How do Dolby Atmos and DTS:X work on Xbox One? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 27 Old 09-19-2019, 12:19 AM - Thread Starter
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Question Does an Xbox One process Dolby Digital and DTS audio streams from streaming services?

How do Dolby Atmos and DTS:X work on Xbox One? What are the pros and cons of how they are implemented?
I have an Xbox One S, an Onkyo TX-NR787 A/V receiver, and a 5.0 speaker setup. I don't yet own a subwoofer. I don't yet have a 4K UHD TV and so I don't yet have the 4K UHD Netflix tier--just the standard 1080p Netflix tier. I also have Amazon Prime and Hulu, and have some movies in my VUDU library. The Netflix, Amazon Prime Video, and VUDU apps for Xbox One support Dolby Atmos, and Hulu does not (yet). FandangoNow supports DTS, apparently, from what I have read.
What I mainly want to know is, when I stream Dolby Atmos or Dolby Digital+ from any of the streaming services, or stream DTS from FandangoNow, does my Xbox process the audio, or does it bitstream the audio directly to my AVR without applying any processing? The way I understand it, my Xbox One decodes the Dolby Digital or DTS, mixes it with system sounds (so that, for example, Cortana can beep me with reminders while I am watching a movie), and then repackages the final mix as a Dolby Atmos bitstream and streams it to my AVR. I also understand that at some point, DTS:X will become an alternative output format to Dolby Atmos, and if at that time I change my output format to DTS:X, my Xbox One will do everything the same as before, except that it'll package the output as a DTS:X bitstream and stream it to my AVR.
Most importantly, does my AVR receive all of the Dolby and DTS metadata that is in the ORIGINAL Netflix, Amazon, Hulu, and FandangoNow TV show and movie streams? I specifically want to know if the dynamic range control metadata in Dolby Digital streams is preserved or lost. I'm also curious about how the audio object metadata in Dolby Atmos streams is maintained, and how the audio object metadata in DTS:X streams will, when DTS:X support in apps and games is introduced, be maintained.

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post #2 of 27 Old 09-19-2019, 11:43 AM
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This is currently no way for 3rd party app to bitstream any audio. Xbox must process it. In the case Atmos, you need the help of Dolby Atmos app. For DTS:X, you are SOL. Everything else will be decoded into PCM. The only thing truly bitstreams audio is the BluRay app.

I personally won't use any Xbox Ones as streaming media player. They are just horrible.
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post #3 of 27 Old 09-19-2019, 04:37 PM - Thread Starter
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You didn't say anything about how an Xbox One processes audio *after* it decodes it, nor did you say anything about whether it reprocesses it into a NEW mix prior to sending it to an AVR or TV. I've set my Xbox to bitstream audio from apps and games in the Dolby Atmos for Home Theater format, so my AVR *always* says that it is receiving a Dolby Atmos signal, except when I am playing a Blu-ray that doesn't have Atmos, or a DVD.
I assume that since an Xbox One has to provide audio from multiple apps simultaneously (including system sounds), it processes audio from whatever app is running (Netflix, VUDU, a game, etc.)--and if the app is providing a Dolby Digital or a DTS audio stream, then the Xbox decodes it to MPCM--then mixes in system sounds (so that Cortana can remind you to do stuff, and so that if you have people currently in an Xbox Live party, you'll continue to hear them, though I've never been in an Xbox Live party while streaming a TV show or movie), then reprocesses the audio and repackages it in whatever output format the user has selected (in my case, Dolby Atmos), and sends the audio to the receiving audio device (in my case, my AVR).

If the app is providing a Dolby Atmos audio stream, then I have no freaking idea how the Xbox processes it and mixes in sounds from other sources.

