做过录音的进来看一下
板子是AT91SAM9X5,用的音频芯片是WM8731，想实现录放音功能。目前能播放,不能录音。但是可以录Line-in输入的音频数据，MICIN输入的无法录。我看见Input Mux 中默认的输入是Line-in，但我改为Mic的时候再录音，arecord -f dat -d 5 -D hw:0,0 test.wav，却出错了：
Recording WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
arecord: pcm_read:1773: read error: Input/output error
下面是各参数，试着一项一项的修改，对比，但还是无果，希望大神帮忙解决！
amixer controls
numid=2,iface=MIXER,name='Master Playback ZC Switch'
numid=1,iface=MIXER,name='Master Playback Volume'主回放音量
numid=4,iface=MIXER,name='Line Capture Switch'线捕捉开关
numid=5,iface=MIXER,name='Mic Boost Volume'麦克风提高音量开关
numid=6,iface=MIXER,name='Mic Capture Switch'麦克风捕捉开关
numid=8,iface=MIXER,name='ADC High Pass Filter Switch'高通滤波器开关
numid=3,iface=MIXER,name='Capture Volume'捕捉音量
numid=10,iface=MIXER,name='Playback Deemphasis Switch'回放降低重要性开关
numid=11,iface=MIXER,name='Input Mux'输入源选择
numid=14,iface=MIXER,name='Output Mixer HiFi Playback Switch'混合输出播放开关
numid=12,iface=MIXER,name='Output Mixer Line Bypass Switch'输出混合器线绕过开关
numid=13,iface=MIXER,name='Output Mixer Mic Sidetone Switch'输出混合器麦克风侧音开关
numid=7,iface=MIXER,name='Sidetone Playback Volume'侧音播放音量
numid=9,iface=MIXER,name='Store DC Offset Switch
amixer contents
numid=2,iface=MIXER,name='Master Playback ZC Switch'
; type=BOOLEAN,access=rw------,values=2
: values=off,off
numid=1,iface=MIXER,name='Master Playback Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=127,step=0
: values=111,111
| dBscale-min=-121.00dB,step=1.00dB,mute=1
numid=4,iface=MIXER,name='Line Capture Switch'
; type=BOOLEAN,access=rw------,values=2
: values=on,on
numid=5,iface=MIXER,name='Mic Boost Volume'
; type=INTEGER,access=rw---R--,values=1,min=0,max=1,step=0
: values=0
| dBscale-min=0.00dB,step=20.00dB,mute=0
numid=6,iface=MIXER,name='Mic Capture Switch'
; type=BOOLEAN,access=rw------,values=1
: values=on
numid=8,iface=MIXER,name='ADC High Pass Filter Switch'
; type=BOOLEAN,access=rw------,values=1
: values=on
numid=3,iface=MIXER,name='Capture Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=31,step=0
: values=29,29
| dBscale-min=-34.50dB,step=1.50dB,mute=0
numid=10,iface=MIXER,name='Playback Deemphasis Switch'
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=11,iface=MIXER,name='Input Mux'
; type=ENUMERATED,access=rw------,values=1,items=2
; Item #0 'Line In'
; Item #1 'Mic'
: values=0
numid=14,iface=MIXER,name='Output Mixer HiFi Playback Switch'
; type=BOOLEAN,access=rw------,values=1
: values=on
numid=12,iface=MIXER,name='Output Mixer Line Bypass Switch'
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=13,iface=MIXER,name='Output Mixer Mic Sidetone Switch'
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=7,iface=MIXER,name='Sidetone Playback Volume'
; type=INTEGER,access=rw---R--,values=1,min=0,max=3,step=0
: values=3
| dBscale-min=-15.00dB,step=3.00dB,mute=0
numid=9,iface=MIXER,name='Store DC Offset Switch'
; type=BOOLEAN,access=rw------,values=1
: values=off
[解决办法]
