Feature Request: Enable Dolby Digital Plus (E-AC-3 or DD+) for Better Audio Quality

  • 14 September 2018
  • 34 replies
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This feature request is for Sonos support Dolby Digital Plus, also known as E-AC-3 or DD+. This would permit a higher quality audio experience when watching surround sound-enabled videos.

Sonos currently supports PCM stereo and Dolby Digital (AC-3) surround sound. This made sense for the Playbar and Playbase, which only have a S/PDIF connection.

With the Sonos Beam's HDMI ARC connection, it is now possible to deliver a Dolby Digital Plus bitstream to the Sonos 5.1 system. Many Blu-rays include a 1.5Mbps Dolby Digital Plus track. Many streaming services including iTunes, Netflix, and Amazon Prime Video support the Dolby Digital Plus codec both for efficiency and in order to deliver Dolby Atmos. Further, it is possible for an app (like Plex) to transcode in a perceptually transparent manner from lossless codecs like TrueHD and DTS:X (as well as lossy codecs like DTS that are unsupported by Sonos) to Dolby Digital Plus. This is because DD+ can support up to 6Mbps throughput versus Dolby Digital's 640Kbps cap.

A simple software upgrade would deliver higher audio fidelity to systems with a Sonos Beam in a 5.1 arrangement (i.e. a Beam + 2x Sonos Ones + a SUB).

Note: this request is separate from delivering true home theater Dolby Atmos in a 7.1.4 speaker arrangement.


For more details:

https://developer.dolby.com/blog/dolby-audio-over-hdmi-part-1-codecs/

https://developer.dolby.com/blog/dolby-audio-over-hdmi-part-2-signaling-and-carriage/

https://developer.dolby.com/blog/dolby-audio-over-hdmi-part-3-reality/

https://developer.dolby.com/blog/dolby-audio-support-on-apple-tv/

https://www.avsforum.com/forum/39-networking-media-servers-content-streaming/2378442-dolby-digital-plus-dd-atmos-over-hdmi-arc.html

https://en.wikipedia.org/wiki/Dolby_Laboratories

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34 replies

Userlevel 1
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Jesus. I build this for 25 years and here you come now.

. Learn how to read the spec properly. Its there. Heres a neat picture for you.


Moderator note: Edited for profanity.
Userlevel 2
Jesus. I build this for 25 years and here you come now. Learn how to read the spec properly. Its there. Heres a neat picture for you.
First of all that isn't from the official HDMI 1.4 specification document. I've seen that pretty picture you've posted but it doesn't explain how manufacturers of televisions do have some models that are known to pass DD+ signals through ARC. I understand the physical limitations and hardware designed limitations imposed on the digital audio out connectors. As HDMI cables are not the same medium nor does the ARC have to receive the same output signal as traditional SPDIF outputs, I'm trying to understand how manufacturers are allowing some DD+ over ARC. I struggle with how Common mode on ARC can eek out a bit more bandwidth, if that is how manufacturers are doing it. I don't deny there is some limitation which necessitates the creation of eARC but DD+ is rather broad in it's capabilities. I honestly don't expect an answer and I'm okay with that.
The way you respond to people trying to gather additional knowledge over how some things work is keeping me from thinking you are a helpful source, "sparky". You might consider toning down your responses if you want to be taken seriously as opposed to your my way or the highway approach. Sorry to have bothered you.
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Jesus. I build this for 25 years and here you come now. Learn how to read the spec properly. Its there. Heres a neat picture for you.First of all that isn't from the official HDMI 1.4 specification document. I've seen that pretty picture you've posted but it doesn't explain how manufacturers of televisions do have some models that are known to pass DD+ signals through ARC. I understand the physical limitations and hardware designed limitations imposed on the digital audio out connectors. As HDMI cables are not the same medium nor does the ARC have to receive the same output signal as traditional SPDIF outputs, I'm trying to understand how manufacturers are allowing some DD+ over ARC. I struggle with how Common mode on ARC can eek out a bit more bandwidth, if that is how manufacturers are doing it. I don't deny there is some limitation which necessitates the creation of eARC but DD+ is rather broad in it's capabilities. I honestly don't expect an answer and I'm okay with that.
The way you respond to people trying to gather additional knowledge over how some things work is keeping me from thinking you are a helpful source, "sparky". You might consider toning down your responses if you want to be taken seriously as opposed to your my way or the highway approach. Sorry to have bothered you.


