DTS/Dolby Digital pass-through from Sage DVD

[corykim]

My nVidia mobo outputs true Dolby Digital 5.1 whenever I play any audio source, even stereo MP3's. This does not, however, mean that I'm getting the actual audio mix engineered by the studio. What I'm getting is a live 5.1 mix, derived from stereo. My receiver is capable of the same effect -- when I play a stereo CD, it can create a 5.1 mix based on that.

Do not be fooled. If you listen critically, you will notice that the audio imaging is incorrect. It is especially noticeable if you do have TRUE 5.1 passthru for comparison. For example, I just played the Matrix DVD on both WinDVD and Sage. I used the lobby shooting spree scene as the sample. Using WinDVD and pass-thru enabled, the surround speakers play discrete sound effects, such as individual tiles cracking, individual shells tinkling to the floor, and individual bullets whizzing past.

When played through Sage, using the Intervideo Audio Decoder (not the Hauppauge one), the surround channels play a mix of the overall output. You can hear the music, and even dialog of on-screen characters (which should never be heard on the surround speakers). This is not Sage's fault -- this is the effect of the sound hardware remixing stereo and/or Dolby Pro Login into 5.1.

[justme]

Valid point about the possibility of Dynamic upmixing, instead of pass thru. Maybe a test segment is the only way to absolutely verify what is actually occuring. Some of us, like me, no longer have very good hearing. Does anyone here have the Software*/knowledge to make a test segment that would consist of of five truely distinct audio tracks? It could be something as simple as each audio track saying "center" , "rear left" etc repeatedly. By making each speakers audio so distinct someone could easily tell if their MB was dynamically upmixing.

Or maybe someone knows of a link to an existing test segment that is freely available. Granted to test it would require burning a disk, but to resolve this issue that seems like a small cost.

*I believe Sonic Foundry can do a 5.1(AC-3) mix. I say this because of an article about 5.1 mixing at this site.

[laurenglenn]

In response to AC-3 in Windows Media Player, it is possible using an AC-3 codec you can download from www.doom9.org

Maybe Frey could use this to get AC-3 to output to the SPDIF. Their codec does work with AC-3. I've played AC3 files and even DiVx files with an AC-3 track in it.

I have yet to try this with Sage to see if it does send the AC-3/DTS signal direct to the SPDIF because I use PowerDVD directly to watch most DVDs.

Lauren

[JJarmoc]

When I get home tonight I'll run some of Avia's DD5.1 test patterns through sage DVD to verify whether I'm getting true DD or an upconverted stereo signal. To my ears, it sounds like DD so far, but this test should be pretty definitive. The receiver is definitely receiving a DD signal, but the thinking here is right in that it may not be the native DD off the DVD.

[JJarmoc]

Okay, here are my results. I ran the Avia 'channel identifcation' pattern through SageTV, playing the AC3, 5.1 track. This is title 6, chapter 2. It consists of a voice and tones going around each speakers in the setup.

The receiever picks up a DD signal, and I clearly hear the voice saying 'left front' 'center' 'right front' etc. as it and the tone move from channel to channel. When a tone is on a specific channel, it is not audible on the other channels at all. I verified this by disabling my center channel speaker, and confirming I do not hear the 'center' test.

I am convinced that what I am experiencing is discrete DD 5.1

In order to make my results reproducable I'll post some specifics about my setup.

SageTv Info
Audio decoder - Intervideo (from WinDVD platinum, with DD & DTS support.)
Audio renderer - Default - I'm not sure what is actually being used here. I have the following listed as other choices; Nvidia Nforce Audio, Default Directsound, Default Waveout, and Directsound; Nvidia Nforce Audio. Is there a way to confirm which is in use?

Nforce Control Panel Settings
6 speakers
Analog & Digital output enabled
Dolby Surround encoding enabled
Dolby Digital encoding enabled
Create Center Channel enabled (this is awesome for stereo sources)

Audio Driver Version; 5.10.2917.0
DirectX Version; 5.3.0000000.900

The other issue that may be affecting things is that I has this configured through Windvd & Zoom Player before Sage supported DVD playback. It may be one of the codec settings in WinDVD, or the filtergraph I created for Zoom Player that's causing it to work for me.

