# DTS-HD HRA MA [Expert Needed]



## Ferather (Mar 29, 2021)

So I have been working on SPDIF Toslink and lossless audio for a few days, I keep hitting a bump in logic. I have facts that show that Toslink does 125Mbps or more, and the old standard (1983) is 3.1Mbps.
Now I read on Wiki and other websites that Toslink cannot do lossless due to bitrate restrictions, yet that is a lie in whole, next I see its copy rights, except analogue doesn't have any.

When I say analogue, I mean to decompress the audio and play it over 3-4x 3.5mm jacks, which blatantly doesn't have any protection, and is even suggested for lossless.
I have tested several bitrates, and cannot at all make even DTS-MA go above 30 ish Mbps, its standard is 24.5Mbps, well below 125Mbps.

Do anyone have better information? I can do 192Khz 32bit 2 channel PCM which is roughly 12mbps +, some of the DTS-MA rates are lower than this.

Does SPDIF carry the full stream, or just the core? And if core only why?

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Fiber-Optic Devices TOSLINK (digikey.com) | SPDIF (tech-faq.com)

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Same here, for Dolby Digital Plus, max rate 6Mbps.

DD+ has a variable transmission rates ranging from 96 Kbps all the way up to to 6 Mbps. As a comparison, Dolby Digital has a limit of 640 Kbps.

DD+ is transmitted via an HDMI 1.3 connection. In order to use DD+, it’s therefore important to make sure that one’s A/V receiver is equipped with an HDMI connection.
This is because the high bit rates used by DD+ can be too much for the bandwidths offered by digital or coaxial connections.









						Dolby Digital Plus: Surround sound goes multimedia
					

Dolby Digital Plus is the perfect surround sound standard for next generation applications. Learn what you need to implement this sound technology at home.




					blog.teufelaudio.com
				




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Apparently my system that does 12.228Mbps + cant do 6Mbps. Must be a joke at 1.5Mbps, which is equal to DTS core.

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So DTS-X trailer, I can see the core and its the only thing being played, but what is happening in the second and third image?







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						DTS Encoded Audio
					

MediaFire is a simple to use free service that lets you put all your photos, documents, music, and video in a single place so you can access them anywhere and share them everywhere.



					www.mediafire.com
				




All the above used the same wavs from the same source, in varying samples (48Khz, 96Khz and 192Khz).
If I play HRA vs MA, the MA sounds better and has better speaker placement, and volume.

Why is that If I get the same core with both?


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## emanresu (Mar 29, 2021)

This is an interesting question indeed.
@Jimmy9303 says DTS X is 50mbps, ask him!


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## R-T-B (Mar 29, 2021)

What source do you have that states such a high toslink bandwidth?

My guess is the cable may be able to carry that, but no commercial transcievers were ever made for it.  Thus you are effectively limited by the transciever on your mobo or whatever to PCM 2.1 bitrates, as you noted.

Even 24bit 192khz 2.1 PCM audio is tough on some mobo toslink transcievers.  You won't get more.


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## emanresu (Mar 29, 2021)

R-T-B said:


> What source do you have that states such a high toslink bandwidth?
> 
> My guess is the cable may be able to carry that, but no commercial transcievers were ever made for it.  Thus you are effectively limited by the transciever on your mobo or whatever to PCM 2.1 bitrates, as you noted.
> 
> Even 24bit 192khz 2.1 PCM audio is tough on some mobo toslink transcievers.  You won't get more.


Nice input, but do remember that 1509kbps was the limit of our belief just a few whiles ago.


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## chr0nos (Mar 29, 2021)

AFAIK its all about DRM, thats why its so limited, also to push HDMI and phase out it

EDIT:
Also on the link you posted from the "Digital Audio Optical Modules" Data rate: DC to 15 Mbps


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## R-T-B (Mar 29, 2021)

emanresu said:


> Nice input, but do remember that 1509kbps was the limit of our belief just a few whiles ago.


I just know what I've been able to eek out of it in my real world experience.


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## Ferather (Mar 30, 2021)

Latest modules are able to do 125Mps as stated in various websites (Google: Toslink 125Mbps), as far as DRM, what restricts Toslink from carrying DRM data?
Fiber optic can carry anything you send down it, no differently to internet or usb to usb PC connections, its more the working with it.

HDMI and even DiplayPort got updated, and new revisions. The reason DTS and Dobly existed was for limited bitrate.
HDMI doesn't even need compression, that's optional, it can already carry 7.1 PCM (uncompressed).

Any Toslink system that is capable of 192Khz 32bit 2 channel is already able to push 12.228 Mbps, Modules would be: 12.8Mbps, 15Mbps or 125Mbps.

Also what happens to DRM, if I uncompressed it and sent it down 3-4x 3.5mm pins?


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## Ferather (Jun 4, 2021)

So I am sending DTS an email, with the following images:

Max PCM spec, down SPDIF @ near enough HDMI eARC specs, to DTS Interactive endpoint effect.



And, Interactive off with direct digital passthrough bitstreaming on SPDIF.



Ignore the 2 channel 16 bit, I got 6 channels 24 bit.


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## Jetster (Jun 4, 2021)

SPDIF only does two channel PCM. DTS HD is 8 channel. So SPDIF will do PCM 2 channel uncompressed or compressed 5.1 DTS or DD but not DTS HD MA True HD or DD HD
And SPDIF results and completely depended in the source and the receiver


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## Ferather (Jun 5, 2021)

As far as I can tell, as you said, it's based on the hardware manufacture. In terms of processing and data, SPDIF does NOT have a bit rate limit, the module you connect to however does.
Modern Toslink modules, and cables, are up to 125mpbs (1.2 gbps I have seen), which is by far more than enough to carry 8 channel uncompressed, not even compressed.

I can say the input limit for the dedicated DTS Interactive is 36.864 mpbs, which MUST be handled by SPDIF.
New HDMI new hardware, so why not optical, we all know how good optical is.

I also read and watched videos saying eARC is only 37.5mbps.

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So my module, or Z906 can only do 36.864mbps. In WASAPI exclusive (bypasses shared mode: 24bit 48khz).

I cant receive 192khz, 8 channels, 32 bit, 49.152mbps, PCM.











						1
					

Watch "1" on Streamable.




					streamable.com
				



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I can receive 192khz, 6 channels, 32 bit, 36.864mbps, PCM.











						2
					

Watch "2" on Streamable.




					streamable.com
				




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Only supports 2 channels by default for PCM, but receives much more.


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## Ferather (Jul 12, 2021)

Case closed, current standards for Toslink support all modern formats, its more of an OEM issue, still using HD-DVD Toslink standards.
My ALC889 from 2008, does at a minimum 9mbps, 2 channels 192khz 24bit, the specs are 20-125mbps (modules).


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