First off. This thread was about enabling Dolby Digital Plus on Sonos products. I said you cant on any current hardware they make. I was challenged and told that wasnt true by someone who literally has zero clue and demonstrated so by stating factually incorrect statements about the technology as a whole, much less these products. All by someone who thinks they are smart about it. I elaborated. The more he replied the more nonsensical and laughable it became.

Yuk yuk wasnt trying to gain knowledge, he was trying to be right. He was citing things as fact that werent as if he was qualified to make the statements, from the hardware capabilities in the processors down to the functions of ARC. He wanted everyone to believe he could hear significant difference with a 3" driver smothered in processing sauce using a codec with marginal improvements at low bitrates. It's laughable and any EE or acoustical engineer will tell you the same thing.

You challenged the fact that ARC is limited to 1Mbps in doing so. That's the max for an audio payload. Period. Then you want to talk about the spec, and infer you have an understanding of it because you cant "find" where it says to you in plain English the limitation of ARC. There are many more layers involved beyond the 1.4 spec in this equation.

So, for the layman, I posted a neat little picture that shows you the bitrate capabilities across the signals. And now you complain about it. I'm not here to educate you. You jumped in and challenged what I said. I responded as it's another case of someone throwing data around they dont have any experience nor qualification to be positioning themselves behind, and doing so erroneously.

I'll say it again. If you are going to try and throw the spec out and sound smart about it, know the spec and everything in it, both literally and relative to it before trying to use it in your arguments. Learn how to read it. Understand it. It's obvious you don't. I can explain it to you, but I can't understand it for you.

DD+ has been around now over 10 years. ARC has been around 10 years. Isn't a bit obvious as to why you dont find widespread support of it 10 years down the road? I dont expect an answer, but you should really think about that one for a minute. Might it be because there's marginal value vs cost and the fact that DD+ with it's legs cut off is not how Dolby wants the ecosystem? Hmmmm.....The way you answer is keeping me from thinking you're helping yourself. Im not trying to help you, I'm responding to fairy tales and pixie dust sprinkled around as if they are fact from people who suffer from the Dunning Kruger effect.
Userlevel 2
Yuk yuk wasnt trying to gain knowledge, he was trying to be right.
Your need to belittle people is astounding.

He was citing things as fact that werent as if he was qualified to make the statements, from the hardware capabilities in the processors down to the functions of ARC. He wanted everyone to believe he could hear significant difference with a 3" driver smothered in processing sauce using a codec with marginal improvements at low bitrates. It's laughable and any EE or acoustical engineer will tell you the same thing.
I think people just want to know why Sonos would develop a new product that is marketed as being expandable to fill your room with sound and where the onus really is on the source device or even the television to properly extract the 5.1 substream out of DD+ to get the Beam what it wants. Unfortunately, cost saving measures by the developers of these systems don't always make that a reality, and backward support is often a thing of the past as making something future-proof doesn't bring in new revenue.

Now to you...

You decided to step on the dance floor like a scorned housewife asking me if I "cared to" back up my words and you challenged the fact that ARC is limited to 1Mbps in doing so. Now you want to cry about tone of verbage? Don't be so sensitive sweetheart.

There's that belittling behavior again, and trying to emasculate by using demeaning feminine phrases rather than just having a civil discussion. I think there are more productive ways of getting a point across, but to each their own.

Then you want to talk about the spec, and infer you have an understanding of it because you cant "find" where it says to you in plain English the limitation of ARC. There are many more layers involved beyond the 1.4 spec in this equation.
Of course there are, like IEC 60958-3 and IEC 61937, as well as the signaling technology being used to put that data on the line. Given I'm not an adopter of HDMI technologies, I haven't personally had a chance to see a full specification document for HDMI 2.1. I'd be very interested to see how they are handling the higher bandwidth of these advanced audio formats via eARC as it relates to the older 1.4 ARC specification. I'm guessing it has more to do with the Audio Return Channel receiver and transmitter functions in hardware and the signaling technology and little to do with the cable itself, as currently existing Standard HDMI with Ethernet and High Speed HDMI with Ethernet cables can and will support eARC, even if they don't support some of the other features coming with HDMI 2.1. Same cables that are used today that are limited by the 1.4 spec bandwidth will be able to handle higher bandwidth audio for eARC in 2.1.


I'm not here to educate you.Clearly.


