Digital Cinema Frequently Asked Questions (FAQs)

What is DCI?

DCI is the abbreviation for Digital Cinema Initiatives, an organization whose owners are the six major motion picture studios (the same six studios that also comprise the MPAA). In July of 2005, DCI issued version 1.0 of its Digital Cinema System Specification, representing the consensus of DCI's members in regards to many technical details of digital cinema. The DCI specification can be thought of as the professional cinema equivalent of an agreement to exclusively use either the HD-DVD or Blu-ray consumer formats. The DCI specification is not a standard, however, it is significant input to the standards process. Standards for digital cinema are the domain of the Society of Motion Picture and Television Engineers (SMPTE). A copy of the most recent DCI specification (v1.2) can be downloaded from the DCI website. The latest version incorporates over 200 errata issued since the original release of the specification in 2005.

What does "DCI compliant" mean, and which products are DCI compliant?

"DCI compliant" is a term used to describe products that conform to the DCI specification. At the time of this writing, no products on the market are fully "DCI compliant." The "standard" used to determine suitability of installations is set by an informal process called "Interop." The earliest the "Interop." expects to achieve DCI compliance is Spring 2009. That would be the earliest that tested, interoperable, DCI-compliant products will be available. However, it is likely that the process will take until October 2009, possibly longer.

DCI published v1.0 of its test plan, as developed by Cinecert. However, DCI has not announced how the test plan will be utilized. No arrangements have been made with 3rd party testing agencies to implement the test plan, and no plans for testing digital cinema products have been discussed with manufacturers.

Even with an implementation of the test plan, there unfortunately will not be a central authority that determines whether or not a device is DCI compliant. Each studio will determine individually what constitutes a passing mark, which will produce less than uniform results.

It's noteworthy that the term "DCI compliant" is not trademarked and there is no mechanism for managing the use of the term. Anyone can claim their product is DCI compliant, so buyer beware.

Are the digital cinema standards finished?

15 standards were published by the The Society of Motion Picture and Television Engineers (SMPTE) by Dec-2007. Some 20+ drafts are either in progress or remain to be started. Further, some standards may need to be revised as experience in the field is gained with real products.

Missing from SMPTE distribution standards are audio and closed captions. A default audio format is underway in SMPTE, but the full "flexible" audio standard has yet to be started. Work is underway for closed captions. A full suite of distribution standards is not expected until end 2008 or early 2009. Note that the full suite of distribution standards will not include interoperability of digital cinema players, or automated key delivery. Those standards will take longer.

What are NATO's Digital Cinema System Requirements?

NATO's Digital Cinema System Requirements (NSR) describe the needs of the exhibition industry. Combined with the DCI specification, it provides a complete set of digital cinema requirements to standards committees, service providers, system providers, and manufacturers. The most recent release of NSR is version 2.0. NSR describes the use of networks, automated key delivery, facility numbering, theatre management system functionality, maintenance logs, and much more. It can be downloaded from the NATO web site.

How do I know if a product follows the latest SMPTE standards and/or NATO's Digital Cinema System Requirements?

There is no mechanism to learn if products meet SMPTE standards, or if they meet NATO's Digital Cinema System Requirements. It is recommended that those buying equipment refer to the relevant standards in their purchase specification. Note that simply asking for "DCI compliance" does not guarantee that ALL SMPTE standards are met, and will not guarantee that NATO's Digital Cinema System Requirements are met.

How do I know if a product is interoperable with others?

Simply stating that a product meets SMPTE standards does not guarantee that the product is interoperable with other products that claim the same thing. To achieve interoperability, product manufacturers must informally work together. Thus, interoperability is achieved in stages through partial implementation of SMPTE standards - this is the so-called "Interop" process. More on this topic in the discussion on DCI compliance.

Where can I learn more about Inter-Society's ISDCF?

Inter-Society is an organization chartered to socialize issues across the industry. It is not a standards effort, nor is it a compliance or certification effort. However, it is an excellent organization for socializing issues and solutions. More can be learned about the Inter-Society's Digital Cinema Forum (ISDCF) at the ISDCF web site.

What is the difference between 4K and 2K projection?

