No, they consist of 7 bed channels and a variable (2/4/6) number of height channels. The audio stream consists of a discrete bed layer, which is your standard 7.1 audio stream (for compatibility with non spatial audio systems) and a series of objects and locations. The audio renderer takes those objects, removes them from the bed stream (they were embedded so you get all the audio still if you lack a spatial audio setup) and given the speaker layout, calculates the phasing, volume and mixing effects to play that object in the desired location. The object may play from multiple speakers at different volumes and phases to create the effect.
-
Get an exclusive sneak peek into our new project. >>> Click Here
Questions about Dolby Atmos, as Well as the DTS Version (I Forget what It's Called)
Do these formats consist of ten discrete channels (Front Left, Center, Front Right, Surround Left, Surround Back Left, Surround Back Right, Surround Right, Height Left, Height Right, and Subwoofer)? Or do these formats consist of the standard eight channels (Front Left, Center, Front Right, Surround Left, Surround Back Left, Surround Back Right, Surround Right, and Subwoofer) with an encoder/decoder similar to Pro Logic, Neo6, etc.?
1 - 20 of 21 Posts
The stored format doesn't actually have an literal concept of "height channels". Anything not in the 7 bed channels is an object source, with an arbitrary location and size. So the soundtrack might have a temporary "bird" channel that moves across the stage, then the playback will render that out of whatever speakers you have, mapping 3D position to available speakers. There can be up to 20 objects at a time in the domestic Atmos version, IIRC.
However, the mixing engineer may choose not to use the full 3D object system, and could indeed just choose to place 4 permanent non-moving point objects in the position of height speakers, and mix it as if a fixed 7.1.4 channel setup. A fair few titles do this.
Many do a hybrid - they have 4 or fixed height objects and some dynamic objects. It's all the same to the player - it's all just objects, as far as it's concerned.
So it's very much discrete, not matrixed, but there's not a 1:1 channel-to-speaker mapping.
Things won't be localised to a single speaker only for reasons of positioning/spread, not due to failure to separate stuff from a matrix.
However, the mixing engineer may choose not to use the full 3D object system, and could indeed just choose to place 4 permanent non-moving point objects in the position of height speakers, and mix it as if a fixed 7.1.4 channel setup. A fair few titles do this.
Many do a hybrid - they have 4 or fixed height objects and some dynamic objects. It's all the same to the player - it's all just objects, as far as it's concerned.
So it's very much discrete, not matrixed, but there's not a 1:1 channel-to-speaker mapping.
Things won't be localised to a single speaker only for reasons of positioning/spread, not due to failure to separate stuff from a matrix.
So I should think of Atmos the same way I think of Dolby Pro Logic II, in which PL2 anolizes a discrete two channel stereo mix and adds stereo surround channels, except Atmos anolizes a discrete 7.1 channel mix and adds two to four height channels.
The stored format doesn't actually have an literal concept of "height channels". Anything not in the 7 bed channels is an object source, with an arbitrary location and size. So the soundtrack might have a temporary "bird" channel that moves across the stage, then the playback will render that out of whatever speakers you have, mapping 3D position to available speakers. There can be up to 20 objects at a time in the domestic Atmos version, IIRC.
However, the mixing engineer may choose not to use the full 3D object system, and could indeed just choose to place 4 permanent non-moving point objects in the position of height speakers, and mix it as if a fixed 7.1.4 channel setup. A fair few titles do this.
Many do a hybrid - they have 4 or fixed height objects and some dynamic objects. It's all the same to the player - it's all just objects, as far as it's concerned.
So it's very much discrete, not matrixed, but there's not a 1:1 channel-to-speaker mapping.
Things won't be localised to a single speaker only for reasons of positioning/spread, not due to failure to separate stuff from a matrix.
dolby's website is pretty good explaining it... i know you had a specific question but they do a good job explaining the tech
www.dolby.com
think of atmos less like 5.1 or 7.1 and more like 7.1 with meta data over the top. It's why your receiver doesn't just display atmos, it'll display atmos/dd+ or atmos/DTHD as it still has an underlying soundrack (ice cream) and atmos is the sprinkles on top.
Dolby Atmos - Official Site
Take your music and entertainment to the next level with Dolby Atmos, a revolutionary spatial audio technology for the most immersive sound experience.
www.dolby.com
think of atmos less like 5.1 or 7.1 and more like 7.1 with meta data over the top. It's why your receiver doesn't just display atmos, it'll display atmos/dd+ or atmos/DTHD as it still has an underlying soundrack (ice cream) and atmos is the sprinkles on top.