I'll say it again. If you are going to try and throw the spec out and sound smart about it, know the spec and everything in it, both literally and relative to it before trying to use it in your arguments. Learn how to read it. Understand it. It's obvious you don't. I can explain it to you, but I can't understand it for you.You can refrain from trying to explain. I prefer to learn from people that have a passion for passing on knowledge rather than those who lord their knowledge or expertise in their chosen field over others, and basically see other people as less than them.I'm responding to fairy tales and pixie dust sprinkled around as if they are fact from people who suffer from the Dunning Kruger effect.I know my limitations with respect to this topic. I'm not an expert in it, but I can recognize that and still partake in discussions to learn more. That doesn't really fit your cognitive bias labeling, but I'm sure you meant it again as a way to belittle us. Who uses that specific terminology unless they've used it once or twice or likely several times before?!

All I have to say is I can't wait to get a new television that does a better job of handling DD+ and can push a DD stream to my Beam. I hate spending money on technology that obsoletes itself from year to year. I also don't want to keep trashing/selling/storing TVs to keep up with the latest greatest.

Oh and for those who care, I found this an interesting article that would in fact show that manufactures have in fact the capabilities through hardware to send higher bitrate material over ARC (specifically LG and Samsung from this article), and that many manufactures had looked to the future and will be able to provide some potential firmware updates to some of their hardware to support eARC when it becomes official, meaning that ARC port will become so much more.
http://www.bluedotmagazine.com/2018/10/31/more-and-more-manufacturers-unlock-hdmi-audio-return-channel/[/quote]
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Yuk yuk wasnt trying to gain knowledge, he was trying to be right.


Your need to belittle people is astounding.

 

 

 

He was citing things as fact that werent as if he was qualified to make the statements, from the hardware capabilities in the processors down to the functions of ARC. He wanted everyone to believe he could hear significant difference with a 3" driver smothered in processing sauce using a codec with marginal improvements at low bitrates. It's laughable and any EE or acoustical engineer will tell you the same thing.

 


I think people just want to know why Sonos would develop a new product that is marketed as being expandable to fill your room with sound and where the onus really is on the source device or even the television to properly extract the 5.1 substream out of DD+ to get the Beam what it wants. Unfortunately, cost saving measures by the developers of these systems don't always make that a reality, and backward support is often a thing of the past as making something future-proof doesn't bring in new revenue.

 

 

 

 

Now to you...

You decided to step on the dance floor like a scorned housewife asking me if I "cared to" back up my words and you challenged the fact that ARC is limited to 1Mbps in doing so. Now you want to cry about tone of verbage? Don't be so sensitive sweetheart.

 


There's that belittling behavior again, and trying to emasculate by using demeaning feminine phrases rather than just having a civil discussion. I think there are more productive ways of getting a point across, but to each their own.

 

 

 

 

Then you want to talk about the spec, and infer you have an understanding of it because you cant "find" where it says to you in plain English the limitation of ARC. There are many more layers involved beyond the 1.4 spec in this equation.

 


Of course there are, like IEC 60958-3 and IEC 61937, as well as the signaling technology being used to put that data on the line. Given I'm not an adopter of HDMI technologies, I haven't personally had a chance to see a full specification document for HDMI 2.1. I'd be very interested to see how they are handling the higher bandwidth of these advanced audio formats via eARC as it relates to the older 1.4 ARC specification. I'm guessing it has more to do with the Audio Return Channel receiver and transmitter functions in hardware and the signaling technology and little to do with the cable itself, as currently existing Standard HDMI with Ethernet and High Speed HDMI with Ethernet cables can and will support eARC, even if they don't support some of the other features coming with HDMI 2.1. Same cables that are used today that are limited by the 1.4 spec bandwidth will be able to handle higher bandwidth audio for eARC in 2.1.

 

 

 

 

I'm not here to educate you.

 


Clearly.

 

 

 

 

I'll say it again. If you are going to try and throw the spec out and sound smart about it, know the spec and everything in it, both literally and relative to it before trying to use it in your arguments. Learn how to read it. Understand it. It's obvious you don't. I can explain it to you, but I can't understand it for you.

 


You can refrain from trying to explain. I prefer to learn from people that have a passion for passing on knowledge rather than those who lord their knowledge or expertise in their chosen field over others, and basically see other people as less than them.

