Sukh0000007

Active Member
Hi

Hope you're all well.

I'm aware tv apps such as Disney and Netflix can only play Atmos via DD+ pass through, however, when playing content from Disney through my TV alone (LG Nano90 2021), both Dolby Vision and Dolby Atmos logos appear in the top right corner of my TV. The TV is atmos, but obviously not playing Atmos sound.

But when I switch on my Yamaha RXV6A, connected via HDMI 2.0 ARC, and playing the same content on Disney, only the Dolby Vision logo appears, and not the Dolby Atmos. And on my AV screen, it shows as only DD+, not Atmos.

I have 5.1.2 set up. Is something missing?
 

dante01

Distinguished Member
The logo doesn't appear on the TV because the TV isn't dealing with the audio. The audio is being output via ARC to the AV receiver. Look on the AV receiver to determine what the audio format is if using the AV receiver to process the audio.

The Audio you are getting should be DD+ inclusive of Atmos metadata. THere are certain circumstances that would result in youyr AV receiver ignoring the Atmos metadata. Don't engage any upmixing apart from Dolby Surround upmixing or any of the DSP Programs on the AV receiver. additional height soeakers.

There's technically no reason why your AV receiver wouldn't be able to access Atmos if and when sourced via the apps on your TV and when conveyed to the AV receiver via ARC.
 
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dante01

Distinguished Member
Is the issue resolved?


Even though the Atmos metadata is packaged with the DD+ encoded audio, the AV receiver should still indicate if and when it is receiving Atmos on its display. Is this the case?
 

Sukh0000007

Active Member
Hi

That's what I meant, it doesn't show

"DD+ Atmos" on the reciever screen.

It was doing so before. But not anymore. So thought I got something wrong
 

dante01

Distinguished Member
THere should be a Dolby Demo app on LG TVs that includes content encoded with Atmos. TRy that and see if the receiver picks up the oresence of Atmos?

Also engage the STAIGHT mode on the AV receiver to eliminate any additional processing that may be causing the issue you are having?


TRy setting the digital audio output on the TV in association with ARC to PASS THROUGH or AUTO depending upon how it is already configured. Maybe even go as far as powering doiwn both the TV and AVR into standby and then disconnecting the cable between them to enable you to then reconnect and reseat it. Also try toggling the HDMI Control setting onboard the AV receiver to try restablish a new HDMI handshake between the 2 devices?
 

Sukh0000007

Active Member
Hi

I've done this, set the arc on TV to Auto.

It shows at "Atmos/PCM" on the av receiver screen now.

Is that correct?
 

dante01

Distinguished Member
Hi

I've done this, set the arc on TV to Auto.

It shows at "Atmos/PCM" on the av receiver screen now.

Is that correct?

Are you passing the audio through the TV from an Apple TV or PC connected to one of the TV's other HDMI inputs?

You'd only get Atmos with PCM if using Dolby MAT and the only devices to use Dolby MAT to output Atmos in conjuction with multichannel PCM are the Apple TV 4K, XBoxes and Windows PCs.

You'd more ordinarilly get DD+ in association with Atmos if accessing it via the streaming apps inboard the TV itself.
 

Sukh0000007

Active Member
Hi

I set the arc to auto on the TV. And I'm streaming Disney on my TV, atmos content.

If I set to pass through then it shows as "DD+" on my reciever. If I set to Auto and it shows as "Atmos/PCM".
 

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dante01

Distinguished Member
Strange.

Netflix, Amazon Disney+ and Apple all encode their audio as DD+ and this would ordinarily be what they package Atmos metadata with. THis is also what would ordinarilly be output via ARC if accessing Atmos via the apps on a TV.

Not at all sure why your are getting Atmos in association with PCM?


Here's what I get via Disney+ access via the app onboard my LG C9 and output using ARC to my Yamaha RX-A1080:

by default 2021-10-15 at 22.33.35.png



The only time that you expect Atmos metadata to be conveyed with multichannel PCM is if accessing Atmos via an XBox, an Apple TV or a Windows PC.
 

Sukh0000007

Active Member
That's what I got when I first set up my Rxv6a! "atmos/dd+"

But I get the below meassges now.

Still sounds amazing with DD+, with QAcoutics and PB2000 Sub.

But I have in-ceiling Polk audio speakers, and I bought the RXV6A especially for atmos.

Upsetting
 

dante01

Distinguished Member
Am i correct in thinking that the Atmos embedded in DD+ is compressed version of Atmos only ? thx


Atmos is simply metadata. The audio element is the DD+ encoded audio and this denotes the quality of theaudio being portray whether just the DD+ with or without the Atmos metadata being read by the AV receiver. Yes, DD+ is a lossy compressed audio format with a lower bitrate than an HD format such as TrueHDm but still higher than that associated with conventional Dolby Digital.

