Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
In article <4149ca56$0$20254$cc9e4d1f@news-text.dial.pipex.com>, "The
Berzerker" <Berzerker@wooooooo.com> wrote:
> "Paul" <nospam@needed.com> wrote in message
> news:nospam-1609040914400001@192.168.1.177...
> > In article <41496433$0$20243$cc9e4d1f@news-text.dial.pipex.com>, "The
> > Berzerker" <Berzerker@wooooooo.com> wrote:
> >
> > > My ASUS P4S800D has onboard sound via the 'ADI AD11980 SoundMAX AC '97
> audio
> > > codec'. I'm trying to use the 5.1 output functionality.... but it's not
> > > working.
> > >
> > > I've connected a coax lead to the SPDIF port, and set the soundmax
> config to
> > > a 5.1 speaker setup... however, my decoder still only receives a stereo
> > > signal. So, I'm totally lost as of what to do...
> > >
> > > I can't just select 5.1 on my decoder, if it receives a 5.1 signal, it
> does
> > > it itself, if there's no 5.1 signal, it'll just show up as stereo.
> > >
> > > I hope someone can help, thanks.
> >
> > SPDIF is two channels (stereo). Dolby Digital is a special encoding
> > that squeezes 5.1 content into those stereo channels. To create
> > Dolby Digital requires a license from Dolby Labs, so you won't find
> > too many computer setups with the ability to create Dolby Digital
> > content in real time.
> >
> > The best way to test that your SPDIF can carry Dolby Digital, is
> > to use your DVD player on the computer, to play a movie which has
> > the sound track encoded in Dolby Digital. The DVD software will
> > simply pass the audio samples, with their special encoding,
> > directly to the SPDIF interface. Your receiver should then play
> > the movie soundtrack in 5.1.
> >
> > Very little other content will do this, unless the content provider
> > paid for a license. There are probably software programs for
> > creating Dolby Digital content from multichannel source, but expect
> > them to be expensive.
> >
> > The only hardware solution I know of, is the Nvidia Nforce2 MCP-T
> > Southbridge. It has a digital signal processing core in silicon,
> > and Nvidia has a license from Dolby, to create 5.1 content suitable
> > for playing on the SPDIF. That means someone with a A7N8X-E Deluxe
> > can play 5.1 via a hardware route. Other chipsets don't have that
> > capability.
> >
> > HTH,
> > Paul
>
> Thanks Paul, that's fantastic. By selecting use SPDIF in powerdvd's options
> (something I had overlooked) I now receive a 5.1 signal, however, I'm still
> a little lost.
>
> While the dvd being in 5.1 is dandy, I really want to use the 5.1 system for
> games. However, I still cannot receive anything other than a stereo signal
> (outside of powerdvd). I'm trying on both painkiller and Doom 3, both games
> being 5.1 capable. You have any ideas? I'm almost certain that it should be
> outputting a 5.1 signal all the time, because there's even a test utility in
> the soundmax setup panel..... it rotates static noise around the speakers,
> but because the decoder is still getting stereo, you don't hear the rear
> speakers. There must just be a freakin' check box laying around on my PC
> that'll enable the use of the SPDIF port all the time.
>
> You've done great so far, any other ideas???
>
> Chris
It is good you've proved it can work. But, as I explained in my first
post, for a program (computer game, multimedia application etc) to
produce Dolby Digital 5.1 encoding for the SPDIF, there is a license
required. This adds to the cost of software products, so you are
unlikely to find software to do it. In addition, the encoding process
would add some delay, between the time a game made the sound, until
it actually arrived at your theatre system. I don't think you would
appreciate hearing machine gun fire, _after_ you were already dead
in your game
I tried researching this earlier, and it is possible there is some
encoding software out there. What that software would do for you,
is allow, say, music source material, to be encoded in a manner suitable
for sending to the SPDIF at a later time. I haven't run into any
real time "driver", that can fool the OS into thinking it is a
virtual sound output device, and then doing encoding on the fly to
drive the SPDIF. As I said in the first paragraph, there would be
appreciable delay in such a process, so it would be suitable for
music purposes but not for games. The reason this is a workable
solution on the A7N8X-E Deluxe, is the encoding process is done
in hardware by a DSP core in the Southbridge.
HTH,
Paul
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