Good luck to you all. If anyone else has a similar system and wants more information about my ZP or WinDVD config, let me know.

[gplasky]

Let me post some information that might be a little more conclusive.

SageTv Info
Audio decoder - NVDVD (configured for SPDIF out by NVDVD player)
Audio renderer - Directsound; Nvidia Nforce Audio (We know this is going through the nForce chipset)

Nforce Control Panel Settings
6 speakers
Digital output enabled only-no analog
Dolby Surround encoding DISABLED (grayed-out because of no analog)
Dolby Digital encoding DISABLED (NOTICE THIS)
Create Center Channel enabled (this is awesome for stereo sources)
Create LFE effects (Even more awesome-great booming effects from sub)

This is all hooked up to my Sony DD 5.1/DTS receiver thru a coxial cable.

What do these settings prove?

Any sound now from my desktop shows up on the receiver as Stereo 2.0 PCM. (The nForce chipset is doing absolutely NO DIGITAL DECODING)

I fire up NVDVD player with Terminator 2-Special Edition. I start to play.
Artisian logo with sound and laser shots.-Blue Light DD 3/2
Cyberdyne/Menu screen-NO Blue Light DD 2/0
THX scene-Blue Light DD 3/2

I fire up Sage TV. I start to play.
Artisian logo with sound and laser shots.-Blue Light DD 3/2
Cyberdyne/Menu screen-NO Blue Light DD 2/0
THX scene-Blue Light DD 3/2

This shows me I am getting discrete DD 5.1 channel sound with SPDIF passthru from SageTV.

Now if I go back in my Soundstorm control panel and enable Digital decoding-what do I get? (I'm still doing SPDIF passthru.)

Any sound from my desktop-Blue Light DD 3/2
Artisian logo with sound and laser shots.-Blue Light DD 3/2
Cyberdyne/Menu screen-Blue Light DD 3/2
THX scene-Blue Light DD 3/2

If you enable Digital Decoding on the nForce sound chip it will process everything as DD 3/2 including DD 3/2.

To tell you the truth it sounds about the same.
But if you DISABLE the nForce from doing the Digital Decoding IT SOUNDS BETTER. The sound is clearer and more distinct.
But either way you get the correct sounds coming out of the correct speakers. Laser shots traveling around. The sound of liquid metal drops coming out of the rear speakers while the laser shots are coming out of the front and side to side.

I don't have the WinDVD Intervideo decoders so I couldn't test for DTS but I am positive it will come out the same. (I mean come on-I already have Intervideo Non-CSS, NVDVD, Sonic and Elecard)

My conclusion:
SageTV handles passthru from the SPDIF correctly. Playing a DVD in Sage TV with a correctly configured decoder that provides Digital Dolby 5.1 and is set for SPDIF passthru will give you full, discrete Digital Dolby 5.1 surround sound.

If you have any questions just let me know. Hope this helps settle this discussion thread.

Gerry

[mcevers]

OK. I finally got this to work, but had to give up on PowerDVD to make it work.

I downloaded a trial copy of NVDVD and when using the NVDVD codec and Nvidia DirectSound as renderer in SageTV, the audio signal is indeed properly passed to the receiver, allowing the receiver to recognize the DTS signal and decode it.

PowerDVD, for whatever reason, will not do it when I use that codec in SageTV.

I stand corrected. Evidently there is a hook of some sort that PowerDVD can use in its own audio codec that is not working when third party applications use the codec. The Kardatzke's are redeemed, but now I'm going to have to do a lot more testing of DVD software before choosing one.

Thanks everyone for the last few posts, and if I stepped on anyone's toes, I'm sorry. That wasn't my intention.