"4K" is the term used to describe images that have approximately 4K vertical lines. In digital cinema, a 4K image with a 2.39:1 ("scope") aspect ratio is delivered having 4096 x 1716 pixels. A 4K image with a 1.85:1 ("flat") aspect ratio is delivered having 3996 x 2160 pixels.

"2K" is the term used to describe images that have approximately 2K vertical lines. In digital cinema, a 2K image with a 2.39:1 ("scope") aspect ratio is delivered having 2048 x 858 pixels. A 2K image with a 1.85:1 ("flat") aspect ratio is delivered having 1998 x 1080 pixels.

Are 4K projectors available today?

Yes, under 100 auditoriums have installed Sony 4K SXRD projectors.

Do I need a 4K projection system to play a 4K movie?

No, 4K movies can be played on 2K projection systems. Through the use of JPEG 2000 image compression technology, a 2K projection systems can extract a 2K image from a 4K digital movie. Likewise, a 4K system can increase the resolution of a 2K image for projection on a 4K projector. This capability results in full interoperability between 2K and 4K systems, allowing a studio to deliver "single inventory" content (i.e., either 2K or 4K) with confidence that the movie can play on both 2K and 4K systems.

Can I use a single lens to project both scope and flat images?

According to NATO's System Requirements 2.0, yes. But some studios say no. The DCI specification prefers, but does not require, the use of separate lensing to project scope and flat images. This was requested due to the belief that the scaling engine used to resize images inside the projector was not of high quality. However, even though recent tests demonstrate that the scaling engine in the TI projector is of very high quality, some studios require that a separate lens is used for flat and scope images when side masking is employed.

Can I use an anamorphic lens on my projector?

While anamorphic lenses are the best way to make efficient use of the light available to the projector, not all studios may accept their use. (See the discussion on Single Lens above.)

Anamorphically squeezed images will not be distributed digitally, as is done with film. However, the projector can electronically perform an anamorphic re-mapping of the image onto its electronic imaging device, requiring an anamorphic lens to correctly display the image. The benefit of this projection technique is that it utilizes the full imaging chip array, taking full advantage of the available lamp power. Images projected with an anamorphic lens can light up larger screens than in non-anamorphic installations. The anamorphic projection technique can be particularly useful for lighting up large screens for 3-D presentations.

How are security keys (KDMs) delivered?

KDM is the acronym for Key Delivery Message. The security key for each movie is delivered in a unique KDM, one KDM per per digital cinema server. The security key is encrypted within the KDM, which means that the delivery of a KDM to the wrong server or wrong location will not work, and thus such errors cannot compromise the security of the movie. The KDM is a small file, and is often emailed or delivered by means of USB thumb drive. (DCI's specification requires the presence of a modem for security communications.) However, these are inadequate methods for deliverying KDMs in large numbers. For digital cinema to grow, KDM distribution must be streamlined and become transparent to operations.

How are KDMs controlled?

KDMs have only a few conditions associated with their use:

• A KDM will only work for one movie title on one server.
  
• A KDM will only work within the prescribed engagement time period.
  
• The server will only work if connected to a projector that is listed in the Authorized Device list of the KDM. (Not implemented at the time of this writing.)
  

To play a movie on two servers requires two KDMs for the movie. This means that to move a movie to a 2nd server requires a 2nd KDM. The engagement time window of the KDM is set per the business requirements of the studio distributing the movie. If your KDM expires and you don't have a new KDM to continue on the engagement, then you cannot play the movie.

To create the KDM, the digital security certificate for the server must be known, as well as the certificates of equipment in the projection booth that the equipment may operate with. The certificates are validated by the KDM creator before generating the KDM. Validation takes place by looking up the equipment on a "trusted device list."

What other conditions will cause a movie to not play?

One of the "dark screen rules" stated in the DCI specification is that equipment will fail to function when a security sub-system is tampered with. To a theatre operator, this means that the security components of your equipment must be maintained by others who are certified to repair the security components. You will have to check with the equipment manufacturer to learn who is qualified for this role.

The DCI specification also requires the playout of a movie to fail if the forensic marking capability of the server is not functioning correctly. The server's forensic marking system will mark the image and audio of the movie such that camcordered copies can be traced to the location of theft. If the marking system fails, then the server will fail to playout the movie. However, the studio can enable a flag in the security key to disable the marking system, which will also allow the movie to play with a failed marking system.

What is a Facility List Message?

