l 下载alsa-utils, alsa-lib, 版本要一致
http://www.alsa-project.org/main/index.php/Download
l 编译alsa-lib
./configure --host=arm-none-linux-gnueabi --disable-python --prefix=/usr/share/arm-alsa/
如果出现下列错误信息,--disable-pyhont
collect2: ld returned 1 exit status
make[3]: *** [smixer-python.la] 错误 1
make[3]: Leaving directory `/home/enzo/work/tq2440/alsa/alsa-lib-1.0.26/
modules/mixer/simple‘
make[2]: *** [all-recursive] 错误 1
make[2]: Leaving directory `/home/enzo/work/tq2440/alsa/alsa-lib-1.0.26/
modules/mixer‘
make[1]: *** [all-recursive] 错误 1
make[1]: Leaving directory `/home/enzo/work/tq2440/alsa/alsa-lib-1.0.26/
modules‘
--with-alsa-inc-prefix和--with-alsa-prefix分别指定了交叉编译util应用所需要的alsa- lib的头文件和库文件;--disable-alsamixer表示不编译生成alsamixer这个应用程序,因为该程序依赖于ncurses这个图 形界面库,目前我们对于该库还不能交叉编译,故放弃
变换到root身份
# sudo su
alsa-lib在make install时还需要交叉编译,因此需要将交叉编译器的路径加入到PATH环境变量中
#export PATH=$PATH:/usr/local/arm/4.3.2/bin && make install
l 编译alsa-utils
./configure --host=arm-none-linux-gnueabi --prefix=/usr/share/arm-alsa/ --with-alsa-inc-prefix=/usr/share/arm-alsa/include --with-alsa-prefix=/usr/share/arm-alsa/lib --disable-xmlto --disable-alsamixer
l 复制alsa-lib, alsa-utils 到开发板
开发板的复制路径不是随便设置,必须和主机编译时相同的路径,否则动态库无法找到某些文件
所以要把/usr/share/arm-alsa文件夹得内容复制到开发板/usr/share/arm-alsa
复制alsa lib到开发板/lib文件夹下
/dev 目录下已经包含一下设备
/dev/controlC0 ,/dev/pcmC0D0p , /dev/pcmC0D0c, /dev/mixer, /dev/timer
[[email protected] /]# ls /dev/pcm*
/dev/pcmC0D0c /dev/pcmC0D0p
[[email protected] /]# ls /dev/con*
/dev/console /dev/controlC0
[[email protected] /]# ls /dev/mix*
/dev/mice /dev/mixer
[[email protected] /]# ls /dev/tim*
/dev/timer
测试aplay程序
[[email protected] bin]# ./aplay test1.wav
ALSA lib confmisc.c:768:(parse_card) cannot find card ‘0‘
ALSA lib conf.c:4246:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib conf.c:4246:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name
ALSA lib conf.c:4246:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:4725:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM default
aplay: main:696: audio open error: No such file or directory
此时需要创建声卡节点到/dev/snd/
需要手动创建节点
if [ ! -d /dev/snd/ ]; then
echo "make snd node."
