Hack to get TrueHD and DTS-HD bitstream output to receiver

[Handruin]

I've been trying to find a way to get the higher quality audio tracks to be decoded by my Marantz receiver (TrueHD/DTS-HD) which is connected to my PC. My video card and monitor are connected via DisplayPort for proper 4K@60Hz so I'm not using HDMI for video from PC to monitor. After playing around with this for a while I've found that if I connect an HDMI cable from the Intel on-board HDMI port on the motherboard to the input of my receiver and then enable the Intel display by way of mirroring my output through windows I can get audio to transport across the HDMI cable and video to display on my monitor. Keeping in mind I have no actual display connected to my receiver for output I can force the Intel driver to play audio without video via their configuration panel. This setup is less than ideal because the 2D video performance is really poor for things like dragging windows around, etc. I think this probably has to do with Intel not being able to perform very well at 4096x2160. However when using MPC-HD with LAV filter I am able to get the bitstream output to my receiver such that it now properly decodes and displays the output type such as TrueHD, etc.

Is there another way to achieve getting the higher quality audio tracks from Blu-rays to my receiver on a windows box or am I stuck with this ugly config?

This is what it looks like from a connection stand point...

PC -> Nvidia GTX 980 > DP 1.2 > monitor
PC -> Intel 4600 > HDMI > Marantz receiver

 

[ddrueding]

I'm doing something similar, but using the DP and HDMI out of the same Titan X. No performance issues.

 

[Mercutio]

My NUC overheats after about 20 minutes of trying to push 4k video but it definitely will push DTS-MA out to my Marantz receiver.
Maybe you can get to where you need to be by reassigning inputs on your receiver?

 

[Howell]

My computer is connected to the tv, and the tv is connected to the speaker bar on the ARC connection. I'm not sure how to tell the bitstream quality but it works.

 

[Stereodude]

Is the 2D GUI rendering any better if you aren't using the HDMI output for audio? Or is that what you're complaining about? Maybe my lack of sleep (go international flights!) Isn't helping.

Frankly you're not likely to notice much of a difference between the lossless codecs and the lossy ones if you only have a 5.1 setup.

 

[Handruin]

I'm doing something similar, but using the DP and HDMI out of the same Titan X. No performance issues.

Interesting. I'm not sure what I had done wrong the first time I tried to get this working but I couldn't get my receiver to work this way. However, I tried again this morning to run the HDMI out from my 980 and it's working when I mirror the display. There's no 2D desktop performance issues now! Now I no longer need to use the SPDIF cable for audio out.

 

[Handruin]

My NUC overheats after about 20 minutes of trying to push 4k video but it definitely will push DTS-MA out to my Marantz receiver.
Maybe you can get to where you need to be by reassigning inputs on your receiver?

I only had two connections running to the receiver. One was a fiber optic SPDIF and the other was this HDMI. It sees both of them it was a matter of getting my PC to turn on the HDMI port only by way of enabling video. From what I've read the only way for HDMI to function is if there's at least a minimum video signal. Without mirroring the displays on the video card I couldn't set the HDMI as the default audio output through windows.

 

[Handruin]

My computer is connected to the tv, and the tv is connected to the speaker bar on the ARC connection. I'm not sure how to tell the bitstream quality but it works.

My receiver auto-detects the signal being sent which is how I can tell if it was working with the selected audio track or not. Up until last night it was always a PCM signal. Now when I play a movie through MPC using LAV filters, my receiver will display DTS-HD or TrueHD which is what I was trying to achieve.

 

[Mercutio]

Interesting. It looks to me like I'm going to have to build a new TV PC since my NUC is no longer adequate for my needs.

 

[Handruin]

Is the 2D GUI rendering any better if you aren't using the HDMI output for audio? Or is that what you're complaining about? Maybe my lack of sleep (go international flights!) Isn't helping.

Frankly you're not likely to notice much of a difference between the lossless codecs and the lossy ones if you only have a 5.1 setup.

I didn't try this only because after I retried what ddrueding suggested using HDMI and DP out from the same video card did things work fine.