What I need to know is whether the metadata in the Dolby and DTS audio streams from 3rd-party apps is preserved or discarded.
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post #4 of 27 Old 09-19-2019, 08:58 PM - Thread Starter
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Here is what I'm trying to do. I'm trying to set up my Xbox and AVR so that the audio volume of all sources--Blu-rays, games, Netflix, Hulu, etc.--is equal, so that I don't have to change the volume when I close one app and open another. Further, I need to know if my Xbox preserves metadata so that my AVR's "Late Night" mode can work. I've heard that Dolby Digital audio tracks can contain metadata that tells AVRs when to increase the volume and when to decrease the volume in order to minimize audio peaks, and that DTS audio tracks don't have this metadata. I need to know if my Xbox One preserves this metadata in streams from Netflix, Hulu, etc. or does it discard this, making "Night Mode" less useful.
I noticed that in my Xbox One's settings --> Disc & Blu-ray --> Blu-ray, there is a menu called "Dolby Digital", and that menu allows me to choose one of three options: dynamic range control off, dynamic range control on, or dynamic range control auto. These are the same three "Night Mode" options that my AVR offers: off, on, and auto.
- Since the menu is named "Dolby Digital", this reinforces the idea that only Dolby Digital tracks support dynamic range control.
- Since this menu is in Settings --> Disc & Blu-ray --> Blu-ray and not in the system-wide audio settings, it suggests that dynamic range control is only available when I play Blu-rays and DVDs. I hope that this is incorrect.
- If I've chosen the option to "let my receiver decode audio", then I suppose that that overrides the dynamic range control setting on the Xbox, and allows my AVR to perform dynamic range control.
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post #5 of 27 Old 09-19-2019, 09:17 PM - Thread Starter
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Does my Xbox One set an equal audio volume level for all apps? It wouldn't apply to the Blu-ray player app if I've selected the option to bitstream that app's audio output directly to my receiver, but it would apply to all other apps, and it would apply to the Blu-ray player app if I've *not* chosen the previously-mentioned option.

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post #6 of 27 Old 09-20-2019, 05:02 AM
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I don't think Xbox do any of that. Once decoded into PCM, all the metadata are throwed away. Even for Atmos, it is using a special Atmos transport protocol that based on PCM, instead of DD+ or TrueHD compressed audio. So, there is no way for you to achieve your audio leveling this way.

BluRay player app is unique in that it is the only app in Xbox that allows true BitStream,e.g. pass the audio to receiver unchanged.

Get a dedicated stream box. Most of them can easily set audio bitstream. There is zero hope for Xbox One to ever get that support.
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post #7 of 27 Old 09-20-2019, 07:57 AM
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I made a couple of screenshots in the main XBox One X Forum which will aid in proving Foxbat121's point. I noticed that while using the Plex Addon for Kodi, although I'm seeing "Direct Play" for both audio and video streams, my AVR will point out the audio stream is Dolby Atmos no matter the format.


If I were to use my Nvidia Shield or Oppo 203 to stream content with Lossless audio, my AVR will display Dolby True HD alongside Dolby Atmos. If the content is lossy, it will say Dolby Digital Plus along with Dolby Atmos, for example.

With the Xbox One, it's just Dolby Atmos alongside Dolby Atmos.

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post #8 of 27 Old 09-20-2019, 10:03 AM - Thread Starter
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Quote:
Originally Posted by Foxbat121 View Post
throwed
🤨

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Originally Posted by Foxbat121 View Post
Even for Atmos, it is using a special Atmos transport protocol that based on PCM, instead of DD+ or TrueHD compressed audio. So, there is no way for you to achieve your audio leveling this way.
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Originally Posted by groove93 View Post
I made a couple of screenshots in the main XBox One X Forum which will aid in proving Foxbat121's point. I noticed that while using the Plex Addon for Kodi, although I'm seeing "Direct Play" for both audio and video streams, my AVR will point out the audio stream is Dolby Atmos no matter the format.

If I were to use my Nvidia Shield or Oppo 203 to stream content with Lossless audio, my AVR will display Dolby True HD alongside Dolby Atmos. If the content is lossy, it will say Dolby Digital Plus along with Dolby Atmos, for example.

