[mythtv-users] Stereo sound works over optical link but surround doesn't

[Ole Wolf]

I'm attempting to get surround sound audio out to my amplifier via an  
optical S/PDIF cable.

I have a Creative Audigy 2 card and a Creative Digital I/O module (the  
one that is plugged into the Audigy 2 digital output to provide  
optical I/O). I can play back surround sound on my amplifier via the  
analog outputs from the Audigy 2; however, the optical connection only  
allows me to play back stereo sound.

I realize that I may have to encode the output as AC3, but when I type:

   $ mplayer -ao alsa -ac hwac3 filename.ac3

for hardware AC3 encoding, mplayer complains that:

   Unknown option on the command line: -hwac3
   Error parsing option on the command line: -hwac3

I'm gathering from  
http://www.mplayerhq.hu/DOCS/HTML/en/audio-codecs.html#hwac3 Section  
7.2.2, "Hardware AC-3 decoding," that I may have to buy a Sound  
Blaster Live 24-bit card. However, I'd rather not shell out that money  
if I'm just doing something wrong.

Has anyone managed to play back surround sound via an optical cable  
from a Creative Audigy 2 sound card? If so, how?