Windows Vista AC3 passthrough SPDIF

[jcrabapple]

TV-Server Version:
MediaPortal Version: RC2
MediaPortal Skin:
Windows Version: Vista Ultimate
CPU Type: AMD Ahtlon X2
HDD: 300 GB
Memory: 2 GB
Motherboard: Asus M2A-VM
Video Card:
Video Card Driver:
Sound Card: Sound Blaster Live 24-bit
Sound Card AC3: Sound Blaster Live 24-bit
Sound Card Driver: newest from Creative
1. TV Card:
1. TV Card Type:
1. TV Card Driver:
2. TV Card:
2. TV Card Type:
2. TV Card Driver:
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec: ffdshow
MPEG2 Audio Codec: MPA
h.264 Video Codec: ffdshow
Satelite/CableTV Provider:
HTPC Case:
Cooling:
Power Supply:
Remote:
TV:
TV - HTPC Connection: S-Video, digital optical

If someone could help me with this I would be forever in your debt. I have Vista Ultimate, MP RC2, a Sound Blaster Live 24-bit sound card. I have ripped a bunch of my DVDs in xvid and ac3. I am trying to get my HTPC to passthrough AC3 to my new receiver which has a DD and DTS decoder. The most I get is the front left and right speakers, no center or surround. I know that it is sending surround sound because I can't hear any voices in the center channel. I only hear them when they are to the left or right, so it's not downmixing to stereo. I have searched these forums and many others and I have Googled. I can not find the right solution.

Last night I brought my HTPC down from upstairs which has XP on it. I could get it to pass AC3, because my receiver would immediately switch to DD. But even then the sound was jittery. I messed with that for a while and couldn't get it to work right either, but it's at least passing the AC3.

So that's about all the information I can give. I have tried ffdshow, MPA, and AC3Filter. Right now I am using analog surround, which just isn't the same.

I would appreciate any and all assistance.

[edterbak]

You can try a couple of suggestions which are mentioned in here. How to get bit perfect playback, DTS5.1 and Dolby Digital 5.1 in MP. There is good information in the document.
The Author is KevL. He wrote it in this threat.