No. It's not like Dolby Pro Logic II where it has to extract/analyse the signals in the 2-channel audio mix to (re)create the surround. And where that analysis cannot recreate an arbitrary multichannel signal. The encode-decode process is lossy there.So I should think of Atmos the same way I think of Dolby Pro Logic II, in which PL2 anolizes a discrete two channel stereo mix and adds stereo surround channels, except Atmos anolizes a discrete 7.1 channel mix and adds two to four height channels.
In Atmos the 3D object information is in addition to the non-Atmos 7.1 mix; it's not encoded in the 7.1 audio, it's extra digital data. A non-Atmos receiver just ignores the Atmos data it doesn't understand and plays the 7.1 mix. An Atmos receiver processes the extra data.
There's no loss in it being carried alongside the 7.1 mix, and no "analysis" as such. There is signal subtraction going on to work backwards from the 7.1 mix to the Atmos mix, but it's all exact mathematical transformations. (Just like video data being stored as YCbCr (luma + chroma) despite being captured and displayed as RGB).
So Atmos is basicly a digital 7.1 stream with extra information a player and receiver can manage, process, and read if the player and receiver know how to read it. If they don't know how to read it, the Atmos data is ignored.
No. It's not like Dolby Pro Logic II where it has to extract/analyse the signals in the 2-channel audio mix to (re)create the surround. And where that analysis cannot recreate an arbitrary multichannel signal. The encode-decode process is lossy there.
In Atmos the 3D object information is in addition to the non-Atmos 7.1 mix; it's not encoded in the 7.1 audio, it's extra digital data. A non-Atmos receiver just ignores the Atmos data it doesn't understand and plays the 7.1 mix. An Atmos receiver processes the extra data.
There's no loss in it being carried alongside the 7.1 mix, and no "analysis" as such. There is signal subtraction going on to work backwards from the 7.1 mix to the Atmos mix, but it's all exact mathematical transformations. (Just like video data being stored as YCbCr (luma + chroma) despite being captured and displayed as RGB).
Yes. Although the player doesn't have to understand it anyway - it just needs to pass the entire bitstream to the receiver. So Atmos works with any Dolby TrueHD or DD+-capable player (barring bugs). Just need to make sure it's in bitstream output mode rather than LPCM (so Blu-Ray secondary audio off, for example).
A similar "extra data" setup was used for DTS-HD Master Audio, which is a lossy DTS core with extra data to reconstruct the lossless signal. Things not understanding DTS-HD Master Audio just process the core stream.
A similar "extra data" setup was used for DTS-HD Master Audio, which is a lossy DTS core with extra data to reconstruct the lossless signal. Things not understanding DTS-HD Master Audio just process the core stream.
The home version of the Atmos format is made up of 7.1 channels + audio objects (objects = sounds not mixed into channels but instead given x,y,z coordinates in 3D space). There are a variety of ways it can be packaged and delivered.So Atmos is basicly a digital 7.1 stream with extra information a player and receiver can manage, process, and read if the player and receiver know how to read it. If they don't know how to read it, the Atmos data is ignored.
On disc, the Atmos bitstream is made up of multiple substreams for backwards compatibility. Inside the Atmos mix is the entire soundtrack as a 7.1 mix. Inside the 7.1 mix is the entire soundtrack as a 5.1 mix. Inside the 5.1 mix is the entire soundtrack as a 2.0 mix.
If you have an old Blu-Ray player with 2-channel analogue out, the player can decode just the 2.0 substream and ignore the rest of the substreams (5.1, 7.1, Atmos). If you have an older 7.1 receiver, then it can decode the substreams for 7.1 and ignore that Atmos substream.
Atmos soundtracks are packaged and delivered differently for streaming.
I don't believe that's technically true. The 7.1 in TrueHD is MLP - same basic format as used on DVD-Audio, but with extra channels.Inside the 7.1 mix is the entire soundtrack as a 5.1 mix. Inside the 5.1 mix is the entire soundtrack as a 2.0 mix.
There is a separate 5.1 Dolby Digital (AAC) signal in TrueHD backwards compatibility, at least on Blu-ray, but it's packaged alongside the 7.1. It's not processed by a MLP decoder - it's not the "core" for the 7.1 decode, unlike the DTS in a DTS-HD MA bistream. It's a duplicate. You either decode the MLP or the AAC, not both.