With the Xbox One, it's just Dolby Atmos alongside Dolby Atmos.
But I've only had my current AVR for a few weeks; before it, I was using an AVR that did not have HDMI, and whose best audio ports were optical, and I had my Xbox One S connected via optical cable, and set to bitstream over optical in Dolby Digital. It was sending my AVR a *PROPER* AC-3 signal; if it wasn't, that AVR wouldn't have been able to decode it. So if it was doing that, why wouldn't it be sending my current AVR a *PROPER* Dolby Atmos signal (via Dolby TrueHD) over HDMI? So I doubt what you guys are saying, for that reason, but I would like to see the screenshots that groove93 made.

Side note: another option that I tried when I had my Xbox connected over optical, was to bitstream DTS core. I left my Xbox set to bitstream AC-3 over optical because I noticed that there was distortion or clipping when it was bitstreaming DTS core over optical, and I don't know whether the Xbox or my AVR was the culprit, but my point is that Xbox Ones are able to create a Dolby AC-3 or a DTS core stream on-the-fly and send it to the users' AVRs over optical or HDMI, and they are able to create Dolby TrueHD or DTS HD-MA streams on-the-fly and send it to the users' audio equipment via HDMI. So, I doubt that it would deliver Dolby Atmos via MPCM instead of TrueHD because it has the capability to create a TrueHD stream on-the-fly.
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post #9 of 27 Old 09-20-2019, 10:10 AM
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When you select BitStream Dolby Digital or BistStream DTS, what actually happens is that Xbox will realtime re-encode PCM audio back into Dolby Digital or DTS of your choice. It doesn't mean it did carry the original audio over. This is necessary for old receivers that use optical connection but a complete waste of time for modern HDMI receivers because re-compress PCM audio into lossy DD or DTS cause audio quality loss.

Xbox does not have true bit stream audio. That's long been established and Microsoft doesn't see anything wrong with that.
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post #10 of 27 Old 09-20-2019, 12:42 PM - Thread Starter
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When you select BitStream Dolby Digital or BistStream DTS, what actually happens is that Xbox will realtime re-encode PCM audio back into Dolby Digital or DTS of your choice. It doesn't mean it did carry the original audio over. This is necessary for old receivers that use optical connection but a complete waste of time for modern HDMI receivers because re-compress PCM audio into lossy DD or DTS cause audio quality loss.
There isn't any audio quality loss when the Xbox is converting PCM audio to Dolby TrueHD or DTS HD-MA, which are lossless. However, if the Xbox decodes the audio stream from Netflix (or Hulu, etc). to PCM, discards any metadata that is in that stream, mixes audio from all currently running apps together, then encodes the final audio mix in the output format that the user has chosen in settings, then the loss of the metadata that was in Netflix's or Hulu's audio stream is a problem.
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post #11 of 27 Old 09-20-2019, 12:55 PM
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Xbox can't re-encode to trueHD or DTS HD. Only DD 5.1 or DTS 5.1

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post #12 of 27 Old 09-20-2019, 02:31 PM - Thread Starter
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Xbox can't re-encode to trueHD or DTS HD. Only DD 5.1 or DTS 5.1
I went into my Xbox's settings --> "Display & sound" --> "Audio output" and looked at my speaker audio bitstream format choices when the HDMI option I've selected is "bitstream out", and the bitstream format options are "DTS Digital Surround", "Dolby Digital", and "Dolby Atmos for home theater". Hmm, somehow it never occurred to me that here, "DTS Digital Surround" means DTS *core*, and "Dolby Digital" means plain-old AC-3. I don't know why I never noticed that DTS HD-MA and Dolby TrueHD aren't listed. I guess that you're right--maybe Xbox One can't live-convert to those two formats on-the-fly. It *can* live-convert to "Dolby Atmos for home theater", since that is listed as an output format. Maybe, then, the listing "Dolby Atmos for home theater" doesn't mean Atmos via Dolby TrueHD--because TrueHD isn't listed as an option. Very weird--maybe it actually IS Atmos via PCM (PCM + Atmos metadata).
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post #13 of 27 Old 09-20-2019, 02:44 PM - Thread Starter
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Here is confirmation that Netflix can stream Atmos on Xbox One. When Netflix is streaming an Atmos-encoded title on an Xbox One, is the Xbox decoding the Atmos but somehow maintaining the audio object metadata, and outputting everything as PCM plus Atmos audio objects?

