Electronic Cinema: The Need for Interoperability
by Michael Karagosian
© 1999 MKPE Consulting All Rights Reserved Worldwide
Published June 1999 in Systems Contractor News
While much talk has been given to recent advances in video projector technology and the
potential for server-based playback of media in cinemas, not much has been said concerning
the nature of the products that will make up the systems in Electronic Cinema. The
introduction of server-based technology to cinema systems implies networked distribution
of media signals and control and monitoring communication. New technologies will be
developed to meet the security and maintenance requirements of electronic cinema. It is
important at this early stage to push for an interoperable architecture that will
encourage competition and not create monopolies around particular product areas. Without
competition, much of the potential for electronic cinema will be lost.
Let's look at the
system architecture itself to better understand where a closed architecture should be
avoided. Many of the areas discussed are areas where SMPTE standards activity could
benefit the industry.
In the server-based system architecture, a central storage bank becomes the electronic
repository for all media shown in the cinema. Both video and audio signals emanate from
the server to the screen projectors and sound systems.
Figure 1. Block Diagram of Media Server
From the audio perspective, the server concept replaces the need for the complicated
cinema processor. A much simpler speaker processor will replace it, supplying gain
control, active crossovers and equalization. The recent trend in cinemas to place
amplifiers behind screens will lead to the placement of the speaker processor behind the
screen as well.
Out of physical necessity, film storage methods such as platters have been located near
the projector. Sound equipment has also been located near the projector since the sound
storage medium is usually the film itself. Obviously, in the electronic cinema, the need
for physical proximity of source and projector or speaker processor will no longer be the
case. Though early retrofit systems will likely have their components physically close,
the model of choice should be server-based. The transmission of media data to the
projector and speaker processor should use the same technologies both in the
physically-close model and in the server-based model.
Figure 2. Screen System Block Diagram
Video compression needs special consideration for quality, acceptable storage
requirements and security. Certainly, electronic cinema should be perceptibly different
from consumer formats. Standards regarding aspect ratios might be considered.
Multichannel audio is not new to the industry, as the film industry has a rich
history of multichannel audio formats. Existing digital multichannel formats are limited
in channel count by their storage mechanism, that being either data bits on film or on
CDROM. A new storage method should support at least 12 channels of audio to bring
flexibility to future productions. Compression is expected but should be light to ensure
Special effects have been introduced on occasion to the viewing audience. New
digital storage methods should provide space for control data that would trigger future
Sophisticated automation and remote monitoring have not always been a
consideration in the design of current products available in the cinema world. With a
networked, all electronic format, networked automation and monitoring will allow
sophisticated remote on-screen consoles to be developed for entire complexes. The same
technology can provide a means for remotely located maintenance personnel to monitor the
health of the systems. The result should be improved consistency in quality in the cinema.
Security of the video signal is of prime importance to the system. The system
itself has to be intrinsically secure without the need for any support from the theatre
owner. For the video signal, that means an encoded signal that requires a key to decode.
Keyed security is not new to the industry as similar security is performed today with the
DTS audio CDROMs distributed around the world. It seems prudent that the same keyed
encoding method used to store the video signal also be used to transmit the signal to the
projector and speaker processor, providing a fully locked signal path.
Figure 3. Block Diagram Showing Transports, Decoders,
and Keys Interoperability
The system architecture and the system requirements identify the areas where
technologies have to be developed, or at least standardized, to have interoperable
products. These are:
- Video compression and secure decoding
- Audio compression and secure decoding
- Transport for encoded video from server or playback unit to the projector
- Transport for encoded audio from server or playback unit to the speaker processor
From the control and monitoring aspect, these areas should also be addressed:
- Video projector control and monitoring
- Audio speaker processor control and monitoring
- Server control and monitoring
To prevent splintering of the industry over the choice of these technologies, a
"committee of experts", usually meaning a standards body, should stand behind
the choices. The technologies chosen may be proprietary, but should be made uniformly
available to those manufacturers who choose to license them. Ownership of a technology
should not become the means for building a monopoly, or a near monopoly, at the product
level. Monopolies stifle innovation, and innovation is what keeps this industry alive.
I have had considerable experience with the standardizing of control methods through my
experience in the AESSC. My suggestion for control methods is that standard protocols not
be considered. Instead, a combination of software technology and transport technology
should be standardized. IP transports have proven their utility in the network world, and
are supported by a large body of knowledge that can be readily tapped. The technology
provided through Microsoft's ActiveX Controls or Sun Computer's JavaBeans should be relied
upon so that innovative, custom displays can be easily created by third-parties both for
use in the cinema and for use by remote maintenance technicians.
For the implementation of electronic cinema, there are several areas of technology that
should be standardized by an organization such as SMPTE. The results of standardized
technology will be interoperable and innovative products that will promote competition and
provide users with quality choices.