And a 5.1 Dolby Digital stream doesn't contain a 2.0 substream - a Dolby Digital decoder downmixes the 5.1 to generate 2.0 if necessary. (Or 2/1.0, 3/0.0, or 3/1.0 or 2/2.0) All DD decoders have to be able do 5-channel decode. Only thing they can ignore is the LFE.
Both of those arise from the history of the formats. DD originated in cinemas and Dolby didn't do 2-channel cinema decoders - non-5.1 setups would have been handled by mixing the output from the 5.1 decoder, or indeed just by playing the analogue Dolby Surround soundtrack. And MLP for DVD-Audio didn't need any backwards compatibility, as backwards compatibility was provided by the separate DVD-Video layer.
AAC is lossy compression used commonly with Apple iTunes and internet radio, not as a companion to Dolby lossless codecs. Maybe you meant AC3.There is a separate 5.1 Dolby Digital (AAC) signal in TrueHD backwards compatibility, at least on Blu-ray, but it's packaged alongside the 7.1. It's not processed by a MLP decoder - it's not the "core" for the 7.1 decode, unlike the DTS in a DTS-HD MA bistream. It's a duplicate. You either decode the MLP or the AAC, not both.
We just re-hashed this in the home Atmos thread, confirming the substream structure (2.0/5.1/7.1/Atmos) of TrueHD. It had the same structure when it was Meridian Lossless Packing on DVD-Audio (i.e., the first substream was the entire album as a 2-channel mix, the second substream recovered the 5.1 mix).And MLP for DVD-Audio didn't need any backwards compatibility, as backwards compatibility was provided by the separate DVD-Video layer.
The reason it's he same format is that Dolby bought the format from Meridian ages ago. The reason MLP exists is because DVD audio had to deal with bandwidth limitations on the medium - the DVD disc could not be read fast enough for lossless audio to be stored so it had to be compressed and it barely fits on the disc. That is why DVD audio discs do not have a video layer - there is not enough bandwidth for it. I do believe you can do low framerate pictures. It was basically a format to replace CD.
DVD audio is an audio format requiring a compatible player, which is why it was not as popular a format. Far more popular was a DVD "audio" format that was a Normal DVD video disc as those could be played on any DVD player, more akin to the music video. Of course, you lose lossless audio.
Meridian is more known today for promoting their money maker MQA format where they make licensing fees at every stage - from mixing (you license the encoder on a per track basis), to production and distribution (every disc has a license fee, and every track streamed a little money goes to them), to playback (all the player software and hardware also have to pay). If everyone adopts MQA they'd basically be the gatekeepers to music.
That's why the dolby digital "core" (or backwards compatible) stream is completely separate. It's also likely why DTS is far more popular on Blu-Ray - to use Dolby is effectively a slower two pass encoder as you're really encoding it twice - once for MLP and again for Dolby Digital.
DVD audio is an audio format requiring a compatible player, which is why it was not as popular a format. Far more popular was a DVD "audio" format that was a Normal DVD video disc as those could be played on any DVD player, more akin to the music video. Of course, you lose lossless audio.
Meridian is more known today for promoting their money maker MQA format where they make licensing fees at every stage - from mixing (you license the encoder on a per track basis), to production and distribution (every disc has a license fee, and every track streamed a little money goes to them), to playback (all the player software and hardware also have to pay). If everyone adopts MQA they'd basically be the gatekeepers to music.
That's why the dolby digital "core" (or backwards compatible) stream is completely separate. It's also likely why DTS is far more popular on Blu-Ray - to use Dolby is effectively a slower two pass encoder as you're really encoding it twice - once for MLP and again for Dolby Digital.
The DVD video spec allowed for 2 channels of 96/24 uncompressed PCM audio, so you could have high resolution lossless audio without resorting to the DVD-A format. A handful of audiophile music labels took advantage of this.DVD audio is an audio format requiring a compatible player, which is why it was not as popular a format. Far more popular was a DVD "audio" format that was a Normal DVD video disc as those could be played on any DVD player, more akin to the music video. Of course, you lose lossless audio.
See:
Depends on the receiver:think of atmos less like 5.1 or 7.1 and more like 7.1 with meta data over the top. It's why your receiver doesn't just display atmos, it'll display atmos/dd+ or atmos/DTHD as it still has an underlying soundrack (ice cream) and atmos is the sprinkles on top.
Press the Status or Info button and the receiver will tell you if the signal is DD+ or TrueHD. AppleTV uses an extension of PCM called Dolby MAT which is simply reported as "Dolby Atmos".