[gplasky]

Good Point mcevers. I should have carried my testing all the way through. After reading your post it dawned on me, With the SPDIF connection, PASSTHRU is PASSTHRU. That is, I don't need a codec that supports DTS. Playing my Gladiator DVD in DTS does indeed show up as DTS on my receiver. Only if I was doing analog out would I need to be concerned if my codec supported DD or DTS because at that point the codec is doing the decoding. When I am doing passthru all the processing is done on my receiver. I tested my Sonic decoder and this works properly too. So it appears there is a problem with the PowerDVD codec properly passing the signal thru. Unless someone can show otherwise.


Gerry

[corykim]

I'm happy to report that with the NVDVD codecs, I am getting perfect DTS passthrough. Thanks for the info. One oddity that I noticed, though, is that the video is a little brighter when played through Sage than when played through NVDVD itself. Any ideas?

[gplasky]

Would it be the Hauppauge drivers affecting this? And would the options to change this be available through the advanced video (or whatever it's called) through detail settings? Just a thought.


Gerry

[corykim]

I tried manipulating the settings you're talking about, and while they affect my recordings, they have no effect on DVD output. Thanks for trying, though. :-)

[rrussell]

Quick update - I tried the NVDVD codecs and got a pretty hairy BSOD whenever anything video (either Sage or the DVD app itself) tried to play.

Oh well. El-remove-o of the NVDVD package-o.

(This was on a Via M9000, which admittedly has not got an nVidia bone in its body. I'm thinking that might've had something to do with it...)

(edited to add...)

Before I removed it, though, I tried the Cyberlink video decoder with the NVidia audio decoder, and the "Default Wave Out" audio renderer. NO digital pass-thru.

[gplasky]

Hmmm-don't you need to use a directshow filter to support spdif passthru? I didn't think wave out supported the spdif passthrough. I would think you would need to choose your default directshow device to get spdif passthru.



Gerry.

[rrussell]

"show" for audio?

Eh, ok, it's worth a shot. DYM for the decoder or the renderer? (Or both?)

Thanks!
R

[gplasky]

Just the audio renderer.

Gerry

EDIT: Sorry it is Directsound.

[mlbdude]

Anyone figure out how to use AC3Filter with Sage?

http://ac3filter.sourceforge.net/

[Narflex]

in the properties file, for the videoframe/additional_audio_filters= property, add to it:

AC3FilterName,FilterInputPin,FilterOutputPin

You'll need to get those names from GraphEdit for the AC3 filter. Then you should be able to select it in Sage and it should work.

[robn]

There was a question on how to programatically pass the AC3 stream .. I found two things.

First is the following - referring to progromatic passthrough:

Ways to Get AC3 Passthrough

There are two ways to get AC3 passthrough. The first way is for developers to use Creative's AC3API.DLL. The other way is to use a non-PCM wave output feature in Microsoft's Windows sound API to output compressed Dolby Digital or DTS signal that is read of DVD or files encoded with surround sound.

Found on: http://alive.singnet.com.sg/tech/passthrough.htm

There is also a nice AC3 filter that was written and located on Sourceforge. The project has been idle since the end of 2003, but there code can do the passthrough. Since it is open source it might give some ideas.

Found: http://www.softnews.ro/public/cat/11...1-1-2-60.shtml

Hope this helps (or is still needed ).

Robert

[robn]

This is answer is proably obvious, but I am missing it .. sorry. When you say cycle through the audio tracks, do you mean to go to the dvd menu and choose the various options (DTS, Dolby 5.1, etc..?). Or is there a method in sage to do the cycling?

I would love to try it as I am still having little luck getting the little light on the receiver to switch from stereo to Dolby Digital.

thanks!

Robert

[stanger89]

Well just to make everybody envious, DD/DTS work just fine passed through my Revo to my receiver with the Sonic Cineplayer Decoders. If you're using Sonic decoders just make sure you have SPDIF output selected in the Audio Options.

OTOH, I know the WinDVD filters are kind of funny check out my post here:
http://forums.sage.tv/forums/showthr...1975#post11975
It links to the AVS forum (which may or may not be up right now). Don't know what to tell you PDVD folks, but it's probably a similar issue to WinDVD.