The Facility List Message (FLM) carries the list of digital certificates that exist in the secure equipment a cinema facility for use by those who create KDMs. The FLM is assembled by the theatre owner's equipment, it is digitally signed by the equipment, and is transmitted by the theatre owner's system to those entities authorized to create KDMs. This information is also used to populate the Trusted Device List of the KDM. The diagram below illustrates the relationship of the FLM to the KDM.

For those cases where only a single screen is to receive a KDM, such as special authorization for a sneak preview, a "partial" FLM can be created containing the security information for one or more auditoriums. In this case, the FLM is tagged as "partial," and the purpose of the partial FLM is described in prose inside the message.

Do I always need a Theatre Management System (TMS)?

The Theatre Management System (TMS) is part of your Information Technology (IT) infrastructure, and provides a multiplex with centralized management of all screens. As to whether or not you'll need one, the answer is both yes and no. No, you will not always need a fully implemented TMS. But, yes, you will at least the Key and Data Management component of the TMS. Without this component, you will not be able to automate the delivery of keys to your screens, and you will not be able to manage logs. Fortunately, this is envisioned to be a software application that you run on a PC. However, not all vendors plan to implement it in this way.

What do I need to know about digital 3D?

Digital 3-D is a somewhat complex subject, and bears some discussion. The term "3-D" is used in digital cinema to describe stereoscopic images, where left and right images are displayed on a 2-D screen, and a method for viewing these images is employed such that each eye only sees the intended images. The result is that the left eye sees a different image from the right eye, providing the stereoscopic effect.

The distribution of digital 3D content is intended to be independent of the various methods for displaying 3D. This is not quite true today for all 3D presentation methods, but work is underway to make sure that distribution of 3D is truly independent of the method of presentation.

While there are many techniques for creating 3-D images, there are only three "add-on" technologies available for viewing them when projected by a single digital projector. The add-on technologies can be classified as those using polarized glasses, those using active "shutter" glasses, and those using spectral division glasses. See the article Choice in 3-D for an explanation of how the various 3-D add-on technologies work. Notably, all methods for projecting 3-D can display any form of digital 3-D content, regardless of how it was created. That point cannot be stressed sufficiently, as it is often misunderstood.

Three questions can be asked of each method in differentiating the methods:

• Are the glasses inexpensive enough to be given away (so that they don't require washing)?
  
• Does the method use a normal projection screen (and not a silver screen)?
  
• Can the movie be moved to a 2nd or 3rd auditorium without purchasing additional 3D systems?
  

None of the 3D presentation methods can answer "yes" to each question, making it an individual choice when determing which system best suits your needs.

A noteworthy issue of digital 3-D, which is independent of the presentation method, is the "flash" rate. The flash rate is the at which a pair of left and right images are alternately and repeatedly rendered by the projector. "Triple flash" refers to an image projection flash rate of 72 stereo frames per second, or 144 individual frames per second. Note that most DLP projectors cannot utilize the full 2K imager array when triple flash is employed, requiring that a separate lens be used.

A fourth method for projecting 3-D images is dual-projection. Dual projection is gaining interest among exhibitors as it will light up larger screens, and the cost of the 2nd projector is not much more than the cost of a 3-D add-on technology.

Can a single projector display 3-D images with full (4:4:4) color representation?

No. Single projector 3-D images are displayed in 10-bit 4:2:2 color representation. While it's true that the DCI specification calls for 12-bit color with 4:4:4 color representation for 2-D images, the specification for 3-D distribution allows 4:2:2 color representation when displaying 3-D images.

Why are current installations often labeled beta systems, and what can we learn from them?

In an ideal world, a digital cinema system would simply replace a film system, and business would go on as usual. Unfortunately, digital cinema is not that simple. In fact, digital cinema systems are significantly more complex in operation than their film counterparts, and, by design, they are capable of delivering the capability to integrate into your backoffice applications. As such, they introduce new and not well-understood constraints on business operations. Not only is there very little experience with much of the new technology specified by industry organizations (particularly with security technology), there are no products that fully implement SMPTE standards-in-progress, DCI's System Specification, nor NATO's System Requirements. Thus, today's systems are truly beta, and today's users are the early adopters whose experience will contribute to the shaping of future digital cinema systems.

