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User profile for user: Runpaulrun
Runpaulrun Author
User level: Level 1
5 points

Apple TV 4k Setup Question

I have a home theater setup and a question about audio:

ATV4k -> Denon x3700h -> 5.1 speakers


The goal is highest quality 5.1 surround sound. I'd prefer to have the Denon AVR decode the audio but if that's not possible it's ok to have the ATV4k do it. I want to avoid at all costs audio upscaling and compression. The AVR is set to auto detect the input format.


When audio format is set to "Off" the ATV4k message implies it will sense the format and send the maximum quality audio via LPCM. The AVR input says "Multi Channel Input" which means it (the AVR) has no influence on the audio.


When the audio format is set to "Dolby 5.1" the Apple TV 4k message suggests poor quality audio. The AVR input says "Dolby DD +DSur".


My questions:


Is there a way to see what format ATV4k sensed and is sending to the AVR when set to "Off"? At what point is the signal downscaled to 5.1 when necessary (from 7.1, Atmos, etc)?


When the ATV4k is set to "Dolby 5.1" the Dolby DD +Dsur at least indicates it (the AVR) knows the format. What does +DSur suggest? Is the ATV4k sending compressed audio? Will it attempt to upscale a stereo input to 5.1 (do NOT want that)?


What is the best setting for 5.1 surround with no compression or upscaling? Have I interpreted what is happening correctly?


Thanks!

Apple TV 4K

Posted on Mar 17, 2022 7:32 AM

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User profile for user: Urquhart1244
Urquhart1244
Community+ 2024
User level: Level 10
142,992 points

Posted on Mar 17, 2022 1:52 PM

Is there a way to see what format ATV4k sensed and is sending to the AVR when set to "Off"? At what point is the signal downscaled to 5.1 when necessary (from 7.1, Atmos, etc)?

With Audio Format ‘Auto’ (Change format off), Apple TV will send out PCM Multichannel for audio, as decoded from the incoming stream from the internet (Dolby Digital or AAC, most likely). Conversion to PCM is lossless for quality. PCM is uncompressed.

The Apple TV box will request a stream with the matching audio channels, so that downmixing or upmixing doesn’t need to happen. Most commercial streams are available for multiple audio formats on the servers.

Dolby Atmos will be send as Dolby MAT (like PCM) (only available if supported),

7.1 will be send as 7.1 PCM,

5.1 will be send as 5.1 PCM,

Stereo will be send as 2.0 PCM,

Mono will be send as 1.0 PCM.


What does +DSur suggest? Is the ATV4k sending compressed audio? Will it attempt to upscale a stereo input to 5.1 (do NOT want that)?

+DSur is a receiver setting to allow for upmixing to the number of speakers available. I.e. a stereo source may be played as 5.1. It is not controlled by the Apple TV box.

What does "+Dsur" on my receiver actually mean? - Reddit


What is the best setting for 5.1 surround with no compression or upscaling? Have I interpreted what is happening correctly?

‘Auto’ (Change format off) is the best setting if fully functional with your equipment. The Dolby Digital 5.1 format setting is a fallback option for equipment that can’t handle PCM Multichannel. The Dolby Digital 5.1 format will convert and compress (as Dolby Digital is always compressed, unlike PCM).

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User profile for user: Urquhart1244
Urquhart1244
Community+ 2024
User level: Level 10
142,992 points

Mar 17, 2022 1:52 PM in response to Runpaulrun

Is there a way to see what format ATV4k sensed and is sending to the AVR when set to "Off"? At what point is the signal downscaled to 5.1 when necessary (from 7.1, Atmos, etc)?

With Audio Format ‘Auto’ (Change format off), Apple TV will send out PCM Multichannel for audio, as decoded from the incoming stream from the internet (Dolby Digital or AAC, most likely). Conversion to PCM is lossless for quality. PCM is uncompressed.

The Apple TV box will request a stream with the matching audio channels, so that downmixing or upmixing doesn’t need to happen. Most commercial streams are available for multiple audio formats on the servers.

Dolby Atmos will be send as Dolby MAT (like PCM) (only available if supported),

7.1 will be send as 7.1 PCM,

5.1 will be send as 5.1 PCM,

Stereo will be send as 2.0 PCM,

Mono will be send as 1.0 PCM.


What does +DSur suggest? Is the ATV4k sending compressed audio? Will it attempt to upscale a stereo input to 5.1 (do NOT want that)?

+DSur is a receiver setting to allow for upmixing to the number of speakers available. I.e. a stereo source may be played as 5.1. It is not controlled by the Apple TV box.

What does "+Dsur" on my receiver actually mean? - Reddit


What is the best setting for 5.1 surround with no compression or upscaling? Have I interpreted what is happening correctly?

‘Auto’ (Change format off) is the best setting if fully functional with your equipment. The Dolby Digital 5.1 format setting is a fallback option for equipment that can’t handle PCM Multichannel. The Dolby Digital 5.1 format will convert and compress (as Dolby Digital is always compressed, unlike PCM).

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Apple TV 4k Setup Question

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