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post #14 of 27 Old 09-20-2019, 04:23 PM
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TrueHD and DD+ are just compression methods to make the audio stream easier to transport over network. These audio streams need to be uncompressed first before can be processed for objects. So, the uncompressed format will be based on PCM audio and meta data. That's exactly what Xbox 1 sends out in bitstream Atmos mode. Besides, games often need to generate sound on the fly (game audio). So an Atmos game can't afford to, nor need to, spend time and resource to compress those audio into TrueHD or DD+ on the fly anyway. I'm not aware any realtime TrueHD encoding mechanism out there. They are typically compressed beforehand which obviously won't work for games.
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post #15 of 27 Old 09-20-2019, 07:50 PM - Thread Starter
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TrueHD and DD+ are just compression methods to make the audio stream easier to transport over network. These audio streams need to be uncompressed first before can be processed for objects. So, the uncompressed format will be based on PCM audio and meta data. That's exactly what Xbox 1 sends out in bitstream Atmos mode.
So, an uncompressed, Atmos-encoded soundtrack is simply a PCM soundtrack with Atmos metadata? I assume that all Atmos-encoded soundtracks have been compressed using Dolby technologies, and PCM soundtracks with Atmos metadata exist only as an interim stage after being decompressed from the source and before being processed for Atmos objects. I probably wouldn't be able to find a TV show or a movie with a PCM soundtrack that includes Atmos metadata on a Blu-ray or on a streaming service.

It sounds as if the Xbox One is unique in that (probably) few or no other source devices will feed a AVR a PCM stream with Atmos metadata.
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post #16 of 27 Old 09-20-2019, 08:07 PM - Thread Starter
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When you select BitStream Dolby Digital or BistStream DTS, what actually happens is that Xbox will realtime re-encode PCM audio back into Dolby Digital or DTS of your choice. It doesn't mean it did carry the original audio over. This is necessary for old receivers that use optical connection but a complete waste of time for modern HDMI receivers because re-compress PCM audio into lossy DD or DTS cause audio quality loss.
Some time ago, I was looking at AVRs at a store that sells used audio equipment, and they were old--most of them did not have HDMI, but at least one of them did, and if I recall correctly, it didn't have the Dolby TrueHD logo nor the DTS HD-MA logo on its front, only the original Dolby Digital logo and the original DTS logo. It must have been one of the first AVRs to have HDMI inputs, before Dolby TrueHD and DTS HD-MA were prevalent. If I had that AVR and wanted to use it with my Xbox One, I'd have to bitstream audio over HDMI in lossy Dolby Digital or in lossy DTS format, or instead send it PCM audio. That's probably why my Xbox One offers lossy Dolby Digital or DTS over HDMI. However, if I had one of those old AVRs, I suppose that 5.1 or 7.1 PCM would be a better option.
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post #17 of 27 Old 09-20-2019, 08:56 PM - Thread Starter
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I just connected my PC--a 2017 Surface Pro, running Windows 10--to my AVR, opened the Netflix app on both my PC AND on my Xbox, went to the exact same episode of the same show on both, went to the same moment in that episode on both, and started playback on the PC while switching my AVR's dynamic range control on and off. I could tell a difference between dynamic range control being on and being off. Then, I switched to my Xbox and started playback while switching dynamic range control on and off. I could not tell a difference between dynamic range control being on vs. being off. That suggests that when my Xbox decodes the Dolby Digital+ audio track from Netflix, it discards the dynamic range control metadata, as I was worried that it was doing, while my PC instead bitstreams the audio track to my AVR, which preserves the dynamic range control metadata.

