Film-Tech Forum ARCHIVE: EPISODE II: what sound format did you use ? PCM 6ch, Dolby EX, DTS ES ?

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Topic: EPISODE II: what sound format did you use ? PCM 6ch, Dolby EX, DTS ES ?

David Baum
Film Handler

Posts: 90
From: Brussels, Belgium
Registered: Aug 2000

posted 05-20-2002 12:01 PM

TI seems to say all digital projections use uncompressed 24bits PCM on six channels ( uncompressed PCM is sort of a pleonasm

I suppose not every theater had access to this super high res sound format and dolby and dts was often used instead.

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Antonio Marcheselli
Phenomenal Film Handler

Posts: 1260
From: Florence, Italy
Registered: Mar 2000

posted 05-20-2002 12:59 PM

In Italy Fox didn't print SDDS track this time.

I'm using DTS at the moment.

Bye
Antonio

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Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 05-20-2002 01:02 PM

I feel pretty darn good about being able to present EPISODE II in DTS (2 locations) and Dolby Digital EX (1 location).

But, then, I'm also running 35mm film.

------------------

~Manny.

Now...where was I ?
Leonard Shelby, MEMENTO.

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David Baum
Film Handler

Posts: 90
From: Brussels, Belgium
Registered: Aug 2000

posted 05-20-2002 01:05 PM

hi Antonio

it "seems" the compulsory or prefered at least sound format accompanying the digital film is PCM. and backup or "second choice" being dolby, sdds, dts.

can anyone clarify this ? is there a synchronisation issue or is the prefered PCM track recommended by TI "one" of the reasons why there's so few 3DLP (aside from the cost but a quality argentic projector ain't no bargain either... ). Are dolby, dts for instance a bit "unhappy" because PCM encoding format has been the reommended choice by TI ? .....

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David Baum
Film Handler

Posts: 90
From: Brussels, Belgium
Registered: Aug 2000

posted 05-20-2002 01:48 PM

argh! I'm sorry, I meant "which sound format did you use with the 3DLP digital projection" ?

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 05-20-2002 07:20 PM

I didn't know that there were different sound formats for DLP. The Qubit that I've seen has discrete 6-channel outputs. I don't know about the Boeing or Technicolor systems.

It would probably be trivial to make this work with a standard DTS player (as long as the timecode matches up), but I can't see it being worth the bother. If anything, Dolby or Sony or DTS would probably just license their compression technology and the actual playback would be done off the hard disk.

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David Stambaugh
Film God

Posts: 4021
From: Eugene, Oregon
Registered: Jan 2002

posted 05-20-2002 07:30 PM

Get rid of as much of the outboard hardware as possible!! It's just more stuff to get screwed up.

Theaters are begging for a "black box" system with a green "START" button. That's all they seem to be able to handle, and it fits in perfectly with their policy of having the absolute minimum investment in training their personnel.

"Can you tell time? Can you press this green button? Congratulations, you are booth-certified!"

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001

posted 05-20-2002 07:56 PM

I thought the audio format for digital projection shows was 20-bit 48kHz 5.1 EX. 24-bit would be a bit surprising, although more and more music and movie audio masters are being archived at that bit depth. Too bad nearly all but the most profanely expensive of high end electronics products can get close to displaying true 24-bit dynamic range. I would say 20-bit is enough.

Also, I was under the impression the 5.1 PCM audio stream is part of the overall digital projection data stream, much in the manner that a DVD Video .VOB file contains both an MPEG-2 video stream and a number of DD, DTS or PCM audio streams.

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Matt Close
Expert Film Handler

Posts: 226
From: Hervey Bay, QLD, Australia
Registered: Sep 2001

posted 05-20-2002 09:45 PM

TI is using PCM for DLP???? .. hmmmm .... Excuse me as I really know nothing about the DLP scene, but wouldn't it make more sense to use a relatively 'lossless' audio compression like DTS and devote as much bandwidth as possible to picture quality?

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 05-20-2002 11:43 PM

Picture quality? Since when is digital projection about picture quality?

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David Baum
Film Handler

Posts: 90
From: Brussels, Belgium
Registered: Aug 2000

posted 05-21-2002 03:35 AM

http://www.dlp.com/dlp/cinema/Specs.asp?mid=143

they say that the audio is "normally" stored as 6ch PCM 24bits

thus, not "necessarily" ...

the image is stored on 4 HD drive for a total of 72GB.

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Bobby Henderson
"Ask me about Trajan."

Posts: 10973
From: Lawton, OK, USA
Registered: Apr 2001

posted 05-21-2002 11:58 PM

A 150 minute long film with 24-bit 48kHz 6.0 channel audio would require 7.7GB of space to store the audio data (864 kilobytes per second --not bits).

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Paul Linfesty
Phenomenal Film Handler

Posts: 1383
From: Bakersfield, CA, USA
Registered: Nov 1999

posted 05-22-2002 12:31 AM

It's confusing, though, to the public about soundtrack format, as the LA Times ad has the three (SRD, DTS, SDDS) digital formats listed as playing with the DLP presentations.

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David Baum
Film Handler

Posts: 90
From: Brussels, Belgium
Registered: Aug 2000

posted 05-22-2002 03:43 AM

really confusing!

some people say that on top of the cost of a new digital projector (+ server etc), the fact that PCM is the prefered recommended "by default" sound format "irritates" Dolby and Dts and Sony (SDDS) and thus "also" explains why there so few 3DLP projectors around the world ( Lucas was shocked when he was told the low nr of 3DLP-equipped theaters ... ).
not a fact, just heard it.

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John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002

posted 05-22-2002 09:56 AM

Matt (Close), I think you're a bit confused.

PCM is Pulse-Code Modulation, and is an encoding scheme, but not a compression scheme. It is in fact just an encoding, compare it with Mu-Law or U-law, etc. So if you're looking for "lossless," PCM certainly is that.

DTS does in fact use compression.

In DLP, basically your storage space is huge, so there is really no reason to worry about compressing the audio -- any audio will be so dwarfed by the size of the video that compressing it or not compressing it is probably irrelevent.

Furthermore, just because it's PCM doesn't mean there isn't compression being applied to it (though it probably means that it is lossless compression, if anything).

--jhawk

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