http://www.mythtv.org/wiki/Configuring_Digital_Sound_with_AC3_and_SPDIF
aplay -D spdif -c 2 -f S16_LE -r 48000 -t raw /dev/urandom
aplay -D hw:0,4 -c 2 -f S16_LE -r 48000 -t raw /dev/urandom
mplayer -ao alsa:device=spdif -ac hwac3 test.ac3
check .asoundrc files
ChoGall/home/samba/public/Documents/Inspiron