Originally Posted by scarabaeus
DD+ can carry Dolby Atmos from smart TV apps to an AVR or Soundbar. So far, few TVs support this feature.
There is a lot of misinformation about this topic, and I'm moving a recent discussion here from the Vizio 2016 P Series thread, because it was getting too off topic there.
The technical basics: Dolby Digital Plus (technical term: E-AC-3) is an IEC-61937 audio format with a frame rate of 192 kHz, as opposed to the older Dolby Digital (AC-3), which has an IEC frame rate of 48 kHz. DD can carry channel based audio with up to 5.1 channels, while DD+ can carry up to 7.1 channel based, as well as Dolby Atmos object based audio.
IEC based interfaces in consumer devices are SPDIF (on both RCA and optical connectors) and HDMI ARC. The latter is an audio connection from an HDMI input (e.g. on a TV) to an HDMI output (e.g. on an AVR). It travels the opposite direction from the normal HDMI video/audio connection, hence the name "Audio Return Channel".
HDMI ARC has capability negotiation, using HDMI CEC messages, while SPDIF does not. This means, an ARC source (TV) can determine which audio formats are understood by the ARC receiver (AVR, Soundbar), while an SPDIF source can just try and send stuff and hope for the best. Mainly for this reason, SPDIF is usually limited to the 48 kHz realm (DD, DTS and stereo PCM), and often can not support the 96 and 192 kHz formats (96 kHz PCM, DD+, DTS-HD High Resolution). Cables and connectors are another limiting factor, often not supporting the frequency range for 192 kHz.
ARC is mainly used when an AVR or an HDMI connected Soundbar are used with a TV. Audio that originates from the TV, such as from the tuner, from OTT ("Over The Top") apps like Netflix, Amazon, Vudu, etc., or even from other HDMI inputs to the TV, can be sent to the sound device without the need for an extra cable.
Many TVs have both an SPDIF output as well as ARC on one of the HDMI inputs. This gives users the option to use SPDIF or ARC.
Now, this was all fine and dandy while there was only 48 kHz audio. TVs were built with chips that had just one audio output, and that audio was sent to SPDIF and ARC at the same time. But now there is Atmos. BD and UHD Blu-ray, Vudu UHD streams, and other sort of "premium" content comes with "premium" immersive audio, mostly Atmos. A lot of TV maker did not prepare for that, and are still downgrading DD+ content to DD before sending it out on ARC. So, we get plain 2.0 or 5.1 with the spiffy new UHD HDR 4K video.
Slowly TVs are starting to support this, in particular Dolby Vision TVs (though not all of the initial ones). I'll work on maintaining a list of TVs, AVRs and Soundbars that support DD+ over ARC, since this information is often hard to find. If you encounter a device, let me know and I'll add it to the lists.
Please find the lists below.
I just randomly ran across this thread, but I'm very happy to see it. I got tired of arguing with people that I was getting an Atmos signal from my P75-c1 via ARC while casting Vudu and Netflix to my set.
I bought a new house 4 months ago, and I've spent the last 4 months remodeling (that's another story), but I was very disappointed to find out that I couldn't use an Atmos setup in my living room. The only room in my house that I was able to setup a 7.1.4 system was in the media room upstairs, and I had my Vizio P75-c1 installed in this room for this particular reason. I would have loved to have an Atmos setup in my living room, where my new LG W7 is setup, but I don't want to have free standing speakers visible around the room. I sold all my free standing speakers and now have a 7.1.4 setup using all in-wall/on-wall/in-ceiling speakers in my media room. The installers have been installing my AV system for 4 months now and are almost finished, and I'm literally dying to start watching movies again. I'm sure I'll be spending the majority of this weekend updating firmware on every component I have, then I can start to enjoy my new house.
Again, thank you for starting this thread, even though I see it was started over a year ago, but it's been a busy year, and I haven't spent as much time on this forum as I used to. From what I've read recently, I believe an updated version of ARC is in the works (ARCe or eARC, I forgot), but this newer version should make this possible for every device to output Atmos via ARC. I guess I got lucky with my Vizio, which was the first HDR set I bought. Now, every TV in my house is 4K HDR, and all of them are setup on an A/V matrix. Now, at least I have a good resource to go to whenever I want to upgrade my Vizio P75-c1. Thanks again (belated) for this thread!