What questions should I ask of digital cinema system providers?

Not all system providers approach digital cinema in the same way. Differences exist in the implementation of the Theatre Management System (TMS), the central control center for a theatre. But notably, there are differences that will affect exhibitor policies and system security. Suggested questions to ask your server provider:

• Moving the Movie
  How long does it take to move a movie from one auditorium to another?
• Central Office Reporting
  Will the system report to your central office the arrival of content and KDMs? Will it report when KDMs are only days away from expiration?
• Maintenance
  Who maintains the system? What Service Level Agreements are offered?
• Security Log Data
  The security policy in the DCI specification is "control lightly, audit tightly." A security log will likely be requested by the movie distributor. The DCI specification and SMPTE standards allows the exhibitor to remove a certain level of sensitive information from the security log. Does your system give you this ability, as well as the ability to view and approve your security logs before they're sent?
• Security of Exhibitor Networks
  The digital cinema should respect the security of the theatre owner's network by insuring that the delivery of KDMs will not compromise exhibitor network security, and that the issuance of security log data is under the exhibitor's control. Is this how the system you are considering behaves?

What work remains in digital cinema?

At its core, digital cinema relies upon state-of-the-art information technology. It is complex, and a lot of work remains, particularly in the supply chain, before digital cinema will be ready for tens of thousands of screens. Top items on the list:

• KDM Delivery
  KDMs today are delivered by email or USB stick. Some KDMs are delivered by modem. This may work for the relatively small percentage of existing cinemas that are early adopters, but it will not scale when having to deliver several movies a week for 39,000 screens in the US. The problems only get worse when attempting to deliver KDMs around the world. The lowest cost to the supply chain is for KDMs to be delivered by an automated process. A better method is needed for KDM delivery than what we have today.
• File Management
  Content distributors needs to track and confirm delivery of files, and exhibitors need to log and manage files once they are delivered. The lowest cost to the supply chain is for these processes to be handled automatically. The industry does not have a single method that allows multiple content distributors to deliver files to a theatre site and verify that their files have arrived. Similarly, theatre central office systems have no idea when digital content or KDMs have arrived, when KDMS are about to expire, or when security logs are created or sent out. Much better file management systems are needed.
• Digital Cinema Server as a Commodity
  Once installed, the theatre owner should be able to replace the digital cinema server with one made by a different manufacturer without having to install a new Theatre Management System (TMS). Unfortunately, that is not the situation we have today. Much work remains before the digital cinema server is truly a commodity.
• In-Theatre Standards
  Show playlists, show schedules, performance logs, and point-of-sale interfaces are all areas where standards have been requested. As of the date of this writing, only the Show Playlist has made its way to ballot in SMPTE DC28, but with the results that it requires further work.
• Security Log Collection
  The sharing of exhibition security logs with distributors comes from the studio policy for security management of "control lightly, audit tightly.": Sharing the security log accomplishes "audit tightly." The policy indicates that those who distribute KDMs will be responsible for collecting security logs. NATO's Digital Cinema Requirements calls for exhibitors to push filtered security logs out to business partners. However, the industry has no common procedures or standards for managing the communication of security logs.


What is the status of digital cinema today?

The installation rate slowed dramatically at the end of 2007 as the sales funnel was fulfilled. At the time of this writing, AccessIT has fulfilled its ability to sell more systems using Virtual Print Fee (VPF) financing. The industry is waiting for major US exhibitors to adopt digital cinema.



(click to enlarge)

Technology adoption cycles have been studied for over 20 years. Stagnant sales and lack of major market uptake following a successful early adopter period is indicative of what author-consultant Geoffrey Moore calls the chasm. The diagram below shows how the progress made with digital cinema maps onto the classic technology adoption curve. Digital cinema has yet to be embraced by the mainstream cinema market. However, when digital cinema advances past the early adopter stage, it is unlikely to take off quickly, as the diagram might suggest. Digital cinema is a replacement technology, not a technology that creates new revenue opportunities. Widespread adoption of this technology in the US could take 10 years or longer.



Digital Cinema Technology Adoption Curve
(click to enlarge)

Manufacturers and supply chain vendors are working hard to "cross the chasm" and bring digital cinema into the mainstream market. To get there, many issues need to be addressed, including business planning and the technical issues outlined on this page.