Raspberry Pi(数莓派)声音输出的设置

声音输出可设置为自动，耳机输出，从HDMI输出三种，默认为自动

pi@aborn ~ $ sudo apt-get install alsa-utils
pi@aborn ~ $ sudo modprobe snd-bcm2835    #把声音模块加入内核
pi@aborn ~ $ sudo aplay /usr/share/sounds/alsa/Front_Center.wav 
pi@aborn /opt/vc $ sudo amixer cset numid=3 2
numid=3,iface=MIXER,name='PCM Playback Route'
; type=INTEGER,access=rw------,values=1,min=0,max=2,step=0
: values=2
pi@aborn /opt/vc $ sudo aplay /usr/share/sounds/alsa/Front_Center.wav 
Playing WAVE '/usr/share/sounds/alsa/Front_Center.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono
pi@aborn /opt/vc $ sudo amixer cset numid=3 
numid=3,iface=MIXER,name='PCM Playback Route'
; type=INTEGER,access=rw------,values=1,min=0,max=2,step=0
: values=0
pi@aborn /opt/vc $ sudo amixer cset numid=3 1
numid=3,iface=MIXER,name='PCM Playback Route'
; type=INTEGER,access=rw------,values=1,min=0,max=2,step=0
: values=1

values取不同的值分别代表：
0=auto(自动), 1=headphones(耳机), 2=hdmi 

我发现播放视频的时候非常消耗cpu资源

参考：http://raspberrypi.stackexchange.com/questions/44/why-is-my-audio-sound-output-not-working