Atmos itself doesn't denote the quality or definition of the audio. It is the TrueHD or the DD+ audio it is packaged with that determines the quality and definition.


Dolby Atmos in Dolby TrueHD
Dolby has expanded the Dolby TrueHD format to allow the format to support Dolby Atmos content on Blu-ray and ultra high definition Blu-ray Disc. Prior to Dolby Atmos, Dolby TrueHD provided lossless support for channel-based audio, such as 5.1 and 7.1. Now we have added a fourth substream for Dolby Atmos sound in Dolby TrueHD codec to enable a support for a losslessly encoded object-based sound mix.
Dolby Atmos in Dolby TrueHD is transmitted from a Blu-ray player or Ultra HD Blu-ray player to your AVR via an HDMI connection. If your AVR supports Dolby Atmos, the Dolby TrueHD object-based audio and related metadata will be decoded, processed, scaled, and rendered to your specific speaker configuration. Dolby Atmos audio can be encoded with Dolby TrueHD at multiple sampling rates (including 48 and 96 kHz) and bit depths (16- and 24-bit).
Dolby Atmos enabled receivers will also support legacy Dolby TrueHD bitstreams at multiple sampling rates (including 48, 96, and 192 kHz) and bit depths (16-, 20-, and 24-bit) to provide full backward compatibility with legacy Blu-ray Disc media and Dolby TrueHD music files.

Dolby Atmos in Dolby Digital Plus
Dolby Digital Plus has been updated and features a new decoder capable of processing content encoded for Dolby Atmos. This module uses new bitstream metadata to extract Dolby Atmos object-based audio and outputs this information for further signal processing. The sampling rate for Dolby Atmos content is 48 kHz, the same sample rate as for Dolby Digital Pluscontent.
Both new audio decoders are designed to be fully backward compatible with legacy channel-based Dolby Digital Plus and Dolby TrueHD soundtracks.

Dolby Atmos in Dolby MAT
The Dolby Metadata-enhanced Audio Transmission (Dolby MAT) encoder resides in a Blu-ray player to pack the variable bit-rate Dolby TrueHD bitstreams for transmission over the fixed bit-rate HDMI connections. A MAT decoder is subsequently employed in an AVR to unpack the Dolby TrueHD bitstreams. With the introduction of Dolby Atmos, we have expanded this technology to support encoding of Dolby Atmos content as lossless pulse-code modulation (PCM) audio
A key benefit of Dolby MAT 2.0 is that Dolby Atmos object-based audio can be live encoded and transmitted from a source device with limited latency and processing complexity. Among the possible sources are broadcast set-top boxes, PCs, and game consoles. The Dolby MAT 2.0 decoder in an AVR outputs the object-based audio and its metadata for further processing. The Dolby MAT 2.0 container is scalable and leverages the full potential of the HDMI audio pipeline.




Initial Dolby Atmos content for home theaters was delivered via Blu-ray Disc and streaming video via over-the-top (OTT) services. For Blu-ray and Ultra HD Blu ray, studios will employ lossless Dolby TrueHD for the primary soundtrack and Dolby Digital Plus for secondary languages. OTT streaming services and cable services are supported by Dolby Digital Plus. In the future, Dolby Atmos content will be delivered via video on demand (VOD) and broadcast (terrestrial and digital) that use multichannel Dolby Digital Plus in their core architecture. Dolby Atmos can also be supported in video game soundtracks and delivered to the AVR for decoding and processing via Dolby MAT.
 
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dante01

Distinguished Member
That's what I got when I first set up my Rxv6a! "atmos/dd+"

But I get the below meassges now.

Still sounds amazing with DD+, with QAcoutics and PB2000 Sub.

But I have in-ceiling Polk audio speakers, and I bought the RXV6A especially for atmos.

Upsetting


I'd continue with the Atmos/PCM stream if it is giving tou Atmos and engaging the ceiling speakers. It is derrived from the DD+ audio regardless of whether or not the AV receiver is indicating that the Atmos metadata is being conveyed with DD+ or with PCM. THe audio quality would be exactky the same either way.

No idea as to why the setup you have would result in the Atmos metadata being output from the TV in conjunction with PCM though?
 

Daytrader

Well-known Member
Atmos is simply metadata. The audio element is the DD+ encoded audio and this denotes the quality of theaudio being portray whether just the DD+ with or without the Atmos metadata being read by the AV receiver. Yes, DD+ is a lossy compressed audio format with a lower bitrate than an HD format such as TrueHDm but still higher than that associated with conventional Dolby Digital.

Atmos itself doesn't denoye the quality or definition of the audio. It is the TRueHD or the DD+ audio it is packaged with that determines the quality and definition.
Ah i see, thx for all that info, cheers
 

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