Those of us who’ve spent a lot of time reviewing movies on video discs (from Blu-ray to DVD and, for some of us, even back to Laserdisc) understand that the process involves its share of both objective and subjective criteria. The exact balance varies depending on the content under review. Every movie—and every disc—is unique. Nonetheless, certain rules and standards hold true in most circumstances. While Blu-ray Discs provide vastly better quality than DVDs, and we in turn have gotten a lot savvier over the years in detecting the nuances of what makes a good or bad video image, the fundamental process has remained unchanged in the transition from standard definition to high definition. That is, until now. The introduction of 3D has thrown things for a pretty big loop. The more 3D content I’ve watched (on Blu-ray or other sources), the more questions I have about exactly how 3D should be evaluated. It turns out that reviewing 3D is a lot trickier than reviewing standard 2D.
The daily deluge of news into my inbox included a very sad item yesterday. Insight Media, a display-industry analysis firm, reported that Samsung will not be making so-called "active retarder" 3D LCD TVs in collaboration with RealD. This approach places an active polarization-switching layer over the LCD layer, much like the polarization switcher placed in front of a projector lens in a commercial RealD theater. The viewer wears standard passive glasses, and the TV quickly alternates the polarization in sync with the alternating left and right images on the screen.
If you're shopping for an HDTV this weekend, you might find yourself battle-scarred by a war you didn't even know was happening. Anyone considering a set with 3D compatibility—which now comes along for the ride in most better flat panels —will be forced to choose between one that comes with either active-shutter or passive 3D technology. The key proponents of active-shutter 3D are Samsung, Panasonic, and Sony. Leading the charge for the more recently introduced passive technology are Toshiba, Vizio, and LG (which developed the passive home 3D system being used by the others). Although both types will play back the same 3D Blu-ray Discs and broadcasts, the glasses and the resulting 3D image are different. Here are some facts to help you sort things out.
In addition to the news that RealD has partnered with Samsung to make so-called active/passive 3D flat panels, the company had some other interesting announcements and demos at the SID conference this week. For example, even though RealD is known mostly for passive-polarized 3D glasses, it has also developed universal active-shutter glasses that work with any manufacturer's active 3DTV.
This week, the Society for Information Display (SID) is holding its annual DisplayWeek confab at the Los Angeles Convention Center, where the future of display technology is front and center. Among the biggest announcements at the show was a partnership between Samsung and RealD to develop a new type of 3D flat panel that uses passive glasses but does not cut the vertical resolution in half like other passive-3D flat-panel technologies.
Aside from the RealD passive/active 3D flat panels, Samsung had some other great demos in its booth at SID DisplayWeek. One of the most interesting was a 70-inch, 240Hz, 4K (3840x2160) 3D panel that uses active-shutter glasses. The custom footage of a woman hanging out at an oval house in the woods looked gorgeous, though all the motion was very slow, and I did see a few artifacts in the stairs during one pan.
Up to the present, all 3D HDTVs have used active shutter glasses, and most still do. The two separate 3D images—one for each eye and each of them full 1920-by-1080 resolution—flash on the screen in sequence. Active shutter glasses are triggered by an IR signal generated by the 3DTV (or a separate transmitter attached to it). To isolate the 3D images to their respective eyes, the glasses alternately open and close each eyepiece. The alternating is rapid enough that even though the two pictures are displaced in time, the brain fuses them together and sees them as a single 3D image.
Last Friday, video guru Joe Kane visited Grayscale Studio, where Tom Norton and I conduct most of our display reviews, to show us his latest test patterns, which are designed for 3D displays. The images were generated by a VideoForge test-pattern generator from Audio Video Foundry and sent to an Accell HDMI switcher/splitter, which fed two flat panels—a Samsung UN55D8000 with active glasses and LG 55LW5600, which uses passive glasses. (Interestingly, the Accell switcher/splitter can pass 3D from the VideoForge, but not from a 3D Blu-ray player.) The results of these tests were very interesting, to say the least.
Tom Norton and I saw Rio in 3D last week at our local AMC multiplex, which offers something called Enhanced Theater Experience (ETX) with a larger screen, digital projection, and a beefier sound system. I guess this is somewhere between a conventional theater and Imax, and it was quite good overall.
As far as I have understood up to now, a passive-3D LCD flat panel displays 3D Blu-ray images in the following manner—the odd-numbered lines of left-eye information are displayed in the odd-numbered lines on the screen, and the even-numbered lines of right-eye information are displayed in the screen's even-numbered lines. As a result, the TV simply discards the undisplayed lines and each eye sees a resolution of only 1920x540 pixels. However, the image on such TVs that I've seen looks sharper than this would seem to indicate, though I do normally see thin, black horizontal lines, especially if I'm too close to the screen. The explanation I've heard most often is that the brain fuses the two images into one 1920x1080 3D image, but LG tells a somewhat different story.
One of the clearest trends at NAB was the dramatic drop in the cost of creating 3D content, bringing this capability within reach of hobbyists and wannabe stereographers. Sony showed two inexpensive 3D camcorders, the HXR-NX3D1 ($3400, available this Summer, shown above) and HDR-TD10 ($1500, available end of April). Both record 1920x1080 in AVCHD format to internal memory (96GB in the NX3D1, 64GB in the TD10), and they have a dual-format slot that can accept Memory Stick or SD memory cards. They can also copy files directly to a hard-disk drive from a USB port with no need for a computer. The TD10 records at 60i (60fps interlaced), while the NX3D1 can record at 60i or 24p. The only other difference is that the NX3D1 provides XLR audio inputs and generates time code.
I received an e-mail on the last day of NAB announcing a demonstration of a new glasses-free 3D display technology from a company called 3DFusion, so I had to check it out before heading back to L.A. The company has licensed some 800 related patents from Philips and developed its own algorithms to solve the problems of limited viewing cones and crosstalk while using a lenticular filter on a flat-panel screen.
Yesterday, I ran into David Reisner, digital-cinema consultant and recent guest on my Home Theater Geeks podcast, who told me about an exhibitor called Volfoni, which is showing hybrid active/passive universal 3D glasses at NAB. Intrigued, I sought them out.
Today, I attended a couple of sessions on 3D in what is called the Content Theater. The material was displayed from a Sony 4K digital-cinema projector using a dual-lens RealD polarization system projecting different 2K sections of the imager for the left and right eyes. The polarization-preserving, perforated screen was from Harkness and measured 24x13 feet.
One of the sessions in the Content Theater was presented by 3net, the 24/7 3D channel co-created by Imax, Discovery Channel, and Sony and currently available on DirecTV. In addition to the big projected image, six 42-inch Sony monitors located along the walls were showing the same content so we could see what it looks like on a typical home display, for which 3net's original content is designed.
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