The point is that Atmos is not its own audio codec. It is only an extension to existing ones.
See the first 2 points of this guide:
The Ultimate Dolby Atmos Guide | Nakamichi USA | True Surround Soundbar with Dolby Atmos & DTS:X
The Ultimate Dolby Atmos Guide. The essential information about Dolby Atmos, Dolby TrueHD, Dolby Digital Plus and Dolby MAT. Also, a complete list of streaming devices and apps that offer Dolby Atmos and Dolby Vision.
www.nakamichi-usa.com
I am aware. I am simply showing that what is displayed by the AVR differs by brand.Press the Status or Info button and the receiver will tell you if the signal is DD+ or TrueHD. AppleTV uses an extension of PCM called Dolby MAT which is simply reported as "Dolby Atmos".
The point is that Atmos is not its own audio codec. It is only an extension to existing ones.
See the first 2 points of this guide:
The Ultimate Dolby Atmos Guide | Nakamichi USA | True Surround Soundbar with Dolby Atmos & DTS:X
The Ultimate Dolby Atmos Guide. The essential information about Dolby Atmos, Dolby TrueHD, Dolby Digital Plus and Dolby MAT. Also, a complete list of streaming devices and apps that offer Dolby Atmos and Dolby Vision.
If you dig into the surround modes it will show "Dolby Atmos/DSur".
that's odd. so you have no idea if you're getting lossless dthd or compressed ddp? I would be annoyed at that. I like that my yamaha will even tell me if it's using a surround decoder by flashing the codec and then that it's in dsur or whatever the dts equivalent is. Not to mention it lights up all the speakers in use. This was helpful for me when I thought I was getting 5.1 from youtube tv and then put it in straight mode and realized it was f'n stereo.
Mine does the same for other formats. It's just Atmos that's a special child.that's odd. so you have no idea if you're getting lossless dthd or compressed ddp? I would be annoyed at that. I like that my yamaha will even tell me if it's using a surround decoder by flashing the codec and then that it's in dsur or whatever the dts equivalent is. Not to mention it lights up all the speakers in use. This was helpful for me when I thought I was getting 5.1 from youtube tv and then put it in straight mode and realized it was f'n stereo.
Also, I've noticed I can sometimes apply DSur or Neural X to DTS HD/Master. But sometimes, it doesn't let me. Those options disappear. Any idea why? I need to ask in my AVR thread.
So if you have an atmos track, there's nothing you can do with surround encoders as atmos is directing everything and doesn't need or want help. But, if you have a dd+ or DTHD, DTSMA etc track without atmos that is just 5.1/7.1 but you have presence enabled speakers (overhead), then it can still take this track and simulate the overhead noise of a chopper, bullets, ambiance whatever.Mine does the same for other formats. It's just Atmos that's a special child.
Also, I've noticed I can sometimes apply DSur or Neural X to DTS HD/Master. But sometimes, it doesn't let me. Those options disappear. Any idea why? I need to ask in my AVR thread.
For what it's worth I leave the decoders on as I think my yamaha does a good job of simulating that and it doesn't distract. Even neural-x on a videogame seems to work well. However, some purists may want to just go straight mode, no encoders and leave those 2 or 4 overhead presence speakers quiet if their source material doesn't actually have content for them. I guess the idea here is, no interference/manipulation and you're hearing it the way it was meant to be heard.
I think so, too. But I would like to know why on some material, the upmixing options for DTS-HD disappear.So if you have an atmos track, there's nothing you can do with surround encoders as atmos is directing everything and doesn't need or want help. But, if you have a dd+ or DTHD, DTSMA etc track without atmos that is just 5.1/7.1 but you have presence enabled speakers (overhead), then it can still take this track and simulate the overhead noise of a chopper, bullets, ambiance whatever.
For what it's worth I leave the decoders on as I think my yamaha does a good job of simulating that and it doesn't distract. Even neural-x on a videogame seems to work well. However, some purists may want to just go straight mode, no encoders and leave those 2 or 4 overhead presence speakers quiet if their source material doesn't actually have content for them. I guess the idea here is, no interference/manipulation and you're hearing it the way it was meant to be heard.
1 - 20 of 21 Posts
- This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
AVS Forum
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!
Full Forum Listing
Top Contributors this Month
View All
WilliamR
961 Replies
BASSAHOLIC
529 Replies
bass addict
401 Replies
Recommended Communities
