface=MIXER,name=‘DAC MIXR INF1 Switch‘

numid=104,iface=MIXER,name=‘DAC MIXR Stereo ADC Switch‘

numid=102,iface=MIXER,name=‘DAC R2 Mux‘

numid=10,iface=MIXER,name=‘DAC1 Playback Volume‘

numid=9,iface=MIXER,name=‘DAC2 Playback Switch‘

numid=108,iface=MIXER,name=‘DAI select‘

numid=88,iface=MIXER,name=‘DIG MIXL DAC L1 Switch‘

numid=89,iface=MIXER,name=‘DIG MIXL DAC L2 Switch‘

numid=86,iface=MIXER,name=‘DIG MIXR DAC R1 Switch‘

numid=87,iface=MIXER,name=‘DIG MIXR DAC R2 Switch‘

numid=23,iface=MIXER,name=‘DMIC Switch‘

numid=37,iface=MIXER,name=‘Ext Spk L Switch‘

numid=38,iface=MIXER,name=‘Ext Spk R Switch‘

numid=3,iface=MIXER,name=‘HP Playback Switch‘

numid=4,iface=MIXER,name=‘HP Playback Volume‘

numid=50,iface=MIXER,name=‘HPO MIX DAC1 Switch‘

numid=49,iface=MIXER,name=‘HPO MIX DAC2 Switch‘

numid=51,iface=MIXER,name=‘HPO MIX HPVOL Switch‘

numid=36,iface=MIXER,name=‘Headset Mic Switch‘

numid=111,iface=MIXER,name=‘IF2 ADC L Mux‘

numid=110,iface=MIXER,name=‘IF2 ADC R Mux‘

numid=17,iface=MIXER,name=‘IN Capture Volume‘

numid=13,iface=MIXER,name=‘IN1 Boost‘

numid=12,iface=MIXER,name=‘IN1 Mode Control‘

numid=15,iface=MIXER,name=‘IN2 Boost‘

numid=14,iface=MIXER,name=‘IN2 Mode Control‘

numid=39,iface=MIXER,name=‘Int Mic Switch‘

numid=45,iface=MIXER,name=‘LOUT MIX DAC L1 Switch‘

numid=46,iface=MIXER,name=‘LOUT MIX DAC R1 Switch‘

numid=47,iface=MIXER,name=‘LOUT MIX OUTVOL L Switch‘

numid=48,iface=MIXER,name=‘LOUT MIX OUTVOL R Switch‘

numid=29,iface=MIXER,name=‘LPE IHF mixer‘

numid=30,iface=MIXER,name=‘LPE headset mixer‘

numid=6,iface=MIXER,name=‘OUT Channel Switch‘

numid=69,iface=MIXER,name=‘OUT MIXL BST1 Switch‘

numid=68,iface=MIXER,name=‘OUT MIXL BST3 Switch‘

numid=74,iface=MIXER,name=‘OUT MIXL DAC L1 Switch‘

numid=73,iface=MIXER,name=‘OUT MIXL DAC L2 Switch‘

numid=72,iface=MIXER,name=‘OUT MIXL DAC R2 Switch‘

numid=70,iface=MIXER,name=‘OUT MIXL INL Switch‘

numid=71,iface=MIXER,name=‘OUT MIXL REC MIXL Switch‘

numid=62,iface=MIXER,name=‘OUT MIXR BST1 Switch‘

numid=61,iface=MIXER,name=‘OUT MIXR BST2 Switch‘

numid=60,iface=MIXER,name=‘OUT MIXR BST3 Switch‘

numid=65,iface=MIXER,name=‘OUT MIXR DAC L2 Switch‘

numid=67,iface=MIXER,name=‘OUT MIXR DAC R1 Switch‘

numid=66,iface=MIXER,name=‘OUT MIXR DAC R2 Switch‘

numid=63,iface=MIXER,name=‘OUT MIXR INR Switch‘

numid=64,iface=MIXER,name=‘OUT MIXR REC MIXR Switch‘

numid=5,iface=MIXER,name=‘OUT Playback Switch‘

numid=7,iface=MIXER,name=‘OUT Playback Volume‘

numid=138,iface=MIXER,name=‘RECMIXL BST1 Switch‘

numid=137,iface=MIXER,name=‘RECMIXL BST2 Switch‘

numid=136,iface=MIXER,name=‘RECMIXL BST3 Switch‘

numid=134,iface=MIXER,name=‘RECMIXL HPOL Switch‘