Perhaps it is possible for app developers such as Netflix and VUDU to implement dynamic range control as an option in those apps' settings, like how dynamic range control is an option for Blu-rays and DVDs in Settings --> Disc & Blu-ray --> Blu-ray. That way, DRC would be applied when the Xbox processes the audio, before it hands the audio off to my AVR.

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post #18 of 27 Old 09-21-2019, 07:21 AM
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However, if I had one of those old AVRs, I suppose that 5.1 or 7.1 PCM would be a better option.
Unless you have games that are really Atmos (or PCM 7.1 which is extremely rare today) or you prefer use Xbox for streaming, PCM 5.1 is a best setting for now. That's what I use today even though I have a 7.2.2 system setup. I prefer my AVR to do DTS:X processing with PCM 5.1 than the fake Atmos from Xbox. One of the main reason I don't use Atmos or PCM 7.1 settings is because for the 5.1 game audio or non-Atmos streaming, the back surrounds are always silent because that's how Xbox send out audio when dealing with 5.1 source (send out 7.1 with two silent back surround channels).

That could change soon when Call Of Duty 2019 formally supports Atmos in game.
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post #19 of 27 Old 09-21-2019, 03:06 PM - Thread Starter
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I made a couple of screenshots in the main XBox One X Forum which will aid in proving Foxbat121's point. I noticed that while using the Plex Addon for Kodi, although I'm seeing "Direct Play" for both audio and video streams, my AVR will point out the audio stream is Dolby Atmos no matter the format.


If I were to use my Nvidia Shield or Oppo 203 to stream content with Lossless audio, my AVR will display Dolby True HD alongside Dolby Atmos. If the content is lossy, it will say Dolby Digital Plus along with Dolby Atmos, for example.

With the Xbox One, it's just Dolby Atmos alongside Dolby Atmos.
I found your first post in the official Xbox One X thread in which you bring up this subject, and I think I'll quote the most relevant posts in that thread (so far) on this subject because this subject applies not only to Xbox One X, but also to original Xbox One and to Xbox One S.

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the XB1X Dolby Atmos (MAT 2.0) is "Always on" (with the known exception of disc playback where "untouched bitstream" output is allowed), with all known current bugs and limitations.
I know what Dolby Atmos is, but what is MAT and, more specifically, what is MAT 2.0?

I think that untouched bitstream output might be called 'bitstream passthrough' or 'passthrough bitstream' because technically, Xbox Ones can create an original AC-3 or a DTS core bitstream on-the-fly for old receivers like the one that I used to use that don't have Dolby TrueHD nor DTS HD-MA, and that on-the-fly stream is also called a bitstream, so a more precise phrase--'passthrough bitstream'--that indicates that the audio stream is being passed through to the user's audio equipment without being decoded by the source device, has to be used.

What are the known bugs and limitations of always-on Dolby Atmos MAT 2.0 (whatever "MAT" is)? I probably already know what some of them are, but it would help other readers if there was a list.

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The screenshots that display Lossless audio are from the Plex Add-on for Kodi.

When using the native Plex App for the Xbox, the audio is Transcoded (aac).

However, in the grand scheme of things, my AVR tells the real story of what is going on with the audio. It's all Atmos (Dolby MAT).

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Here are screenshots of Playback using the Nvidia Shield.

Notice what my AVR reports back.

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Here are screenshots of Playback using the Xbox One X.

What the AVR is reporting back is the key.

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post #20 of 27 Old 09-22-2019, 03:39 PM - Thread Starter
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I just popped one of my Blu-rays--Ghost--into my Xbox, went to settings and disabled 'allow my receiver to decode audio', then played a dialog-only scene, then opened VUDU (where I own that same movie), and played that same scene, and the volume on VUDU was considerably louder. Since both apps' audio is being decoded by the Xbox, shouldn't the Xbox One operating system set the same reference level (if that is the correct term) for both apps?

I was about to ask if other streaming media devices set the same level for all apps, but then I remembered that other streaming devices bitstream those apps' audio without processing it, so it is up to the users' audio equipment to set the same reference volume level for all connected devices.