I'm running a 2.1 setup out of my receiver. Why wouldn't I gain the benefit of the better audio format when it's being decoded properly from my receiver? For example now when I play back my rip of Between the Lines Sara Bareilles Live at the Fillmore (2008), I can select the TrueHD 96kHz track and my receiver properly decodes it.

 

[Stereodude]

I'm running a 2.1 setup out of my receiver. Why wouldn't I gain the benefit of the better audio format when it's being decoded properly from my receiver? For example now when I play back my rip of Between the Lines Sara Bareilles Live at the Fillmore (2008), I can select the TrueHD 96kHz track and my receiver properly decodes it.

Lossy codecs largely destroy subtle phase information. Multichannel audio formats don't rely on subtle phase information to recreate a 3D sound field because they have extra speakers to do that. Hence there being a minimal audible difference between them.

However your case with 2.1 is even more similar. SPDIF can handle 24/96 stereo so it's not really lossy vs. Lossless, just where the mixdown happens. Really, the discrete sub is really the only difference. Mixing down to 2.1 in your receiver vs. 2.0 in your computer should be able to achieve basically identical results due to how the formulas for mixing down are done. You actually have more control using LAV's audio mixer settings of how the mix down is done. All sorts of wonky things can happen when mixing down. Like forced dynamic range compression, discarding of the .1, etc... I've seen all sorts of reports, but never spent much time looking into it because I don't have a main listening system where I'm trying to play back 5.1 / 7.1 to stereo or 2.1.

 

[Handruin]

I might be missing something here. I'm of the understanding that TrueHD and DTS-HD are lossless codecs? Is my understanding incorrect? In the movies that I've converted through Handbrake and/or MakeMKV I've always done passthru for the audio tracks and not recompress the original tracks. There is one exception in Handbrake where I also add an additional 2-channel audio track (Prologic II) for people who don't have a device which supports either of the other too HD formats and that track is in a lossy format (which I'm not using for my own consumption). Are you saying that in my configuration I'm gaining little to no benefit with using an HDMI connection when listening to the audio through my receiver which decodes the lossless formats?

 

[Mercutio]

I believe Handy is correct that they're both internally lossless codecs, but I have no idea what is happening where as far as mixing with the channels you don't have.

 

[Handruin]

I believe Handy is correct that they're both internally lossless codecs, but I have no idea what is happening where as far as mixing with the channels you don't have.

My Marantz receiver is doing the mixdown for me which is fine with me. It must be using its own engine/algorithm for this. The manual only says:

• If multichannel signals are input, they are mixed down to 2-channel audio
and are played.
• Subwoofer signals are also output.

edit: I should add this is my way of getting a 2.1 setup with proper bass management through Audyssey Multeq XT. I can later add a 3rd speaker for a 3.1 setup.

 

[Stereodude]

I might be missing something here. I'm of the understanding that TrueHD and DTS-HD are lossless codecs? Is my understanding incorrect? In the movies that I've converted through Handbrake and/or MakeMKV I've always done passthru for the audio tracks and not recompress the original tracks. There is one exception in Handbrake where I also add an additional 2-channel audio track (Prologic II) for people who don't have a device which supports either of the other too HD formats and that track is in a lossy format (which I'm not using for my own consumption).

No, they're lossless codecs. You get bit perfect representations of the original audio out of them. A 2 channel mixdown and lossy compression aren't synonymous or connected. In your specific mentioned example, you're doing both.

Are you saying that in my configuration I'm gaining little to no benefit with using an HDMI connection when listening to the audio through my receiver which decodes the lossless formats?

In the case of a 2.1 setup, definitely. A 2 channel stereo PCM audio mixdown from one of the lossless codecs bypasses any side effects from lossy compression. Yes, there's a mixdown of channel occurring, but your receiver is also doing a mixdown also in the HDMI bitstreaming case. Using LAV's mixdown feature you can definitely get an equivalent sounding audio stream from your PC over a SPDIF connection to what you get bitstreaming the lossless audio to your receiver and letting it do the mixdown.