Soundblaster Live!: with this card you can use
4 or 6 (5.1) channels AC3 decoding instead of 2. Read the
Software AC3 decoding section. For hardware AC3
passthrough you must use ALSA 0.9 with OSS emulation!
C-Media with S/PDIF out: hardware AC3
passthrough is possible with these cards, see
Hardware AC3 decoding section.
Features of other cards aren't supported by
MPlayer. It's very recommended
to read the sound card section!