If I'm wrong, and Netflix (for example) is louder than VUDU (for example) on some streaming devices, please let me know.

I did another experiment with that same movie on VUDU, and set the volume level during the dialog-only scene on to what felt comfortable to my ears. That scene is followed immediately by an action scene, and I watched and listened to a part of both scenes. Then I went to the dialog scene on my Blu-ray copy in the Blu-ray Player app, set the volume level to what felt comfortable to my ears, and watched and listened to the same moments I had just watched and listened to on VUDU. On Blu-ray, the action scene seemed to be louder than on VUDU. Those two scenes together seemed to have wider dynamic audio range on Blu-ray than on VUDU. Why? I think I read somewhere that audio bit rate sets a maximum allowable dynamic range, so maybe that has something to do with it. It would be nice if, on Xbox One, there was a way to find out the streaming audio bitrate and video bitrate on VUDU, Amazon Video, etc. This is possible on Netflix by pressing down on the right thumbstick while a video is playing.

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post #21 of 27 Old 09-22-2019, 04:47 PM
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There is no reason to believe BD audio track is the same as streaming services, dynamic range wise. Audio tracks on BD should have more dynamic range and hence slightly softer or lower volume.

Also, Xbox doesn't have any audio leveling built-in. That's the job of final playback device, e.g. AVR.

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post #22 of 27 Old 10-13-2019, 10:26 PM - Thread Starter
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Quote:
Originally Posted by Foxbat121 View Post
Also, Xbox doesn't have any audio leveling built-in. That's the job of final playback device, e.g. AVR.
Can we be sure that when an Xbox One user is streaming a TV show on Netflix with 5.1 or more channels of sound, the Dolby metadata included in that Netflix stream isn't simply being discarded? Maybe the Xbox is using it to process the stream as it decodes it to PCM; if the decoded stream has already been processed according to the instructions in the metadata, then there's no need to pass that metadata along to the AVR.
My posts in this thread might suggest that the Xbox isn't acting on this metadata and is simply throwing it away.

TV: LG 47LW5700, AVR: Onkyo TX-NR787, speakers: DCM KX speakers:DCM KX-12 Series 2 (as front left and front right), DCM KX Center Series 2, DCM KX-6 Series 2 (as side surround left and right), sources: Xbox One S, Playstation 2 (fat model), Nintendo GameCube (model with digital AV output) with GameBoy Player, Panasonic VCR (PV-4661), PC: Microsoft Surface Pro (5th generation), phone: iPhone 7 Plus

Last edited by Drew Neilson; 10-13-2019 at 10:42 PM.
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post #23 of 27 Old 10-14-2019, 03:56 AM
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It is throwed away. There is no separate meta data in a Dolby track specifically for sound leveling. The sound leveling technique utilizes one of the compression parameter for that purposes: a segment of Dolby compressed audio will start with a DC component that represents average volume of that segment. The encoder then uses the difference between current audio level and the referenced average (or AC data) to perform the compression. So, a decoder will need to use this DC component to fully reconstruct the audio back to PCM. Since you have this DC component during the decoding time, it is easy to use that as a reference to perform auto-leveling of the output. Once audio is decoded into PCM, this information is gone. There is no way to carry it over to next device. So, unless you see an explicit configuration for audio leveling in Xbox, this typically show up as Dynamic range compression or night mode, you can be sure such functionality does not exist.
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post #24 of 27 Old 10-14-2019, 06:38 PM - Thread Starter
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Originally Posted by Drew Neilson View Post
I just connected my PC--a 2017 Surface Pro, running Windows 10--to my AVR, opened the Netflix app on both my PC AND on my Xbox, went to the exact same episode of the same show on both, went to the same moment in that episode on both, and started playback on the PC while switching my AVR's dynamic range control on and off. I could tell a difference between dynamic range control being on and being off. Then, I switched to my Xbox and started playback while switching dynamic range control on and off. I could not tell a difference between dynamic range control being on vs. being off. That suggests that when my Xbox decodes the Dolby Digital+ audio track from Netflix, it discards the dynamic range control metadata, as I was worried that it was doing, while my PC instead bitstreams the audio track to my AVR, which preserves the dynamic range control metadata.