numid=135,iface=MIXER,name=‘RECMIXL INL Switch‘

numid=139,iface=MIXER,name=‘RECMIXL OUT MIXL Switch‘

numid=132,iface=MIXER,name=‘RECMIXR BST1 Switch‘

numid=131,iface=MIXER,name=‘RECMIXR BST2 Switch‘

numid=130,iface=MIXER,name=‘RECMIXR BST3 Switch‘

numid=128,iface=MIXER,name=‘RECMIXR HPOR Switch‘

numid=129,iface=MIXER,name=‘RECMIXR INR Switch‘

numid=133,iface=MIXER,name=‘RECMIXR OUT MIXR Switch‘

numid=28,iface=MIXER,name=‘Register Control‘

numid=109,iface=MIXER,name=‘SDI select‘

numid=82,iface=MIXER,name=‘SPK MIXL DAC L1 Switch‘

numid=83,iface=MIXER,name=‘SPK MIXL DAC L2 Switch‘

numid=81,iface=MIXER,name=‘SPK MIXL INL Switch‘

numid=84,iface=MIXER,name=‘SPK MIXL OUT MIXL Switch‘

numid=80,iface=MIXER,name=‘SPK MIXL REC MIXL Switch‘

numid=77,iface=MIXER,name=‘SPK MIXR DAC R1 Switch‘

numid=78,iface=MIXER,name=‘SPK MIXR DAC R2 Switch‘

numid=76,iface=MIXER,name=‘SPK MIXR INR Switch‘

numid=79,iface=MIXER,name=‘SPK MIXR OUT MIXR Switch‘

numid=75,iface=MIXER,name=‘SPK MIXR REC MIXR Switch‘

numid=59,iface=MIXER,name=‘SPOL MIX BST1 Switch‘

numid=56,iface=MIXER,name=‘SPOL MIX DAC L1 Switch‘

numid=55,iface=MIXER,name=‘SPOL MIX DAC R1 Switch‘

numid=58,iface=MIXER,name=‘SPOL MIX SPKVOL L Switch‘

numid=57,iface=MIXER,name=‘SPOL MIX SPKVOL R Switch‘

numid=54,iface=MIXER,name=‘SPOR MIX BST1 Switch‘

numid=52,iface=MIXER,name=‘SPOR MIX DAC R1 Switch‘

numid=53,iface=MIXER,name=‘SPOR MIX SPKVOL R Switch‘

numid=32,iface=MIXER,name=‘SSP BT Master Mode‘

numid=34,iface=MIXER,name=‘SSP Modem Master Mode‘

numid=33,iface=MIXER,name=‘SSP VOIP Master Mode‘

numid=31,iface=MIXER,name=‘SST Probe Byte Control‘

numid=16,iface=MIXER,name=‘Speaker Boost‘

numid=1,iface=MIXER,name=‘Speaker Playback Switch‘

numid=2,iface=MIXER,name=‘Speaker Playback Volume‘

numid=125,iface=MIXER,name=‘Stereo ADC L1 Mux‘

numid=127,iface=MIXER,name=‘Stereo ADC L2 Mux‘

numid=118,iface=MIXER,name=‘Stereo ADC MIXL ADC1 Switch‘

numid=119,iface=MIXER,name=‘Stereo ADC MIXL ADC2 Switch‘

numid=116,iface=MIXER,name=‘Stereo ADC MIXR ADC1 Switch‘

numid=117,iface=MIXER,name=‘Stereo ADC MIXR ADC2 Switch‘

numid=124,iface=MIXER,name=‘Stereo ADC R1 Mux‘

numid=126,iface=MIXER,name=‘Stereo ADC R2 Mux‘

numid=101,iface=MIXER,name=‘Stereo DAC MIXL ANC Switch‘

numid=99,iface=MIXER,name=‘Stereo DAC MIXL DAC L1 Switch‘

numid=100,iface=MIXER,name=‘Stereo DAC MIXL DAC L2 Switch‘

numid=98,iface=MIXER,name=‘Stereo DAC MIXR ANC Switch‘

numid=96,iface=MIXER,name=‘Stereo DAC MIXR DAC R1 Switch‘

numid=97,iface=MIXER,name=‘Stereo DAC MIXR DAC R2 Switch‘

alsa_amixer -c 2 cget numid=2 // 从card2 获得主喇叭当时的音量

alsa_amixer -c 2 cset numid=2 39　// 从card2设置主喇叭的音量＝39

alsa_amixer -c 2 cset numid=2 100%　// 从card2设置主喇叭的音量＝39