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Multichannel PCM/Bitstream with a gpu


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Hello all, can anybody tell me how to configure a windows pc (windows 7) to get bitstreaming from an Nvidia gpu (gtx 970) via HDMI. Currently I am receiving multichannel PCM via HDMI but would prefer to bitstream from my pc to my AVR and/or pre-pro.

Don't believe everything you read on the internet - Albert Einstein

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Well it depends what you are playing. But for the best quality video playback on a PC, you would not bitstream the audio and use software like JRiver's VideoClock, or ReClock, since the audio & video clocks are separate.

 

On HDMI, there's only single clock. Audio clock is based on the video pixel clock...

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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On HDMI, there's only single clock. Audio clock is based on the video pixel clock...
Yes, I know that should be the case.

But I've yet to find a PC that doesn't have AV sync problems without using software like this to keep the audio and video presentation in sync.

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Yes, I know that should be the case.

But I've yet to find a PC that doesn't have AV sync problems without using software like this to keep the audio and video presentation in sync.

 

It is then more about problem of the player software than HDMI itself. It is all written out in the HDMI specification, I've read it through cover to cover.

 

Usually video is associated with 48k-base audio sampling rates because it is nicely in sync with video frame rate (N samples per frame). 44.1k-base sampling rates are more tricky for both HDMI and USB because it is not a simple fraction of the clock frequency.

 

Due to the relation to video clocks, available HDMI audio bandwidth depends on video resolution. In order to have higher resolution audio / more channels, you also need to have higher resolution video.

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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Well I could speculate on why this happens, but the reality is that it's basically a problem for any PC video playback.

That's why there are, as far as I am aware, at least three separate pieces of software that implement this reclocking functionality.

And it works. When you use this software, you don't get any lip-sync errors or dropped/repeated audio/video frames.

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Well I could speculate on why this happens, but the reality is that it's basically a problem for any PC video playback.

That's why there are, as far as I am aware, at least three separate pieces of software that implement this reclocking functionality.

And it works. When you use this software, you don't get any lip-sync errors or dropped/repeated audio/video frames.

 

I've been using mostly VLC and gstreamer for video playback without problems... I don't remember seeing any problems with Windows Media Player or DVBViewer either.

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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nobody has managed to answer my question yet - can somebody please tell me HOW to switch from multichannel pcm to bitstreaming via gpu HDMI. Nvidia states it is supported and so does windows "properties" but I can't figure out how to change the setting and have searched again and again and posted in forums but everybody spirals it into something other than the simple question

Don't believe everything you read on the internet - Albert Einstein

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nobody has managed to answer my question yet - can somebody please tell me HOW to switch from multichannel pcm to bitstreaming via gpu HDMI. Nvidia states it is supported and so does windows "properties" but I can't figure out how to change the setting and have searched again and again and posted in forums but everybody spirals it into something other than the simple question

 

It entirely depends on what application you are using for playback. IIRC last time I tried things were working with

PowerDVD 14 Ultra - Blu-ray, HD, 3D & 4K Media Player Software | CyberLink

http://www.dvbviewer.com

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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nobody has managed to answer my question yet - can somebody please tell me HOW to switch from multichannel pcm to bitstreaming via gpu HDMI. Nvidia states it is supported and so does windows "properties" but I can't figure out how to change the setting and have searched again and again and posted in forums but everybody spirals it into something other than the simple question
This is an option you have to enable in your player.

In JRiver it's the "bitstreaming" options.

I prefer to decode to PCM rather than bitstream, since bitstreaming limits what you can do on the PC.

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I have several video games that are listed as having Dolby Digital and DTS sound yet I still get PCM listed.

 

What I am wanting to do is bitstream 5.1 sound so that I can expand to include additional channels via sound fields such as DTS Neo and expand stereo to 5.1 /7.1 but I always get pcm delivered to my avr and you can't expand that- unused channels appear used (they just get sent a 'blank' signal).

 

BTW - thank you for the info about the player. At least for music I can set my Jriver Media Center to bitstream and can address things that way with it.

Don't believe everything you read on the internet - Albert Einstein

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I have several video games that are listed as having Dolby Digital and DTS sound yet I still get PCM listed.
That seems like a mistake. They won't be doing DD/DTS on a PC.

