Dolby Digital on SB Audigy LS

[kookywon]

Hello,

I just recently got my system up and running, and everything seems to be working correctly except for the audio. I've got a SoundBlaster Audigy LS sound card and I want to output on a Yamaha receiver with digital coax input.

The soundcard has SPDIF output (digital) as a miniplug and the receiver has digital coax input as an RCA. I bought a mono miniplug cord and a mono miniplug to mono RCA converter. When I run the diagnostic tools on headphone output I can hear stereo sound (left/right) but when I run the 5.1 setup I can only hear front right/left.

My first question is if this is the correct hardware to get the digital signal from the soundcard to the receiver for dolby digital audio? I think something's working right because I am getting sound from an output/input that is digital and not analog. However, my receiver usually displays the mode its in (pro logic/digital/dts) and its only displaying pro logic, so I assume I'm not getting the 5.1 signal.

Second, my hardware didn't come with any OEM software so I'm using the microsoft DVD codecs. I've been hearing quite a bit about the audio codecs necessary for 5.1/DTS. Do I need an audio codec to get the audio from the DVD correctly? I have read mention of nVidia pure video decoder and ffdshow. I'm not quite sure what the difference is.

[capone]

I ended up getting a $30 chaintech card w/ a s/pdif out, and use ffsdhow to pass 5.1 audio. It's more processing overhead, but it works nicely.

When it works (on a Sony) it says DD and lights up 5.1 channels.

[kookywon]

How are you passing from the card to the receiver? I'm assuming that you're using a miniplug on the card. What is the input on the receiver? RCA/miniplug?

[capone]

Optical s/pdif. The card doesn't handle the audio at all, and just is a conduit directly from the system. This is why a cheap card works fine, since the system is doing the sound processing, and the reciever is doing the output. The sound card is just a glorified outlet/jack in my setup.

[kookywon]

That's why I was asking about the connection. I'm pretty sure the card works. I know the receiver works. I'm concerned that the mono miniplug/RCA that I'm using right now isn't transferring all of the data correctly.

If I can find out the correct connection then I won't have to shell out $50+ for a new card with optical out, a new optical cable and shipping and handling.

[capone]

I had this same setup working w/ a RCA plug in a previous config (using an onboard sound card).

[kookywon]

So the mono miniplug to mono rca should be an okay connection.

It sounds like the issue might be fixed by ffdshow. This will 'force' all of the audio output to the format I choose (5.1) and the receiver will recognize it as such?

[User]

Sounds to me like the source material you are playing has a digital prologic stream. If you are getting digital out and the stream decdes as prologic at the receiver then that's what it is.

[kookywon]

I agree. However, the diagnostic software that came with the soundcard contains a test that's supposed to send a 5.1 signal out. I can hear the front right/front left parts but nothing else (no 5.1 light on the receiver either). That's why I'm wondering if I'm actually getting the 5.1 signal at the receiver or if something (the cable, or the sound card) is not transmitting correctly.

[capone]

So the mono miniplug to mono rca should be an okay connection.

It sounds like the issue might be fixed by ffdshow. This will 'force' all of the audio output to the format I choose (5.1) and the receiver will recognize it as such?

I think...I was on the phone when I read/said RCA. Is that the same as digital coax? Bottom line is if it's the s/pdif, then it should work.

Anyway, I just used KingArglye's tips from this old post:
http://forums.nextpvr.com/showthread.php...hlight=ac3

You can play w/ it, but I have ffdshow handle all uncompressed and AC3 (need to let to lib and not spdif so it gets handled) , convert all to 48Khz, handle as 5.1 (it needed to be 5.1...setting to DD/Prologic specifically dind't work...the receiver treats it as DD anyway), and output as AC3 224 only.