Do this backwards: Where do 5.1 and Atmos parts appear in stereo

[jimfisheye]

This is not correct. Nothing is omitted. It just becomes 7.1. The height channels are already embedded in the bed channels. Atmos processing just re locates them from the beds to the heights.

It is correct and by design. Only the Atmos decoder can do that. If you rip/decode with anything other than running the ripped .mlp file through the dolby reference player in real time, you only get the 7.1 bed audio sans all object channels.
Really truly!

(Try it yourself for an experiment and see!)

Object rendering is done on playback with the Atmos decoder.
Any audio baked into the 7.1 bed is just that - part of the 7.1 bed. The decoder would not see object audio baked into the bed audio because there is no such thing with the format! Bed audio and objects are delivered separately. The decoder references your selected speaker array and renders the objects into the audio channels available on the fly on playback.

 

[sjcorne]

I agree with @LuvMyQuad, that’s definitely not how it works.

Say you’re working with an Atmos mix that has a guitar part exclusively in the front left height speaker. If you convert from TrueHD direct to 7.1 FLAC, said guitar will appear in the front left speaker on the resultant 7.1 file. It won’t just wipe the guitar out of the mix completely.

 

[zeerround]

Out of interest... Where can you find 9.1.6 encoded content on a disc. And what's the audio format?

Is it some Auro 3D encoded stuff?

Well literally the 9.1.6 notation is an Atmos thing. The highest setup I've seen listed for DTS:X is 9.2.2 (Smyth Realiser) and AVRs would probably call that 11.2.

I know I've seen 9.1.6 Atmos in streaming. Not sure about disk. Maybe Steven Wilson (but I think his home rig is 7.1.4?)?

I have my Smyth Realiser set to a 9.1.6 Room, and I can then mix to 9.1.6, 7.1.4, 7.1, 5.1, etc. without changing settings. Sometimes yeah I need to do something to get 5.1 rears to go to the rears (vs. sides) as discussed earlier, but I do that on the PC.

I've seen 22.2 Mpeg-h/Sony 360 RA streaming as well, but that's a whole 'nother story...

 

[sjcorne]

Most album covers just state "Atmos" and omit the channel array.

Isn’t that the point of having a channel-agnostic format?

 

[SeeMoreDigital]

It won’t just wipe the guitar out of the mix completely.

Actually it would, as only an atmos decoder is able to decode and re-map any of the Atmos elements/channels into the 'bed' channels.

And given that a playback device is unable to decode Atmos meta-data, it also can't be configured to re-map any of the Atmos elements/channels into the 'bed' channels.

 

[LuvMyQuad]

You guys can believe what you will but prior to having an Atmos system, I played many an Atmos recording back on a 5.1 system with no loss of information at all. I still can, by playing atmos m4a files on that same 5.1 system. All the information is still there, it just isn't re-distributed.

 

[himey]

You guys can believe what you will but prior to having an Atmos system, I played many an Atmos recording back on a 5.1 system with no loss of information at all. I still can, by playing atmos m4a files on that same 5.1 system. All the information is still there, it just isn't re-distributed.

I used an Apple TV 4K and an Oppo for a while, outputting 5.1, and it sounded great. There is a guy on AVS Forum who explains the process much better than I can, so I will leave it to him. His handle is "sdurani".

 

[jimfisheye]

Isn’t that the point of having a channel-agnostic format?

No! The point is having the mix translate to other speaker arrays. Both smaller and larger. Not to just gaslight the listener! A main point of Atmos is still to deliver a mix 1:1 when the consumer has the same speaker array it was mixed on.

Of course the idea is to also make channel-agnostic possible. It's a fine idea too and leads to a lot of positive stuff! I'm annoyed by what appears to be people abandoning the concept of audiophile listening and listening to a mix 1:1 on the same speaker array it was created on. This is the main point to me while the upmixing and downmixing are a secondary thing.

Original mix speaker array needs to be on the album cover!

So... I know I'm left field of "mainstream". Surround sound for me is purely for music and meaningless for movie soundtracks. I kind of thought I was in my kind of territory around here with that!

 

[SeeMoreDigital]

I used an Apple TV 4K and an Oppo for a while, outputting 5.1, and it sounded great. There is a guy on AVS Forum who explains the process much better than I can, so I will leave it to him. His handle is "sdurani".

Just in-case people are not aware... The Apple TV 4K does not pass bit-streamed audio via HDMI, it transcodes all audio formats to Dolby MAT (which is LPCM based). No doubt the Apple streaming service is performing some jiggery pokery to the "Atmos" audio too!

Either-way. My comments refer to disc based media, not streamed...

 

[LuvMyQuad]

Either-way. My comments refer to disc based media, not streamed...

