Direct view LED screens: Taking the lead for DCI?

Direct view LED screens: Taking the lead for DCI?

Technological evolution in digital cinema led to the creation of the Digital Cinema Initiatives. Now, nearly two decades on, further innovation has prompted a raft of new specifications. Gary Feather, CTO at NanoLumens, creators of LED visualisation solutions, examines developments.

FOR ANYONE THAT WORKS in the cinema industry or the digital display industry, it is more likely than no that they will have heard the acronym “DCI” floating around. DCI isshorthand for the Digital Cinema Initiatives, LLC, a united endeavour from several of Hollywood’s biggest studios, aided by visionary thought leaders from the movie-making side and brilliant technical experts from the technology side.

The DCI venture exists, in its own terms, “to establish and document voluntary specifications for an open architecture for digital cinema that ensures a uniform and high level of technical performance, reliability and quality control.” In other words, DCI wants to standardise digital cinema requirements so that content is created and displayed uniformly and at as high a level as is practically possible.

The studios involved in the formation of the DCI were Metro-Goldwyn Mayer, Paramount Pictures, Sony Pictures Entertainment, 20th Century Fox, Universal Studios, The Walt Disney Company, and Warner Bros. Dolby is involved as well.

The origins of DCI

The impetus to create a cooperative body between the biggest movie studios was initiated by Tom McGrath, who at the time was an executive with Paramount. McGrath had held several influential positions in a few major studios by the time he reached Paramount and he held nuanced views on how the industry might evolve. Now a seven-time Tony Award winner, McGrath had always fostered an appreciation for the vividity of live performance. This liveliness was something he felt the film industry had yet to capture, and so, in 1999, McGrath applied to the US Department of Justice for anti-trust waivers so that his studio could work with others to create more true-to-life films. Digital Cinema Initiatives, LLC was formed just a short time later in March 2002, marking the beginning of the end for traditional film as a medium for presentation.

The intimate tether between the abovementioned studios and DCI makes conformance to DCI specifications a virtual (though still technically voluntary) requirement by software developers or equipment manufacturers targeting the digital cinema market. Their message is clear: this is the direction cinema is going, it’s time to get on board.

The direction of DCI

Evidenced by the rise of luxury cinemas, customers have indicated they are willing to pay a higher price for an elevated experience. The premium segment is the fastest growing portion of the cinema market, but display performance has failed to keep up. This is where DCI fits in. Dramatic improvements off screen have not been mirrored on it. Arguably, traditional display methods leave limited headroom to do so. While almost 200,000 DCI-compliant projectors (most of which are DLP-based) have been sold since 2002, the technology solution many see as headlining the future is direct view LED; an emissive not reflective projection technology. Newly unveiled LED technologies are capable of brightness levels more than 10x stronger than any projector, with the ability to capture deeper blacks too.

Unlike a projector, which obviously projects full images onto a screen, images on LED screens are comprised of thousands of individual light-emitting diodes each generating colour and brightness. An LED display can create true blacks simply by turning off diodes, producing zero nits; a projector, which must project some light, cannot. This ability to hit brighter and darker signatures expands an LED display’s dynamic range to a point where DCI-compliant direct-view LED displays can accommodate HDR video and support PQ levels from Dolby. By exposing images multiple times, HDR technology attempts to make digital images more true to life with greater bit depth in shadowy areas and in blownout bright areas. In other words, a camera records the same image at different exposures and brightness and software blends them. It can make films appear more lifelike.

Giving audiences an experience that vividly mirrors what they might see in the real world is a mission DCI is committed to. Direct view LED is the next step towards that objective.

The road ahead won’t be without its bumps however. As a leading provider of direct view LED display solutions with an eye towards their cinematic use, NanoLumens knows well that while digital cinema has come along impressively, there are still challenges facing the primary actors in this drama.

What’s new in the DCI specs?

The DCI released a “Statement on Technology Evolution in Digital Cinema” in March, giving further background on its draft specifications on HDR and direct view displays (released in November last year). This update, “DCIx”, aims to account for the new visual capabilities of emissive LED displays, including more challenging targets for peak luminance, uniformity, colour space, diffused and spectral reflectivity, contrast ratio, and a range of other performance metrics.

While the specifications focus mostly on visual output, another field of DCI specifications concerns how content is secured. In fact, 65% of DCI compliance relates to security, the rest covering image quality. Transitioning films from physical reels to digital reels eliminates logistical expense, but renders content susceptible to security breaches. DCI specifications govern security of studio vaults where films are stored and the integrity of how films are sent out, but they also dictate how content is received. Movie data is received by media blocks: a secure physical part of the device playing the film, be it a projector or LED display. Manufacturers of such blocks face DCI compliance testing — all this testing can be a drag on progress, but it is imperative to the DCI’s greater mission that cinema quality is beyond compromise. Insiders believe the digital market may expand rapidly with a shift from DLP to LED and DCI to DCIx.

Transitioning cinema onto direct view LED will alleviate many issues, raising the ceiling of the moviegoing experience beyond its current capability. It may take time, but DCI exists not simply to improve cinema now but also to expand where cinema goes in the future. The ideal experience is of a story well told and LED canvases are fast advancing how it’s done.

Specifications: learn to walk before we run

Currently, only a few companies perform DCI compliance testing. Each of these labs tests just two or three display systems a year over the course of a 20-30 week test period at a cost of around $200,000. Tests are based on each lab transforming their knowledge with DLP chips, projectors and screens, and they do not yet test for more advanced HDR10, HDR10+, and Dolby Vision specifications. Technology evolves faster than our ability to standardise and certify it — digital cinema is still proving it can walk before it runs. However, DCI is working tirelessly to bring highly desired images to moviegoers. Current specifications give guidance on creating a DCP from a collection of files — the Digital Cinema Distribution Master (DCDM) — as well as the specifics of content protection, encryption, and forensic marking. Specifications also establish standards for decoder requirements and the film presentation environment itself, such as ambient light levels, pixel aspect and shape. Even though it dictates what kind of information is required, the DCI spec does not include details about how data in a distribution package is formatted. Formatting of this information is defined by the Society of Motion Picture and Television Engineers (SMPTE). Both the industry and the technology are complex — total uniformity requires painstaking attention to detail. Specifications will only grow more detailed as time goes on.