mkdir /dev/snd
ln -s /dev/pcmC0D0c /dev/snd/pcmC0D0c
ln -s /dev/pcmC0D0p /dev/snd/pcmC0D0p
ln -s /dev/timer /dev/snd/timer
ln -s /dev/controlC0 /dev/snd/controlC0
ln -s /dev/mixer /dev/snd/mixer
fi
export PATH=$PATH:/usr/share/arm-alsa/bin
export ALSA_CONFIG_PATH=/usr/share/arm-alsa/share/alsa/alsa.conf
# volumn设置声音大小
amixer cset numid=1 45
成功配置后
l Alsa声卡配置
** alsa声卡可以正常工作,amixer 设置
*** amixer 用法
#amixer cset numid=N value //设置变量,numid对应contents的id
#amixer cget numid=N //获取amixer的某个设置
[root@EmbedSky /mnt]# amixer contents
numid=1,iface=MIXER,name=‘Master Playback Volume‘
; type=INTEGER,access=rw------,values=1,min=0,max=63,step=0
: values=50
numid=7,iface=MIXER,name=‘Tone Control - Bass‘
; type=INTEGER,access=rw------,values=1,min=0,max=15,step=0
: values=0
numid=8,iface=MIXER,name=‘Tone Control - Treble‘
; type=INTEGER,access=rw------,values=1,min=0,max=3,step=0
: values=0
numid=10,iface=MIXER,name=‘PCM Playback De-emphasis‘
; type=ENUMERATED,access=rw------,values=1,items=4
; Item #0 ‘None‘
; Item #1 ‘32Khz‘
; Item #2 ‘44.1Khz‘
; Item #3 ‘48Khz‘
: values=0
numid=5,iface=MIXER,name=‘Mic Sensitivity‘
; type=INTEGER,access=rw------,values=1,min=0,max=7,step=0
: values=1
numid=6,iface=MIXER,name=‘Mic Volume‘
; type=INTEGER,access=rw------,values=1,min=0,max=31,step=0
: values=0
numid=16,iface=MIXER,name=‘ADC +6dB Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=17,iface=MIXER,name=‘ADC Polarity Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=2,iface=MIXER,name=‘Capture Volume‘
; type=INTEGER,access=rw------,values=1,min=0,max=7,step=0
: values=1
numid=12,iface=MIXER,name=‘AGC Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=13,iface=MIXER,name=‘AGC Target Volume‘
; type=INTEGER,access=rw------,values=1,min=0,max=3,step=0
: values=3
numid=14,iface=MIXER,name=‘AGC Timing‘
; type=INTEGER,access=rw------,values=1,min=0,max=7,step=0
: values=0
numid=3,iface=MIXER,name=‘Analog1 Volume‘
; type=INTEGER,access=rw------,values=1,min=0,max=31,step=0
: values=27
numid=4,iface=MIXER,name=‘Analog2 Volume‘
; type=INTEGER,access=rw------,values=1,min=0,max=31,step=0
: values=27
numid=15,iface=MIXER,name=‘DAC +6dB Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=18,iface=MIXER,name=‘DAC Polarity Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=20,iface=MIXER,name=‘DC Filter Enable Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=19,iface=MIXER,name=‘Double Speed Playback Switch‘
; type=BOOLEAN,access=rw------,values=1
: values=off
numid=11,iface=MIXER,name=‘Input Mux‘
; type=ENUMERATED,access=rw------,values=1,items=4
; Item #0 ‘Differential‘
; Item #1 ‘Analog1‘
; Item #2 ‘Analog2‘
; Item #3 ‘Both‘
: values=0
numid=9,iface=MIXER,name=‘Sound Processing Filter‘
; type=ENUMERATED,access=rw------,values=1,items=4
; Item #0 ‘Flat‘
; Item #1 ‘Minimum1‘
; Item #2 ‘Minimum2‘
; Item #3 ‘Maximum‘
: values=0
l 声卡测试
** 播放
[root@EmbedSky /mnt]# aplay sound_check.wav
Playing WAVE ‘sound_check.wav‘ : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
** 录音
播放命令
arecord -d 1 -t wav -c2 -r 8000 -f S16_LE test1.wav
arecord -d 60 -t wav -c2 -r 8000 -f S16_LE test1.wav
-d 录音时间,单位秒
-c 声道数
-r 采样频率
-f 采样格式, 16bit 小端
** 播放的同时录音
1. 分别开两个终端,其中一个播放, 播放的声音无断断续续等异常
aplay sound_check.wav
另一个随机录音
arecord -d 3 -t wav -c2 -r 8000 -f S16_LE test1.wav
2. 录音1分钟, 另一个终端随机播放, 然后听录音后的文件,没有任何噪声,中断和异常
arecord -d 60 -t wav -c2 -r 8000 -f S16_LE test1.wav
aplay test1.wav
** 双声道录音后播放是否正常(未测试)
** 交叉编译其他程序:
Add included file in program: #include <alsa/asoundlib.h>
~# arm-none-linux-gnueabi-gcc -lasound -L/usr/share/arm-alsa/lib/ -I/usr/share/arm-alsa/include/ -o test my_test.c