Atmos and TrueHD 7.1 playback on 5.1 systems - Tests, Results, questions, experiences

[kfbkfb]

The MAGNAVOX manual doesn't say where it gets the DD track to output when a TrueHD track is selected/playing (before investigating this issue, I thought the player decoded the TrueHD track and then encoded it into DD).


Kirk Bayne

 

[mutant_matt]

The MAGNAVOX manual doesn't say where it gets the DD track to output when a TrueHD track is selected/playing (before investigating this issue, I thought the player decoded the TrueHD track and then encoded it into DD).


Kirk Bayne

Seems unlikely. Presumably, it'll "find" the mandatory DD stream and just output that (digitally) via the coax output (and RCA analogue outs if it has them), regardless of what it might be outputting over HDMI...

 

[kfbkfb]

Presumably, it'll "find" the mandatory DD stream and just output that (digitally) via the coax output (and RCA analogue outs if it has them)

Right, I didn't think through how complicated it would be to do in player TrueHD -> DD, a separate required w/TrueHD DD track is the obvious cost effective answer to providing a semblance of the TrueHD surround sound for older A/V receivers (like mine).


And now...back to the regularly scheduled Pink Floyd DSotM thread...


Kirk Bayne

 

[Owen Smith]

Intellectual property??

You sue people when they use your intellectual property without a licence. And within the industry, keeping the documents secret won't help because a) they leak b) engineers move between companies c) engineers are smart and given time to experiment at work can figure things out.

 

[Owen Smith]

In-case people were not aware, Dolby TrueHD is nearing 20 years of age. And Dolby Atmos is over 10 years old!

There's been plenty of time to understand how they function. Even deconstruct them...

But the tools to do so are wrapped up in being a Dolby licencee, which costs more than any home enthusiast is willing to pay.

 

[Stupy]

Anyone know the default channel mapping for Dolby TrueHD 7.1 (may contain Atmos) -> DD 5.1 (I'll be listening to the DD 5.1 track on this Pink Floyd Atmos mix)?


Kirk Bayne

G'day Kirk,

May I recommend this thread... Atmos and TrueHD 7.1 playback on 5.1 systems - Tests, Results, questions, experiences

Cheers

 

[SeeMoreDigital]

But the tools to do so are wrapped up in being a Dolby licencee, which costs more than any home enthusiast is willing to pay.

No they're not... You can use 'third-party' applications such as: -

TSmuxer GUI (new open-source builds) to create fully compliant Blu-ray discs muxes (without menus). It can also be used to de-mux/create elementary video, audio and subtitle streams. This application was first created back in Jan 2008!

Eac3to to de-mux and mux elementary streams. It can also be used to add an AC3 core to Dolby TrueHD audio streams.

FFmpeg to create Dolby TrueHD audio streams (without an AC3 core).

With respect: Due to certain peoples lack of knowledge about how Dolby TrueHD needs muxed compliantly into the .m2ts container, this subject has gone on far longer than it should have done...

As I said before, I started creating fully compliant Blu-ray disc muxes years ago. If others here have never created fully compliant Blu-ray disc muxes with Dolby TrueHD audio, they should not be arguing with those of us who have!

 

[Owen Smith]

No they're not... You can use 'third-party' applications such as: -

The trouble with using third party applications is you don't know if you're creating something to Dolby's rules and intentions, or you're creating something that is technically invalid but happens to work on most players (possibly until some firmware update for them breaks it).

How do you know your Blu Ray discs are fully compliant? Is there some Dolby tool you can run that checks everything? Because the fact they play does not prove they are fully compliant.

 

[himey]

Someone should change the title of this thread and start a new one about the new Atmos mix of Dark Side of the Moon.

 

[harync]

Someone should change the title of this thread and start a new one about the new Atmos mix of Dark Side of the Moon.