You can encode to Dolby Digital or DTS with specific sound cards, but that's lower quality than PCM over HDMI so I'm not sure why you would want to.

 

Can you provide specific examples?

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That seems like a mistake. They won't be doing DD/DTS on a PC.

You can encode to Dolby Digital or DTS with specific sound cards, but that's lower quality than PCM over HDMI so I'm not sure why you would want to.

 

Can you provide specific examples?

 

 

Actually I found this which seems to answer my question regarding games

A lot of games advertise Dolby Digital, but it usually just for pre-rendered video scenes (World of Warcraft comes to mind) so the audio for those movies is compressed as AC3 (Dolby Digital).

 

Actual in game audio is dynamic (obviously) so its impossible to include a pre-encoded Dolby Digital track for it.

 

Apparently you can use DDL to encode pcm back to DD on the fly which is pointless to re-encode something once it has been decoded. It looks as if I will not be able to expand my soundfield on video games to encompass additional channels. For movies etc. I use a dedicated disc player so no troubles there - thanks everyone.

Don't believe everything you read on the internet - Albert Einstein

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nobody has managed to answer my question yet - can somebody please tell me HOW to switch from multichannel pcm to bitstreaming via gpu HDMI. Nvidia states it is supported and so does windows "properties" but I can't figure out how to change the setting and have searched again and again and posted in forums but everybody spirals it into something other than the simple question
If you tell us what you are using as a player, then we can answer your question. You don't set bitstreaming in Nvidia's software. You set it in your player software.
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Actually I found this which seems to answer my question regarding games

 

 

Apparently you can use DDL to encode pcm back to DD on the fly which is pointless to re-encode something once it has been decoded. It looks as if I will not be able to expand my soundfield on video games to encompass additional channels. For movies etc. I use a dedicated disc player so no troubles there - thanks everyone.

Ok then, that's got it - most of use are usually looking at questions that pertain to music or movies (Bluray). Games are a different matter altogether.
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It looks as if I will not be able to expand my soundfield on video games to encompass additional channels.
Again, if you provide specific examples, we may be able to give you better help.

But I don't know of any games which use Dolby Digital or DTS for audio on a PC, especially not matrixed formats.

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Yea my issue pertains mainly (almost exclusively) to games and web browsing (you tube). When I use a dedicated player such as Jriver I have found where to set the output. The

"dolby digital" claims that games make it would seem refers to cgi scenes and not in game audio which is rendered in pcm on the fly so expanding those from 5.1 to 9.2 just doesn't seem possible. Now that I have an external DAC pretty much all my 2ch audio will go through it and then out to a 2ch pre-pro and then amp.

 

What confused me was that I just recently upgraded from a gtx 580 soundcard which was limited to pcm transmission only to a gtx970 which claims to support bitstreaming and decoding the high-def codecs (Dolby True HD and DTS-HDMA)

 

from the Nvidia website description

TrueHD and DTS-HD Audio Bitstreaming

Full support for TrueHD and DTS-HD advanced lossless multi-channel HD audio codecs brings the rich sound of the master recording to your living room

 

Apparently my old 580 couldn't send bitstream even if software player told it to (like the first gen ps3) but rather had to have it transcoded to pcm and could then do multichannel pcm while the 970 will allow bitstreaming if software (player) tells it too.

 

I think at this point I have a handle on it - thank you all.

 

(also it seems many of the games that claim DD 5.1 or DTS are claims for console versions - how that is managed IDK- nor does that matter as I chose to upgrade my PC [CPU,GPU, RAM.Mobo] instead of get a next gen console)

Don't believe everything you read on the internet - Albert Einstein

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  • 2 months later...
  • 2 years later...
On 3/13/2015 at 6:03 AM, Skeptic said:

This is an option you have to enable in your player.

In JRiver it's the "bitstreaming" options.

I prefer to decode to PCM rather than bitstream, since bitstreaming limits what you can do on the PC.

 Thank you sir!!!!!!

 

I have been looking for about a week for the answer to this question. Checked every setting on every piece of hardware. Just short of cursed at LG tech support. Which I still consider terrible by the way. 

 

You mentioned that bitstreaming limits what what you can do on the PC. I can tell you this.....when I changed fro PCM to bit stream it made my Dolby audio output 100 x better. 

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