Perhaps it is possible for app developers such as Netflix and VUDU to implement dynamic range control as an option in those apps' settings, like how dynamic range control is an option for Blu-rays and DVDs in Settings --> Disc & Blu-ray --> Blu-ray. That way, DRC would be applied when the Xbox processes the audio, before it hands the audio off to my AVR.
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Originally Posted by Foxbat121 View Post
Also, Xbox doesn't have any audio leveling built-in. That's the job of final playback device, e.g. AVR.
Quote:
Originally Posted by Foxbat121 View Post
It is throwed away. There is no separate meta data in a Dolby track specifically for sound leveling. The sound leveling technique utilizes one of the compression parameter for that purposes: a segment of Dolby compressed audio will start with a DC component that represents average volume of that segment. The encoder then uses the difference between current audio level and the referenced average (or AC data) to perform the compression. So, a decoder will need to use this DC component to fully reconstruct the audio back to PCM. Since you have this DC component during the decoding time, it is easy to use that as a reference to perform auto-leveling of the output. Once audio is decoded into PCM, this information is gone. There is no way to carry it over to next device. So, unless you see an explicit configuration for audio leveling in Xbox, this typically show up as Dynamic range compression or night mode, you can be sure such functionality does not exist.
I think that I saw a picture of a beta version of the Dolby Access app that had a 'night mode' or a 'dynamic range control' option. It might have been alongside the option to upmix audio to Atmos. I don't remember whether that picture was of the app running on a PC or on an Xbox, but it's probably only for Windows Insiders or Xbox Insiders at this time. (Unless this version of the Dolby Access app has gone public--see below).

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Unless you have games that are really Atmos (or PCM 7.1 which is extremely rare today) or you prefer use Xbox for streaming, PCM 5.1 is a best setting for now. That's what I use today even though I have a 7.2.2 system setup. I prefer my AVR to do DTS:X processing with PCM 5.1 than the fake Atmos from Xbox. One of the main reason I don't use Atmos or PCM 7.1 settings is because for the 5.1 game audio or non-Atmos streaming, the back surrounds are always silent because that's how Xbox send out audio when dealing with 5.1 source (send out 7.1 with two silent back surround channels).

That could change soon when Call Of Duty 2019 formally supports Atmos in game.
You're saying that games and apps that aren't 7.1 don't use the surround-back channels? But now I'm confused, because you referred to
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the fake Atmos from Xbox
which suggests that you've gotten the upmixing update. If your Xbox is upmixing non-Atmos sources to Atmos, then why isn't it sending audio to the surround-back channels?

TV: LG 47LW5700, AVR: Onkyo TX-NR787, speakers: DCM KX speakers:DCM KX-12 Series 2 (as front left and front right), DCM KX Center Series 2, DCM KX-6 Series 2 (as side surround left and right), sources: Xbox One S, Playstation 2 (fat model), Nintendo GameCube (model with digital AV output) with GameBoy Player, Panasonic VCR (PV-4661), PC: Microsoft Surface Pro (5th generation), phone: iPhone 7 Plus
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post #25 of 27 Old 10-15-2019, 06:16 AM
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You're saying that games and apps that aren't 7.1 don't use the surround-back channels? But now I'm confused, because you referred to
which suggests that you've gotten the upmixing update. If your Xbox is upmixing non-Atmos sources to Atmos, then why isn't it sending audio to the surround-back channels?
Xbox does not perform upmix from 5.1 to 7.1. So it is up to the apps or games to deal with it. Most of them just output 5.1 with 2 silent back surround channels as 7.1 LPCM if you choose such. And your receiver will not perform any upmix (other than Atmos or DTS:X height upmix).