So do mine.

 

[SeeMoreDigital]

Personally I would prefer that disc based 'Atmos' releases also include a dedicated 5.1 or 7.1 mix encoded in either lossless Dolby TrueHD or DTS-HD MA. Or even good old fashioned LPCM.

 

[jimfisheye]

Personally I would prefer that disc based 'Atmos' releases also include a dedicated 5.1 or 7.1 mix encoded in either lossless Dolby TrueHD or DTS-HD MA. Or even good old fashioned LPCM.

That does seem to be the MO right now. The 'official' formats are considered to be 2.0, 5.1, & 7.1.4 at present. I believe one is expected to turn in all 3.

 

[himey]

So do mine.

Mine too.

 

[sjcorne]

The labels rarely ask for 5.1 anymore, and - when you see one included on a Blu-Ray alongside Atmos nowadays - more often than not it's a re-render of the ADM file. The only mixers I know of that still turn in dedicated 5.1's (as in not derived from Atmos) are Steven Wilson and Bruce Soord.

 

[himey]

Just in-case people are not aware... The Apple TV 4K does not pass bit-streamed audio via HDMI, it transcodes all audio formats to Dolby MAT (which is LPCM based). No doubt the Apple streaming service is performing some jiggery pokery to the "Atmos" audio too!

Either-way. My comments refer to disc based media, not streamed...

Dolby TrueHD Atmos compatibility with any number of speakers is a marketing lie? That is just silly.

 

[sjcorne]

Actually it would, as only an atmos decoder is able to decode and re-map any of the Atmos elements/channels into the 'bed' channels.

And given that a playback device is unable to decode Atmos meta-data, it also can't be configured to re-map any of the Atmos elements/channels into the 'bed' channels.

When an Atmos mix is converted from ADM to TrueHD, all the beds and objects are combined into a 7.1 stream. However, the object-oriented information remains encoded with positional metadata readable only by the Dolby Renderer. If the Renderer is not in the signal chain (say one is using an old AVR or the analog 7.1 outs on their Blu-Ray player), this metadata is ignored but the audio information remains present in the mix at the intended level.

It's very easy to confirm this by listening back to any Atmos Blu-Ray with important musical elements in the top speakers. Some examples:

• The Who "Baby O'Riley" - the short guitar breaks at around 3:00 and 3:30 are mixed entirely to the height speakers.
• Gentle Giant "Design" - the a capella vocals starting at 3:27 are 100% in the four height speakers, with complete silence in the other channels.
• King Crimson "I Talk To The Wind" - if you were to mute the top array on this one, all the flutes would completely disappear.

 

[MidiMagic]

I still do not have my answer.

What happens if there is NO decoder in the music chain.

A DVD or BR player playing through a stereo set.

A DVD or BR player playing through a 2.1 soundbar.

Where do the sound images appear to be in each case? I want specific locations.

 

[jimfisheye]

I still do not have my answer.

What happens if there is NO decoder in the music chain.

...

No decoder?
Static sound! And quite loud!

But you probably meant with an older decoder that is not Atmos compatible.
The older decoders will only see the TrueHD 7.1 part of the file. All objects (including the height channels which must be treated as objects) are part of the metadata. The old pre-Atmos decoder can't read it and ignores it. Thus you only get the 7.1 bed audio. The height channels and any mix objects that would place in other channels are omitted.

It would be the modern version of listening to a stereo tape in someone's car where they only had one channel hooked up. Remember hearing that back in the day with a Beatles song (or other hard stereo mix like that)?

Atmos is copy protection first and foremost that aims to make you buy the decoder to hear the music.

 

[jimfisheye]

Dolby TrueHD Atmos compatibility with any number of speakers is a marketing lie? That is just silly.

Well, not quite. The copy protection element of it - ie. requiring a hardware based decoder unless you manage to get access to Dolby's reference player is just extra militant with Apple. The post-Jobs Apple with their blacklists, software spoofing and gaslighting... Channels 9-12 get muted for any media player except the Dolby player. Yes, even for straight 12 ch wav files! (There's a slick workaround for this, FYI. ) The Apple Music app's Atmos controls get blanked out if you don't have a subscription to Apple Music. (Haven't sluthed for a workaround for this yet...) They're going hard with this right now!

 

[sjcorne]

Again: The TrueHD 7.1 contains all of the audio information. If the Dolby Atmos Renderer is not in the user's signal chain, all of the object-oriented elements remain present at the mixer's intended level. But don't take my word for it, try converting an Atmos Blu-Ray directly to 7.1 FLAC (using something like AudioMuxer or DVD Audio Extractor) and see if any height info is missing - I cited some easy examples in the Stones thread.