I recently got a old Dell 4600c and decide to set it as my media PC. It has a digital audio output(optical fible, SPDIF) w/ soundmax as well as the normal 5.1 analog 3.5mm miniport. I also has a receiver Onkyo SR304 can decode DTS/DD/Dolby Logic/PCM. And I have some music files in lossless format ape/flac. I usually play them back by foobar2000. There is also the video files ripped from DVD w/ 5.1 AC3 audio. I usually play them back by media player classic.

I know when you play DVD disk, one can set the audio as by-pass in both the playback software and sound-card setting and send the DD/DTS signal directly into the receiver. And I figure the best sound-quality should be only decode the lossless file into the original PCM/WAV and send them to receiver by the digital (optical) cable. Is that right? How to set everything to do it? Similarly, in the video file playback, I should decode this AC3 and put them through the digital cable. (Can you send 5.1 channel raw data through SPDIF cable?) I cannot figure out how to do this. Can anyone share some light on this? Thanks.

BTW: I put it into the windows xp pro.