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

DD+ or E-AC3 is a published format (Annex E of ATSC A/52:2012). FFMPEG produces compliant E-AC3 encodes (currently limited to 5.1 channels with no Atmos object transcoding). A number of apps with millions of users (Plex, Kodi, Infuse, MrMC, etc.) leverage FFMPEG. For example, Plex transcodes lossless audio to E-AC3 by default. That is why I used it for testing. As discussed earlier, Dolby's encoder is reportedly best of breed.

I transcoded a number of audio segments to E-AC3. To my ears, E-AC3--somewhere between 2.5-3Mbps--is perceptually transparent to lossless audio tracks such as LPCM, TrueHD or DTS-HD Master Audio (depending on the audio segment). We await your test results.

You continually say that ARC is limited to 1Mbps while DD+ tops at 6Mbps. But, your assessment necessarily is based on a 48 kHz clock rate (which is closer to 1.5Mbps). To reaffirm my earlier math: at a 192 kHz clock rate, you get 6.1 Mbps. Moreover, all the major CE manufacturers (e.g. Samsung, LG, Sony, etc.) have Dolby Atmos soundbars that support E-AC3 over ARC. So, it's not clear why you are arguing against the possiblity of E-AC3 over ARC.

I don't have the time or desire to deconstruct my new Sonos Beams but there are publicly available teardowns of the Sonos One. These report that the SoC is a Freescale NXP SoM SC667517EYM10AE. This is more than capable of decoding E-AC3. See: https://medium.com/@BenEinstein/what-cracking-open-a-sonos-one-tells-us-about-the-sonos-ipo-dcab49155643
I would be surprised if the Sonos Beam is significantly different from the Sonos One, architecturally.

Sonos couldn't do this in earlier iterations of their speakers because:
(1) the Playbar and Playbase were limited to an optical audio connection (not HDMI ARC), and
(2) the earlier generation of Sonos speakers had processors that were, by Sonos' reporting, 1/16 as powerful as current generation of speakers.

Addressing what the advantage of eARC over ARC is:
* support for lossless codecs like TrueHD or Dolby MAT 2.0 up to 38 Mbps, and
* there is also better service discovery and better lip sync.

Finally, my goal is to improve Sonos' Beam/AMP/One product lines. I have invested $$,$$$ in my Sonos equipment. My focus is improving the sound quality for the systems that I have purchased. I commend how Sonos has continued to improve Sonos spears that are 10-15 years old.

What is your Sonos $ investment and objectives?

Dear lord. Enjoy your Sonos. You really have no clue what you're talking about and make an astronomical amount of assumptions as it relates to the topic. Peace out.

🆒 ARC= 1Mbps. Don't forget.

Rut roh....

along with the Keyword

You should have noticed these when you were cutting and pasting "your math" from the Dolby dev site.

Since you don't have access to the same Dolby information as us engineers who do this for a living do.....

And since you like being links and are clearly an educated audiophile: https://www.nakamichi-usa.com/best-dolby-atmos

Atmos = TrueHD or DD, in case you forgot.

Might give you a clue about a few other things if that doesnt make it obvious for you.

I'm sure the actual investors (as in the stockholders) are quite excited at the proposition that you will need to invest further in order to realize your feature addition dreams. Nite nite.

n re: ARC/DD+, good luck. I'd love to see what an HDMI analyzer tells you that you are actually getting in that DD+ stream. You might be a bit surprised. I'll tell you this juicy lil tidbit, it's obvious you didn't know that the ARC bitrate is capped at 1Mbps, which is a VERY low bitrate DD+ stream. DD+ reaches 6Mbps, and as such ARC DOES NOT SUPPORT IT...you're getting a marginally better stream than legacy DD encoded a bit more efficiently to the extent it can with any additional allocated bits (which isnt a whole lot down that low). So if you want to claim it's supported because it will give you a stream with a DD+ EDID report that is literally encoded slightly more efficiently with an additional 360Kbps across 6 channels of audio vs. legacy DD, feel free to kid yourself (which isn't even what occurs with the additional bitrate anyways in a literal sense). But hey, if you can hear the sub 1Mbps efficiency improvement to the compression schema via an ARC connection on a 3" driver ...I'd love to hire you to come in and work on my staff as none of my 30 year acoustical engineers can do it, nor can an analyzer. When you learn how those extra bits are allocated, you'll probably feel sillier, but I'll just stop there.

So, you can convince yourself that you can hear 360Kbps of glorious audio bliss and massive improvement between DD and DD+ all you want, but the way the compression scheme works and bitstream is handled, it's pretty funny to see you try. But you do you boo. WIth 93% of the panels in the market not supporting DD+ via ARC and a fraction of AVR's out there doing it, you get 3 flavors chief...DD, DTS 5.1 and Stereo PCM ..and if you're foolish enough to think that DD+ is going to matter...well, can't help you chief. 😃
Care to provide since factual references to your claims? Where within the HDMI 1.4 specifications does it state ARC is capped at 1Mbps? I'm struggling to find the evidence for the physical limitation of the HDMI hardware that would prevent this or prove this.. It's troubling given reports by several people of their newer TVs handling some forms of DD+ over ARC which would imply that to some extent it is possible.

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.

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.

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]