The early version of Dobly Access app did upmix in Xbox but it was later disabled and now will be re-enabled in next release. However, that easily version of upmix only converts LPCM 7.1 to Atmos. So, if you have a 5.1 game, you will still have two silent back surround channels.

The only app that does proper 5.1 to 7.1 conversion is the Xbox media player app. In the early days, this app erroronusly output 5.1 audio to back surrounds with silent side surrounds. Later, MS fixed the issue and matrixed the surround channels to both back and side surrounds.

When I say fake Atmos, I mean currently when you choose Atmos bitstream, you always get audio stream labeled as Atmos even though we know it does not upmix any non-Atmos audio yet. This prevents your receiver to apply any Atmos or DTS:X upmix.
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I don't know if I've already mentioned this in this thread, but I only have a 5.0 speaker setup, which is why I don't already know how Xbox One handles 7.1 output. I wanted to know how Xbox One handles 7.1 output because I might have back surround speakers in the future.

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Xbox does not perform upmix from 5.1 to 7.1. So it is up to the apps or games to deal with it. Most of them just output 5.1 with 2 silent back surround channels as 7.1 LPCM if you choose [that audio output option in Xbox One system settings] [clarification added.]. And your receiver will not perform any upmix (other than Atmos or DTS:X height upmix [but it will not add sound to the back surround channels]) [Clarification added again.].
Wow. That stinks. Even with my 5.0 setup, I was already vaguely familiar with my Xbox not upmixing 2.0-channel content to 5.0.

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The early version of Dobly Access app did upmix in Xbox but it was later disabled and now will be re-enabled in next release. However, that easily version of upmix only converts LPCM 7.1 to Atmos. So, if you have a 5.1 game, you will still have two silent back surround channels.
How do you know that the upcoming version of Dolby Access won't upmix from 2.0 or 5.1 to 5.1 or 7.1, and will only add height?

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Originally Posted by Foxbat121 View Post
The only app that does proper 5.1 to 7.1 conversion is the Xbox media player app. In the early days, this app erroronusly output 5.1 audio to back surrounds with silent side surrounds. Later, MS fixed the issue and matrixed the surround channels to both back and side surrounds.
I had figured that upmixing was on a per-app basis, and that some apps do it, and others don't. When I first got my Xbox, I noticed, and was annoyed, that when I watched old 2.0-channel, Dolby-Surround-encoded content on Netflix, Netflix would send the left channel to my front-left speaker, and the right channel to my front-right speaker, and would leave my center and two surround speakers silent. And since the Xbox was outputting it in a 5.1 wrapper, there was no way for my AVR to apply upmixing to restore the content's original Dolby Surround mix. Now, it is easy for me to forget that Netflix doesn't upmix, since most of the content that I watch is in 5.1 (or more, for all I know, but obviously I don't hear more than 5.0). I DO know that Spotify upmixes music to 5.0 and I don't like it. So it does seem like it's up to individual app developers to implement their own upmixing, and I have no idea what algorithms they are using to upmix.

TV: LG 47LW5700, AVR: Onkyo TX-NR787, speakers: DCM KX speakers:DCM KX-12 Series 2 (as front left and front right), DCM KX Center Series 2, DCM KX-6 Series 2 (as side surround left and right), sources: Xbox One S, Playstation 2 (fat model), Nintendo GameCube (model with digital AV output) with GameBoy Player, Panasonic VCR (PV-4661), PC: Microsoft Surface Pro (5th generation), phone: iPhone 7 Plus
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I read an article a while back by a Dolby Engineer about how the Dolby Access app works. Don't have the link. Like Windows 10, Xbox is a unified audio system. If you set it up as 7.1, it will always assume 7.1 audio. If you set it up as 5.1, it will always assume 5.1. There is no way to label per app output. The HDMI handshake also determines if you have a 5.1 system vs 7.1 system. Since I have the 7.1.2 setup, I have to manually configure Xbox to output LPCM 5.1 for best experience for now because I don't want two silent rears.
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