 

I'm responding to fairy tales and pixie dust sprinkled around as if they are fact from people who suffer from the Dunning Kruger effect.

I know my limitations with respect to this topic. I'm not an expert in it, but I can recognize that and still partake in discussions to learn more. That doesn't really fit your cognitive bias labeling, but I'm sure you meant it again as a way to belittle us. Who uses that specific terminology unless they've used it once or twice or likely several times before?!

All I have to say is I can't wait to get a new television that does a better job of handling DD+ and can push a DD stream to my Beam. I hate spending money on technology that obsoletes itself from year to year. I also don't want to keep trashing/selling/storing TVs to keep up with the latest greatest.

Oh and for those who care, I found this an interesting article that would in fact show that manufactures have in fact the capabilities through hardware to send higher bitrate material over ARC (specifically LG and Samsung from this article), and that many manufactures had looked to the future and will be able to provide some potential firmware updates to some of their hardware to support eARC when it becomes official, meaning that ARC port will become so much more.
http://www.bluedotmagazine.com/2018/10/31/more-and-more-manufacturers-unlock-hdmi-audio-return-channel/

 


http://community.cedia.net/blogs/david-meyer/2018/06/25/dolby-atmos-over-hdmi-arc

"So existing HDMI ARC can potentially support Dolby Atmos by maxing out the Common mode capability with an MAT stream. But there's a huge catch. Two, actually;

Channel count & resolution — while E-AC-3 can support up to 15.1 channels of audio, it's well beyond the HDMI ARC spec. Even getting 7.1 channels to pass is a stretch, so even if the stream contains object metadata, it will lack the resolution and height speakers.
System support — getting Atmos to work through HDMI ARC requires Common mode support in both the TV and AVR, and a high integrity link in-between. Even then, performance will be marginal.

HDMI 2.1 will change things considerably. It introduces enhanced ARC"
 

*Moderator Note: Modified in accordance with the community guidelines.*

 

Userlevel 2
More vitriol. Not surprised. Whining? Don't recall doing that but I'm only assuming you think I am seeking your validation or acceptance which is far from the truth. I already read the article you linked and the reason I was more interested in understanding common mode within ARC. Thanks. Try having a conversation instead of seeing everything as an argument.

Just stumbled upon this thread while considering Sonos as a 5.1 solution rather than installing dedicated speaker cabling in a room.

ARC has two operating modes. Single Mode and Common. There are suggestions single mode supports up to 3Mbps, but I believe the bandwidth is very dependent on cable length so likely the 1Mbps measure mentioned is a safe compromise that allows it to work consistently. Common mode can support up to 12Mbps and would therefore be ample to support Dolby Digital+. The problem is that both the sender and receiver have to support Common mode and with most manufacturers not even stating whether they support Common mode - it seems unlikely to gain significant traction. LG do support it, and apparently even support a compromised Dolby Atmos over it.

For me the Sonos brand wants to be like Apple where 'stuff just works' (even if that is more marketing than reality!). Adding DD+ using Common mode would likely result in a hit and miss experience for customers, damaging the perception of 'stuff just works'.

I can't believe Sonos want to get into the space of some of the other soundbar manufacturers where they are taking full HDMI video feeds, stripping the audio and then passing the video on to the TV and even if they did, they'd need new hardware to do that.

Much more likely is a replacement Playbar with eARC sometime in the future.

This article gives a pretty good understanding of the challenge here if you want to draw your own conclusions:
http://community.cedia.net/blogs/david-meyer/2018/06/25/dolby-atmos-over-hdmi-arc

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HDMI ARC can and in many implementations DOES DD+.

Atmos was originally encoded in TrueHD (lossless) codec, but there are implementations (like Netflix) that use DD+ to carry Atmos soundtracks in a lossy codec.

A good thread to read:
https://www.avsforum.com/forum/39-networking-media-servers-content-streaming/2378442-dolby-digital-plus-dd-atmos-over-hdmi-arc.html

However, we're not talking Atmos, but DD+ in "regular 5.1". Yes, ARC supports DD+.

Would I love it if Sonos implemented it on the Beam? Damn right I would!

Do I know if the hardware is the limitation? No. I have no idea what HW is under the hood, and if it can be upgrade to support DD+. If you know what HW is there, please do share, along with proper specifications.
I think the best solution to this request is make a teardown of the Sonos Beam ,and see what DSP ic they are using and from there you will know it can be implemented with a software update.