New Paths for Light

Texas Instruments and Hughs-JVC shed new light on digital film exhibition.
On July 18, 1999, audiences in four U.S. theaters witnessed a revolution in feature film exhibition watching a movie without film. For four weeks, digital projections of The Phantom Menace were presented at theaters on each coast: the AMC Burbank Media Center 14 in California and the Loews Meadows 6 in Seacucus, New Jersey. Both houses utilized Texas Instruments Emmy-winning Digital Light Processor (DLP) in a prototype projector. Meanwhile, at the Pacific Winnetka Theater in Chatsworth, California and the Lowes Cineplex Odeon in Paramus, New Jersey, the Hughes-JVC Corporation exhibited its own Image Light Amplifier (ILA) 12K Projectors.
These presentations—held by Lucasfilm, THX, CineComm, Texas Instruments (TI) and Hughes-JVC—mark the potential for a drastic change from the distribution paradigm as it currently exists. Despite all the hype you hear about digital projection, says Phantom producer Rick McCallum, this technology represents the first real step forward for filmmakers who care about the way audiences see their work. For over 20 years, Lucasfilm and THX have dreamed of the day when viewers could see a film without any loss of image quality throughout its entire theatrical run.
To create the digital Phantom that was used for these presentations, an interpositive was struck from its master negative and transferred to D-5 HD tape at Modern VideoFilm in Burbank, California, under the supervision of THXs principal video engineer, Dave Schnuelle. Two transfers were done, each optimized for the respective projector systems. Colorist Skip Kimball corrected the transfer for the TI projector, and Greg Garvin colored the Hughes-JVC transfer. Both were done on a Spirit DataCine in 8-bit 4:2:2 at 1920 x 1035 resolution. That data was then compressed by the Panasonic D-5 recorder at 4:1 to 1280 x 1024. The D-5 tapes were brought to International Video Conversions in Glendale, California, where a screening room with a 24' screen was set up with three projectors: a standard 35mm rig, TIs DLP, and the Hughes-JVC ILA-12K. The movie was then compared and corrected to get [both telecine transfers and the film print] looking as close as possible to each other, submits Robert Lemer, who represents CineComm Digital Cinema, a company positioning itself to be a satellite delivery service from distributors to exhibitors with digital projectors.
The final HD data was transferred to Pluto RAID disk arrays (consisting of 20 18-gig drives) for presentation at the four theaters.
CineComm represents a key component in the proposed digital distribution paradigm. Were in a position to replace the labs and [the shipping company] in the delivery of films to exhibitors, maintains Russell Wintner, CineComms co-founder and chief technical officer. The film will be given to us by the studio, after which well compress and encrypt it, uplink it to the satellite and address it down to theaters. There, the information will be stored on our Theater Management System, a RAID array totaling about 350-400 gigs that will handle 10 to 12 screens.
The compression algorithm—at 50:1—is a proprietary development by QualComm. It uses an adaptive block size, whereas current MPEG and JPEG algorithms have a fixed block size. That allows our compression to be much more efficient because it compresses an entire frame without regard to the frame before or the one after, as opposed to MPEG, which compresses information based on the differences between the frames. The inherent difficulties of current compression technologies—such as motion artifacts—are eliminated.
The Hughes-JVC ILA-12K projector is based on liquid crystal Light Valve (LV) technology designed by Dr. William Bleha, Hughes-JVCs vice president of engineering. The LV is a spatial light modulator that accepts a low-intensity light image and converts it, in real time, into an output image with light from another source. In the case of the 12K, the other source is a 7.4K Xenon bulb, and the initial low-intensity information is derived from three infrared CRTs—one for each red, green and blue channel. Each CRT raster is imaged onto its corresponding ILA-LV through a relay lens. The Xenon beam is separated into its primary hues with dichroic mirrors, and each beam is linearly polarized by a McNeille-type polarizing beam splitter (PBS) before reaching the ILA-LV. The two sources are compounded together and focused through a lens onto the screen. The raster range of the CRTs can be altered to project different aspect ratios, from 1.33:1 to 2.4:1. At present, the ILA-12K is a 60Hz, 30 fps projection incorporating 3:2 pulldown. The company can later adapt to a 24 fps progressive scan.
The TIs DLP projector incorporates a theatrical lamp housing with their Digital Micromirror Device (DMD) technology, a semiconductor microchip with an array of 1,300,000 tiny aluminum mirrors (SXGA) that act as optical switches by rotating mechanically to reflect light toward or away from the projection lens. The DLP mounts to the front of the lamp housing, and works off the illumination from that source. The light is projected into the DLP, split dichroicly into its three primaries, and then reflected onto one of three DMDs (one each for red, green and blue). A microchip receives information from the hard disk array and coordinates the 1.3 million mirrors, updating their positions. Basically we have a memory under the mirrors, and we load that memory up to 50,000 times per second explains Paul Breedlove, TIs program director for digital imaging. We put a frame of data [from the hard drive] in the memory and break it down into pixels to determine the hue and intensity of each pixel. That hue and intensity is presented by varying the amount of time that the specific mirror is on or off during the period of that frame. The DMD may turn a mirror on and off up to 50,000 times in 124th of a second to get the color shade it needs.
With our technology, Breedlove continues, progressive and interlace doesnt have any relevance. We show an entire frame at a time, 24 fps. There is no scanning going on, so you dont see scan lines. The DLP Projectors have a native resolution of 1280 x 1024, and the 2.35:1 aspect ratio for the presentation of The Phantom Menace was achieved through an anamorphic projection lens.
This revolution is no different from just five years ago, when digital nonlinear editing arose, submits McCallum. The opposition to that was tremendous, but five years later, every studio and every television station has changed their minds. I know [accepting digital projection] is going to be challenging, but the truth is that the future is here—it’s now.