SPDIF & Analog Audio in Vista

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pyedp1per

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#24608 28-Jul-2008 22:58

Many people who are using vista for media centre have probably found that you can't output digital and analog audio at the same time. How annoying!

Has any one found a way around this?

I have no worries outputting digital from the optical jack, coaxial/RCA jack and HDMI on my NVidia 9600GT (the audio is passed from the motherboard and straight onto the graphics card via a 2 pin plug) all at the same time.

I have looked into VAC - Virtual Audio Cable which enables simultaneous outputs, however only with stereo. VAC can't handle Dolby Digital or DTS, so you can only get stereo from both outputs.

A popular device to get around this problem was the Creative DDTS-100, which looks like it would do the job. However these are no longer made and seem to be very rare. Another hardware device is the Gefen Digital Audio to Analog Adapter, but this will only convert 2 channel PCM.

It seems that most solutions that are available can only do digital and analog at the same time will only do it if the source is stereo and can't downmix 5.1 to stereo.

Any ideas!

eXDee

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#152254 29-Jul-2008 00:05

This isn't really related, but your problem made me think of this. Highly unlikely to be causing your problem, but its a good read.

Anyway, on topic, googling seems to say that microsoft has acknowledged the issue and is apparently 'fixing it' but apparently its also 'hard coded' into the [MCE] application or something.

sbiddle

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#152270 29-Jul-2008 06:49

What audio chipset are you using? If it's a realtek there is a patch to get simultaneous spdif and analog but it's setereo only - you can't get 5.1 and stereo analogue simultaneously due to the DRM restrictions in Vista.

I have read posts where people have purchased external SPDIF -> analog decoders so you split the SPDIF signal into two and run one to your amp and one to the decoder. Many of the cheaper units will only handle stereo SPDIF and not decode 5.1 -> stereo so be wary if you do want to go down this path.

pyedp1per

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#152289 29-Jul-2008 08:45

The realtek driver trick won't help me because I want 5.1 as well.

So it seems I'll need a piece of hardware to do this. Anyone know of a piece of hardware that will convert digital to analog including 5.1 Dolby Digital & DTS bitstreams?

Nety

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#152293 29-Jul-2008 08:48

I thought I finally had a fix to this with Creatives latest drivers for their soundcards but alas not.

With my Audigy I also can get stereo to feed to both spdif and analog but only when in stereo as soon as 5.1 starts the analog shuts up as does my TV which does not down convert.

The latest driver allows you to get the soundcard to decode digital sources. That allowed me to get sound from the TV for movies etc but the problem is then it feeds the amp the decoded stream which of course stops that from getting 5.1... grrr

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sbiddle

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#152296 29-Jul-2008 09:02

pyedp1per: The realtek driver trick won't help me because I want 5.1 as well.

So it seems I'll need a piece of hardware to do this. Anyone know of a piece of hardware that will convert digital to analog including 5.1 Dolby Digital & DTS bitstreams?

These have been a popular choice http://www.trittontechnologies.com/products/TRIGA600.htm

Only does Dolby though

richms

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#152462 29-Jul-2008 16:48

This is to be expected, since there is no reason that a soundcard would be doing a dolby digital decode and downmix.

The only way it would be possible is if the player software was to open the 2 sound devices as 2 seperate devices and send decoded and downmixed audio to one, and the bitstream to the other. This may be possible on HD audio since the front jacks have the option of being a seperate device and can take stereo audio while a bitstream is being played out the spdif, but the software would have to support it, and there is really no reason to do so when most people are only interested in playing out one device at a time.

Richard rich.ms

sbiddle

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#152467 29-Jul-2008 17:10

This issue is something I spent a lot of time playing with. Ideally I'd like to have my PVR sending AC3 5.1 via SPDIF to my amp but only analogue stereo to my TV. This means if something is in 5.1 I can turn the amp on but if I'm just watching something else and don't care about the sound I can use the TV's audio.

It's something easily done in XP but unfortunately damn near impossible in Vista. :-(

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dolsen

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#152478 29-Jul-2008 17:44

sbiddle:

It's something easily done in XP but unfortunately damn near impossible in Vista. :-(

Yeah – for this reason I regret buying Vista for my HTPC. If I had known about this, I would have stuck with XP. It's very annoying that this is crippled in such a way.

Here’s a link where someone says that this is being worked on, and will supposedly be fixed at some indeterminate point in the future, but, who knows what timeframe we will be waiting…

http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=3270398&SiteID=17