# High resolution audio via HDMI



## cochinada (Feb 24, 2020)

Hello,
I'm currently using the HDMI output of my graphic card to connect to my AV processor. I would like to send the audio as is, that is, without any pc conversion and instead let my AV processor do its job.
However, I can't send True HD not any high resolution audio format although my videos have it.
There is also a strange option on the pc of sending the audio in 5.1 or 7.1
Now this certainly looks to me that windows is interfering with the sound which is exactly what I don't want!
Is there a way of sending the audio untouched via HDMI?
Should I use the HDMI of my motherboard instead?

Thank you in advance.


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## Bill_Bright (Feb 24, 2020)

Where do you see this "strange option" on the PC?

What audio out connections does your motherboard have? What motherboard?


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## Chrispy_ (Feb 24, 2020)

My Yamaha AV receiver talks directly to my GPU in Windows 10 and shows up as an RX-V683 in Windows sound settings.

If I choose Stereo, it gets 2.0 to the receiver and can use the receivers upmix options.
If I choose 5.1 I get 5.1 direct to the receiver and can either use that signal straight to the 5.1 speakers without any further processing (i.e. hear it the way it was mastered), or I can If I turn on additional Dolby/DTS options for further DSP that emulates Atmos/7.1 over my lowly 5.1 physical speakers.
If I have ARC for the TV, the sound device in Windows is sometimes shown as the TV instead of the receiver because that's the last audio device in the connection chain, but since the receiver intercepts all the sound and decodes it anyway, it doesn't make any difference. I still get the same surround options in Windows sound settings as per my AV receiver.
Regardless of whether it's Stereo or 5.1, I can still choose formats, and for my hardware, 24-bit 192KHz is possible over HDMI in 5.1 format (not that many audio/video source material is ever that good).

I wouldn't worry about the Stereo/5.1/7.1 settings in Windows. I don't think they're Windows molesting the sound, I think those surround options are shown in windows only if it detects surround-sound hardware (or software, like those virtual surround USB headphones) in the chain. Here on my work desktop, those 5.1/7.1 options don't exist because I only have stereo headphones.


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## cochinada (Feb 24, 2020)

Hi,















All my HW is described in my "System Specs".
I can't connect the HDMI to my motherboard after all because I have already my monitor connected to the Display Port of my graphic cart and this disables the output on the motherboard. I checked the BIOS and there nothing I can do otherwise...
My AV receiver is an Anthem AVM 50v and also shows up this ways on windows devices.
I'm using VLC for playing video (please see my settings).
The best I can is see 5.1 DTS on my AV receiver but when I play a bluray disc with High Definition audio, also connected via HDMI to another input of my Anthem, I can see True HD on the display.


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## Chrispy_ (Feb 25, 2020)

Ah, you want bitstreaming of source material only; That makes more sense now. I'm not keen on bitstreaming in Windows because it means that I have to manually change it back to Stereo for every single time I want to use bitstreamed audio, or live with the fact that 90% of the time, I'm running my 5.1 system in stereo. Plenty of applications and games support 5.1 native, rather than bitstreamed, which means I'm missing out of surround sound by switching back to stereo.

For my Yamaha receiver I *need to set audio in windows to Stereo* in order to bitstream - at least, I think that's what you mean you want. - it's a hangup/lowest-common-denominator from analogue soundcards I think. It would be less confusing if they labelled 'Stereo' as 'Default' instead, because technically, it's not always stereo - it's simply PCM which can be any number of channels.

The 5.1 and 7.1 options are not _bitstreaming - _they present the audio system to the application as a 5 or 7 channel device and let the application use each channel for whatever it wants.

There are a few prerequisites you need in order to bitstream that you may need to set too:

Go to BIOS and disable VT-D (Same for Intel, bitstream doesn't seem to work with VT-X either).
Ensure you have the official Nvidia GPU driver package installed, with the Nvidia HDMI audio driver. Windows update ones aren't feature complete and just have a compatibility driver.
Under your device properties, enable exclusive mode. I'm not sure this is 100% necessary but mine works and Exclusive Mode is enabled; I'm not at home to test with it disabled.


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## londiste (Feb 25, 2020)

TrueHD is a proprietary Dolby lossless codec. This should not be a goal in itself.

For movies etc, passthrough will send through untouched (usually compressed) audio from the disc, usually one of the Dolby codecs like DTS. When audio is passed through, selection like 5.1 or 7.1 in Windows should not matter.

Since you are already using HDMI for audio from computer to receiver, for games and other computer audio your best bet is simply uncompressed audio. Receivers usually show this as PCM (Pulse-code modulation).


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## cochinada (Feb 25, 2020)

Yes, I think _bitstreaming _is what I want. I don't want to do any kind of decoding in windows and want my AV processor to do it instead. So, if my movie is in DD 5.1 or DD 7.1 or DTS-ES or DTS-HD or Atmos or whatever format there is, even 2.0, I want my audio signal to be delivered unspoiled and untouched as it is to my processor because it is capable of decoding it in the best way possible. I guess this is _bitstreaming _alright.



Chrispy_ said:


> There are a few prerequisites you need in order to bitstream that you may need to set too:
> 
> Go to BIOS and disable VT-D (Same for Intel, bitstream doesn't seem to work with VT-X either).
> Ensure you have the official Nvidia GPU driver package installed, with the Nvidia HDMI audio driver. Windows update ones aren't feature complete and just have a compatibility driver.
> ...



If VT-D is the same as SR-IOV then it is disabled.
I have the latest Nvidia drivers.
I also have those two check boxes.



londiste said:


> TrueHD is a proprietary Dolby lossless codec. This should not be a goal in itself.


Sorry, but I don't understand very well what you mean. What I want is if I have a movie (I don't play games) coded in TrueHD that my Av receiver recognizes audio like that. Like I said in the beginning I can never see this format displayed on the receiver like I see it for instance if I play a bluray from my Oppo player which is also connected via HDMI so I think I must be doing something wrong...


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