What's the difference between theatrical DTS/DD and DVD DTS/DD? (1 Viewer)

I'm hoping that some of you can clear up some questions I have and some gaps in my understanding of the various sound mixes:
MAIN QUESTION:
What's the difference between theatrical DTS/DD and DVD DTS/DD?
OTHERS:
Why are there no SDDS DVDs?
Is THX EX 7.1?
and why are there no DVDs in this format? Also, which movies have been released theatrically in the THX EX format (if there are too many, dont bother)?
Even though I'm unclear on a number of issues, I know that DTS/DD differences are misunderstood by some HTers, like OAR is misunderstood by J6P. But for me, I will be motivated to buy which ever version of a great movie, by which mix I heard in the theater, and if it was really good. Even if the same master is used to produce both DVD tracks, I just want to recreate my theaterical experience as accurately as possible - that includes the psychological comfort of knowing I'm listening to the same mix?
Nevertheless, I'd love to know if there are any fundamental differences between theatrical and domestic sound presentations, there by clearing up any questions in my mind, about accurately recreating the cinema experience at home!
Thanks.
Paul.

I believe the main difference between theatrical mixes and those for DVD is that of acoustic space; that is, the vastly different room sizes dictate different mixes.
As far as SDDS, Sony has stated it has no plans to release it as a home format.

Let me refine the first question...
Does theatrical DTS/DD have 5.1 channels of sound?
[Edited last by Paul Dalmaine on August 27, 2001 at 08:56 AM]

quote: Does theatrical DTS/DD have 5.1 channels of sound?[/quote] Yes, but just like the home version, the theatrical version can contain fewer than 5.1 channels. For example, I believe that Curse of the Jade Scorpion is currently playing in DD, but it's a mono film.
The theatrical version of DD 5.1 uses the same codec but a lower data rate than the home version (320kbps in the theatre vs. 384 or 448kbps at home). I believe the home version of DTS uses a different codec than the one used in theaters, but I'll have to defer to others more knowledgeable about DTS.
As already mentioned, 5.1 mixes are often redone for home versions, because the theatrical mixes are designed to be heard in spaces much larger than the typical home theater. There's a demonstration of such "near field" adjustment on the Se7en platinum edition DVD.
quote: Is THX EX 7.1? [/quote] No, it's 5.1, with an extra channel matrixed into the two rear channels. For home viewing, THX recommends playing that extra matrixed channel through two separate speakers arrayed behind the listening position; this is intended to best approximate the theatrical venue, where the matrixed rear center will be played through more than one speaker.
quote: and why are there no DVDs in this format? [/quote] There are, but it's almost never listed on the DVD case. If the movie was released in Surround EX, usually the DVD is too.
quote: Also, which movies have been released theatrically in the THX EX format (if there are too many, dont bother)?[/quote] Dolby maintains lists on its site of released and upcoming Surround EX films. There's also a regularly updated thread on this forum.
quote: Nevertheless, I'd love to know if there are any fundamental differences between theatrical and domestic sound presentations, there by clearing up any questions in my mind, about accurately recreating the cinema experience at home![/quote] The biggest single difference is the acoustic space itself. Unless you live in a mansion the size of Sydney Pollack's place in Eyes Wide Shut, it's unlikely that any home theater will ever have acoustic properties similar to the large space of a commercial theater. That doesn't mean the home theater won't sound good; in fact, it will probably sound better. But it does mean that "accuracy" in recreating the theatrical sound remains a relative concept.
M.
[Edited last by Michael Reuben on August 27, 2001 at 09:18 AM]

I'll have a go, though there are others better qualified here...
(if I've got some of the numbers wrong feel free to correct)
What's the difference between theatrical DTS/DD and DVD DTS/DD?
Aside from storage (DTS is on CD-ROM for theatrical, Dolby has on-film strip), there are also in bitrates. Dolby D theatrical runs at 320kbps while DTS is around the same rate as 'full rate' DVD DTS. Theatrical DTS is also incompatible with home DTS. Not sure if that applies to Dolby Digital. Both are 5.1 theatrical formats.
Why are there no SDDS DVDs?
Because Sony have always said that SDDS is theatrical only. SDDS uses ATRAC compression, similar (if not the same as) to that used on MiniDisc. It can run in 5.1 or 7.1 flavours (the latter using two extra front channels, inbetween centre and main left/right).
Is THX EX 7.1?
No. THX EX is 5.1 with a matrixed rear centre channel. Same as DTS ES. However DTS ES 6.1 Discrete is a true 6.1 format, with the rear centre being discrete. However this is a home format only and any films that are given DTS ES 6.1 soundtracks have to be specifically remixed (which is why there are very few of them).
which movies have been released theatrically in the THX EX format
Too many to mention. Check out Dolby.com or THX.com
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Damn, how does that Reuben fella do that ???

I studied your technique, Rob!
M.

