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Proper Audio Playback Setting?

post #1 of 8
11/28/12 at 1:41pm
Thread Starter 
Hey folks. Hope this is in the right place. First my setup. I have an HTPC with an Nvidia GTX 460 going HDMI out to an Onkyo HT-S5400 home theater system which is set to PLIIz Height.

For a long time in the sound device playback settings for my GTX 460 I had it set to 5.1 surround, but recently I was messing around, and found that I can still hear 5.1 surround when I select stereo. Is this because the receiver just takes the signal and outputs it correctly? If so, what's the proper playback setting, stereo or 5.1?

Some of the benefits I notice from setting playback to stereo is that I can now hear 5.1 Youtube videos in surround. And I've been able to resolve some Windows Media Center issues (For instance, OTA TV would stutter and just stop working with 5.1, and with stereo enabled in the playback settings, but 5.1 chosen in the WMC settings I'm able to hear Netflix movies in surround).
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post #2 of 8
11/28/12 at 3:51pm
The channel count in the sound playback control panel refers to LPCM (i.e. uncompressed) audio streams. If you select 5.1 here, then

- Stereo LPCM: Silent sound will be added to the surround speakers by Windows Audio Engine. PLIIx in the receiver won't work.
- 5.1 LPCM: The audio stream is transmitted to the receiver as is (up to resampling by Windows Audio Engine).
- 7.1 LPCM: 7.1 will be downmixed to 5.1 by Windows Audio Engine.
- Compressed audio stream such as DD, DD+, TrueHD, DTS, DTS-HD HRA/MA: The stream is transmitted as is to the receiver.

If you select "Stereo",

- Stereo LPCM: The audio stream is transmitted to the receiver as is and expanded to surround sounds by PLIIx in the receiver.
- 5.1/7.1 LPCM: The audio stream will be downmixed to stereo by Windows Audio Engine (hence information will be lost) and will be expanded to surround sounds by PLIIx in the receiver.
- Compressed audio stream such as DD, DD+, TrueHD, DTS, DTS-HD HRA/MA: The stream is transmitted as is to the receiver.

"Stereo" is often a better choice, except for multichannel LPCM. Many audiophiles use WASAPI exclusive mode that completely bypasses Windows Audio Engine, but this mode won't work with WMC.
Edited by renethx - 11/28/12 at 3:59pm
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post #3 of 8
11/28/12 at 4:23pm
Thread Starter 
Wow. Very informative (maybe too informative). Thank you. So using WASAPI exclusive mode, isn't that done through whatever player I'm using? And what's an example of a file that uses a multichannel LPCM format? Does bluray and dvd use LPCM, or do they rely on DTS-HD or TrueHD? I'm sorry for the dumb questions... I've been on this forum for years now, and so much of this stuff still seems alien to me.
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post #4 of 8
11/28/12 at 4:43pm
Some player support WASAPI exclusive mode natively, some support it with ReClock audio renderer.

Roughly ~10% of all BD movies use multichannel LPCM as the primary audio track (these movies usually include "lossy" DD/DTS audio tracks too).
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post #5 of 8
11/28/12 at 4:49pm
Thread Starter 
Quote:
Originally Posted by renethx View Post

Some player support WASAPI exclusive mode natively, some support it with ReClock audio renderer.
Roughly ~10% of all BD movies use multichannel LPCM as the primary audio track (these movies usually include "lossy" DD/DTS audio tracks too).

Ok, so the optimal setup for me would probably be to select stereo in playback, then setup ReClock for something like MPC-HC for those few films I might watch that use multichannel LPCM, correct? If so, all I have to do now is figure out how to correctly setup ReClock. I've messed around with it before, but could never figure out exactly what I was doing so that it would turn green (I was usually stuck with it in yellow).
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post #6 of 8
11/28/12 at 5:00pm
MPC-HC (or any customizable DirectShow player) + ReClock in WASAPI exclusive mode is the quickest way to get multichannel LPCM as is (i.e. no intervention by Windows Audio Engine). Yellow/Green has nothing to do with audio. Yellow is warning that the refresh rate of the graphics card does not match the frame rate of the video stream (that results in repeated frames in a uniform pattern like 2:3, some people notice is as judder). Unless you see a problem in video, you can ignore it.

J.River Media Center supports WASAPI exclusive mode natively.
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post #7 of 8
11/28/12 at 5:00pm
i think overall, you are best off leaving it at 5.1.
The only thing you lose in the process is the ability to upmix stereo, which isn't that big of a deal.
When you choose stereo, you kinda ruin things that are already surround sound, because everything becomes just stereo upmixed.

The solution to your lack of surround sound problem is that you need to find more content with surround sound, rather than rely on the upmix. Youtube and netflix for pc don't have surround sound.
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post #8 of 8
11/28/12 at 5:12pm
Thread Starter 
Quote:
Originally Posted by renethx View Post

MPC-HC (or any customizable DirectShow player) + ReClock in WASAPI exclusive mode is the quickest way to get multichannel LPCM as is (i.e. no intervention by Windows Audio Engine). Yellow/Green has nothing to do with audio. Yellow is warning that the refresh rate of the graphics card does not match the frame rate of the video stream (that results in repeated frames in a uniform pattern like 2:3, some people notice is as judder). Unless you see a problem in video, you can ignore it.
J.River Media Center supports WASAPI exclusive mode natively.

Good to know. Thanks so much for your help.
Quote:
Originally Posted by MlNDBOMB View Post

i think overall, you are best off leaving it at 5.1.
The only thing you lose in the process is the ability to upmix stereo, which isn't that big of a deal.
When you choose stereo, you kinda ruin things that are already surround sound, because everything becomes just stereo upmixed.
The solution to your lack of surround sound problem is that you need to find more content with surround sound, rather than rely on the upmix. Youtube and netflix for pc don't have surround sound.

Hmm. Well that sounds like a good point, especially for something like video games, but when I listen to 5.1 Youtube videos or Netflix in WMC I do hear surround sound, and I'm not talking just multichannel filler either, I actually hear distinct sounds moving left and right, and front and back with stereo selected. For films, it sounds like nothing will be affected at all as long as I'm running in WASAPI exclusive mode (for those 10% of films that use multichannel LPCM). So really, the only thing that it sounds like will be affected is games. Unless I'm missing something. I'm probably missing something, aren't I. smile.gif
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