Who Specifies Digital Cinema?

by Michael Karagosian
©2009 MKPE Consulting LLC All rights reserved worldwide
originally published in the 15 May 2009 issue of Digital Cinema Report

The film industry has relied on the stability of the 35mm platform for over 110 years. Over this time, frame rates have been altered, picture size and (in some cases) compression varied, a variety of sound formats were introduced, but, for the most part, the dimensional width and perforation pitch of the film remained intact. We take for granted that one can thread an older film in a projector and get image and sound. This stability of technology was achieved without need for voluminous specifications and compliance testing. We will miss those days.

Film allowed innovation while retaining a fair degree of backwards compatibility. A compressed image might require a different kind of lens to reproduce correctly, but the core projector remained. The flexibility of film allowed the innovation of sound to emerge, an innovation that the creators of film technology had not envisioned. Certainly, they never envisioned digital sound tracks as we regularly distribute today.

This stability came without a lot of pain, largely because the industry relied on dominant manufacturers to champion its standards. In the industry's early days, Lumière and Edison set the norm. In more recent times, the industry looked to companies such as Dolby Laboratories to establish continuity for film sound. If standards bodies were employed, it was after the fact, largely to memorialize the work performed. The idea of dominant companies governing technology is not unique to the film industry, though. Consider the desktop computer, where two manufacturers of incompatible operating systems dominate 99% of the market, and where interoperability of software only exists within the domain of each of the dominant players.

Digital cinema, however, brings with it a new era of extensibility not experienced with film. No one company is responsible for developing this format. The Society of Motion Pictures and Television Engineers, or SMPTE, to date has published 26 standards to describe the digital cinema format, all produced by a committee that has over 300 registered members. Some of these standards still have some polish to be applied, and more standards are needed to bring full interoperability to digital cinema. But standards are only one step in the process of documenting how things should work. Specifications are needed.

It's important to note that SMPTE is not a specifications body. SMPTE can standardize competing technologies, for instance, and indeed, in the case of 3-D digital cinema, it nearly did. This is not unusual. A majority of standards bodies operate in this fashion, focusing on fair process over uniqueness, and keeping the door open to innovation. Specifications are needed to clearly identify which standards apply, and which don't. This is why organizations such as the Blu-ray Disc Association exist. While standards-based, the Blu-ray disc needs to be backed by a strong specification to insure that all implementations use the same technologies.

But even specifications don't guarantee interoperability. While specifications are necessary, they are still relegated to paper. When trying to determine interoperability, it takes a test to determine if a product is good, or if it's broken.

It should be no surprise, then, that the effort required to achieve interoperability in the digital world far exceeds that needed to achieve interoperability in the mechanical world. This is a tremendous distinction of digital cinema from film. The high degree of complexity and flexibility in behaviors that are characteristic of digital technology, more often than not, interfere with interoperability.

Addressing the specification problem, the major motion picture studios banded together as Digital Cinema Initiatives, or DCI, to generate the Digital Cinema System Specification, a document over 150 pages. It is backed by the DCI Compliance Test Plan, which is over 550 pages. The test plan describes the tests required to ensure compliance to the specification. While many of the tests check for adherence to the specification, they also test for the ability of products to accept content produced within an acceptable range of implementation. Equally important, testing with wrongly produced content is needed to learn if the product's behavior conforms to the specification. The combination of the specification and testing documents, and the actual product testing that result from the test plan, are important and necessary steps to insuring interoperability of digital cinema equipment.

We're not out of the woods, however. While the DCI specification addresses a lot of things digital cinema, it doesn't address everything. The audio formats described in SMPTE 429-2, for instance, are not included in DCI. Importantly, 429-2 addresses hearing impaired and visually impaired narrative audio tracks. DCI does not include 429-12, which addresses how closed caption files are to be delivered in the digital cinema package. Issues such as the logistics of relaying the digital security certificates stored inside of servers and projectors to 3rd party entities for the creation of movie security keys are not addressed. How security keys themselves are relayed into theatres is not addressed. It takes more than standards to ensure that such methods and procedures are implemented in an interoperable manner: specifications and testing are needed, too.

Are these areas that DCI will address in its specification? My bet is "no." The primary concern of DCI's members is uniform delivery and security of content, and this is largely achieved in their specification and test plan. It's time for the industry to step up to the plate. But the question is who? Without a dominant company that oversees this technology, who will champion this work?

This is a key question that remains to be answered. Even if certain companies agree to work together today to solve these problems in uniform ways, it will take more than lip service to insure interoperability in the years to come. In an industry that is accustomed to having "others" provide its technology leadership, we're about to learn that there isn't an "other" to turn to.