So THX EX is just Dolby Digital EX, THX certified?

quote: So THX EX is just Dolby Digital EX, THX certified?[/quote] EX was a joint creation of THX and Dolby. I find the naming conventions utterly confusing, but I believe that "DD Surround EX" is the formal name for the theatrical version, "THX Surround EX" is the formal name for the home version, and they're effectively identical.
And even if I'm right about those naming conventions, no one follows them!
M.
[Edited last by Michael Reuben on August 27, 2001 at 09:56 AM]

I know it's nitpicking, but even DTS ES "DISCRETE" isn't really truly discrete per se. Yes, the center rear bitstream is discrete, but when it is being utilized, the center rear data is comparitively subtracted from the left and right surrounds. This is to maintain backwards compatibility with 5.1 systems.
In other words, in 5.1 you're still hearing all the sound, with anything intended to be directly behind you simply equal in both the left and right surround channels. But when you're in 6.1, it uses the discrete rear channel information to figure out what to remove from the left and right surrounds so that all three aren't playing those same sounds.
See... nitpicking... So sue me!

quote: I just want to recreate my theaterical experience as accurately as possible - that includes the psychological comfort of knowing I'm listening to the same mix?[/quote]
That is a noble goal, but as mentioned, changes have to be made for it to sound better in the smaller space of a home environment. Also, different soundtracks are sometimes encoded at different times in different studios as we have seen with some titles, so there are bound to be minor differeces here and there.
quote: ...but even DTS ES "DISCRETE" isn't really truly discrete per se[/quote]
I think this misconception perpetuates from a review of one of the Denon receivers by Brent Butterworth. Originally, he said it wasn't discrete, but later corrected himself although in the correction his wording was a bit muddy.
It truly is discrete when decoded by a ES discrete decoder. In the end, after the matrixed rear center information is subtracted from the LS & RS channels, what is left is 6.1 channels, each with it's own discrete information as designed by the engineers.
The discrete rear center information, delivered via extension data with the 5.1 channel information, is completely unaffected by the subtractive process in the LS & RS channels.
Don't worry, Jeremy, I won't sue you.
DJ
[Edited last by David Judah on August 27, 2001 at 12:03 PM]

Interesting, especially because some home versions of blockbuster movie soundtracks are ultra painful to my ears, unless I apply that THX (or THX-like) re-equalization to the mix. One wonders how much much remixing they're actually doing when making the home version of the soundtrack.
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Off topic:
Jeremy is right, DTS ES Discrete is NOT really 'discrete', not even when decoded through a ES Discrete decoder.
On topic:
- SDDS 7.1 at home doesn't make sense, since the 2 extra channels are only effective on very large screens (think 50-100 feet wide here)
- SDDS 5.1 at home would make sense in the same way DTS 5.1 at home makes kinda sense: having the choice between different codecs. DD vs DTS is unnerving enough, though.
- THX EX is not a sound standard per se. The movies are mixed and shown theatrical in Dolby Digital EX!
- THX EX is a 'decoding scheme' developed by Dolby and THX to optimally decode DD EX soundtracks at home. Similiar to THX4.0 for Prologic and THX5.1 for 5.1 sources. The scheme includes, as already mentioned, 2 center surround speakers (independent output level and time alignment) to reproduce the 'BACK' channel from the DD EX mix at home.
- most differences of DTS/DD DVD vs theater have been mentioned. Also:
DTS runs at 44.1 khz in theaters and on LD, but with 48khz on DVD (both on half and full rate DVDs)
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Thanks for clarifying that point Jeremy. Just goes to show how much interest I have in the EX/ES gimmick

It is not open to interpretation, Jeremy, as the process is very straightfoward. The plain, simple fact is that all of the discrete information that was mixed for each channel is reproduced when the process is finished.
I don't see how you can call that anything but discrete.
DJ

No, David. Its not that 'plain and simple'.

Theatrical DTS uses the APT-X ADPCM compression system. It's a 16-bit five-channel system with a sampling rate of 44.1kHz and a bit-rate of 882kbps. The LFE material isn't recorded as a discrete channel as it is in the domestic system, rather placed in the surround channels and extracted at the playback stage.
Domestic DTS uses DTS's proprietary Coherent Acoustics perceptual coding compression scheme. Current operating rates are 754kbps and 1509kbps on DVD at a sampling rate of 48kHz, and 1235kbps/44.1kHz on LaserDisc and CD. Sampling rates of 192kHz and 24-bit resolution are theoretically possible using this system, albeit not on DVD-Video.
Dolby Digital uses the conventional 5.1-channel configuration in theatres and operates at 320kbps/48kHz. Domestically, Dolby Digital operates at 32kbps-640kbps, although DVD's maximum bit-rate is restricted to 448kbps. Like DTS's domestic system, it nominally operates at 20-bit resolution and a sampling rate of 48kHz on DVD but (like DTS's domestic system) is also compatible with 24-bit source material.
Sony have the option to include SDDS on DVD-Video at their discretion, but have stated they have no plans to do so.
THX EX is not a 7.1 system; it isn't even a recording format, rather a playback/hardware application like Dolby Pro Logic. It extracts the matrixed centre-surround channel from Dolby Digital Surround EX-encoded 5.1 soundtracks. As a hardware application, there are no DVDs/software available in THX-EX, just as there are no DVDs available in Pro Logic (rather Dolby Digital Surround EX and Dolby Surround, respectively).
Adam
[Edited last by Adam Barratt on August 27, 2001 at 06:28 PM]

I knew I should have waited for Adam.

quote: The LFE material isn't recorded as a discrete channel as it is in the domestic system, rather placed in the surround channels and extracted at the playback stage.
[/quote]
This is the only criticism I have with theatrical DTS which is why in theatres, the DTS surround extension goes only down to 80 Hz.
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[Edited last by John Stockton on August 27, 2001 at 06:42 PM]