I think that the all the DD/TrueHD discussion should go to the Thread that Stupy posted above: Atmos and TrueHD 7.1 playback on 5.1 systems - Tests, Results, questions, experiences

 

[SeeMoreDigital]

I think that the all the DD/TrueHD discussion should go to the Thread that Stupy posted above: Atmos and TrueHD 7.1 playback on 5.1 systems - Tests, Results, questions, experiences

Oh yes please. Anywhere but within this Pink Floyd topic. So I can ignore it

 

[harync]

The trouble with using third party applications is you don't know if you're creating something to Dolby's rules and intentions, or you're creating something that is technically invalid but happens to work on most players (possibly until some firmware update for them breaks it).

How do you know your Blu Ray discs are fully compliant? Is there some Dolby tool you can run that checks everything? Because the fact they play does not prove they are fully compliant.

I have done this with dozens of commercial Blu-rays, so I can assure you that compliant blu-rays structure the audio tracks this way. Here is the DSOTM Blu-ray main .m2ts file in TSmuxer:

You can see that the AC3 "core" and the TrueHD track are packaged as one stream. Using ffmpeg, you can split them into two separate files:

On my hardware, which is all capable of reading TrueHD, I can't choose to play the AC3 track. If one were to use an optical out from a blu-ray player to an AVR, I assume they would get the AC3 track. I assume a blu-ray player is doing this all behind the scenes. In order for me to hear the AC3 track, I have to demux it from the TrueHD and play it back as a separate file.

 

[kfbkfb]

So...those of us who are kinda living in the recent past will be getting DSotM in 448Kbps DD 5.1 (the single Blu-ray is this mastering [documented above], not a new mastering with a possibly higher DD data rate)?


Kirk Bayne

 

[Owen Smith]

So...those of us who are kinda living in the recent past will be getting DSotM in 448Kbps DD 5.1 (the single Blu-ray is this mastering [documented above], not a new mastering with a possibly higher DD data rate)?

It's already clear this is a different Blu Ray since it is two discs combined into one. Who knows what else they'll change in the process. But I'd be assuming the embedded DD is likely to be 448Kbps.

 

[kfbkfb]

I wish Dolby Labs would make the default "core" DD at 640Kbps and make the (UHD)Blu-ray authoring people manually select a lower data rate.


Kirk Bayne

 

[HomerJAU]

So Kirk, you can’t play TrueHD? If not you could probably pickup an old AVR with TrueHD/DTS-HDMA (pre Atmos) pretty cheaply.

If you do have TrueHD then play the Atmos stream and you’ll hear lossless audio.

 

[paligap]

I've lost the thread of this . . . thread (Not that I ever had it in my grasp). I recently moved the receiver and some player components from my Atmos setup to a temporary 5.1 setup. My question is this: Until I install and connect my overhead speakers, should I limit my players to output 5.1 or let them just keep sending Atmos to my receiver?

 

[harync]

I've lost the thread of this . . . thread (Not that I ever had it in my grasp). I recently moved the receiver and some player components from my Atmos setup to a temporary 5.1 setup. My question is this: Until I install and connect my overhead speakers, should I limit my players to output 5.1 or let them just keep sending Atmos to my receiver?

If you used room calibration that comes with your receiver (e.g. audyssey, ypao, mcacc) and you don’t remove the height speakers from the set-up in the receiver, I wonder if you would be missing any sound that Atmos or any DSP modes would be sending.

 

[minimumtumbleweed]

If you used room calibration that comes with your receiver (e.g. audyssey, ypao, mcacc) and you don’t remove the height speakers from the set-up in the receiver, I wonder if you would be missing any sound that Atmos or any DSP modes would be sending.

This depends on the AVR, but my Denon would not allow any Atmos processing at all without the height speakers physically connected to the device. So I imagine it would automatically be playing the 5.1 without them.

 

[kfbkfb]

So Kirk, you can’t play TrueHD? If not you could probably pickup an old AVR with TrueHD/DTS-HDMA (pre Atmos) pretty cheaply.

If you do have TrueHD then play the Atmos stream and you’ll hear lossless audio.

Can't play TrueHD yet, my basement home theater system will likely stay with just DS, DD and DTS (my Sony Blu-ray player will play the MCH SACD layer and encode it into Dolby Surround, which sounds fairly good decoded with Pro-Logic).


Kirk Bayne