Resolution Confusion: It Never Ends
About a month ago, we received an e-mail from a PRO AV reader that decried the way display manufacturers often diverge from established video standards when coming up with imaging resolutions for new projection and direct-view displays. There's so much emphasis on 1080p resolution that it would always seem the best way to go?at first glance. But the devil is always in the details.
About a month ago, I received an e-mail from a Pro AV reader that decried the way display manufacturers often diverge from established video standards when coming up with imaging resolutions for new projection and direct-view displays. The reader's rant arose out of difficulties in specifying a new widescreen projector and screen for a client. Why would this even be an issue? Everywhere you look these days, you see widescreen LCD and plasma TVs, widescreen notebook computers and desktop LCD monitors, and even widescreen GPS units. There's so much emphasis on 1080p resolution that it would always seem the best way to go–at first glance. But the devil is always in the details.
While it's true that all new notebook PCs are equipped with widescreen LCD displays, there are still plenty of XGA warhorses that aren't ready to be put out to pasture. Need proof we're still living in a 4:3 world? Check out any technical conference or symposium–even those involving cutting-edge market sectors such as computers, television, and telecommunications–and you'll inevitably find a 4:3 projection screen and high-brightness XGA projectors, just waiting for all of those older laptops.
As a frequent presenter at technical conferences and trade shows, I run into this situation constantly. To make matters worse, I made a decision three years ago to format all of my PowerPoints in widescreen. Aspect ratio mismatches are further compounded by signal compatibility problems with most older projectors–and some new ones, too.
My three-year-old Acer Aspire notebook employs a 1280x800 (WXGA) LCD display, but good luck finding older projectors that will recognize and correctly size it. Even some new projectors with 1400x1050 (SXGA+) resolutions can't lock up the native signal correctly, forcing it into XGA (1024x768) mode when "hot plugged." As a result, I often find myself reformatting my slides to 1024x768, or switch the Acer's video card to 1280x720 output resolution to at least retain the widescreen format. Even that solution doesn't always work right.
Once at InfoComm, one of my larger classes was set up with a native WXGA (1366x768) high-brightness LCD projector that would not accept 1280x768 RGB signals. Everything my laptop sent out was forced back to 1024x768. The only thing that did work, after much trial and error, was 1280x720 RGBHV. Think about it: a projector with native WXGA resolution that could not show a WXGA signal.
Backwards compatibility with newer widescreen notebooks is just one headache. How about deciding which screen to install? 16:9? 16:10? (Believe it or not, there are now native 17:10 [1366x800] installation projectors available.) The logical answer is to determine what's going to get more screen time: PC sources or video sources.
I say this because, while there are many models of medium-to-high-brightness 16:9 (1920x1080 and 1280x720) widescreen projectors currently on the market, they're not all user-friendly to widescreen PC standards. In fact, I've tested projectors that refuse to accept any widescreen PC signals at all–the only thing that gets through is 720p or 1080p RGB.
On the other hand, the new crop of WXGA projectors that started coming ashore last year are much better suited to handling a wide range of conventional and widescreen resolutions from PC and video sources. These projectors typically feature 1280x800 resolution, which means they'll map XGA and 720p content pixel-for-pixel, while resizing SXGA+ with just 24-percent compression.
This doesn't mean you're out of the woods with signal compatibility problems. I recently spoke at a higher education line show, sponsored by a major projector manufacturer. I dutifully prepared my Power-Points in 16:10, using the manufacturer's template. When I arrived at the event, I connected my laptop to a brand-new, fully-loaded, high brightness WQXGA (1920x1200) large venue projector that was lighting up a 12-foot diagonal screen. I set my output resolution to 1280x800, and figured I was all set. Not!
No matter what the technicians adjusted, they could not fill the screen correctly with the native 1280x800 signal from my laptop. Every option was engaged, the autosync circuit was exercised, and we even tried configuring the image manually by changing the clock frequency, along with horizontal and vertical image shifting. (I even shook my fist and made some cutting remarks about the projector's parentage–nothing.)
Having gone down this dead end before, I decided to cut bait, calling off the techs, and switching my laptop's output resolution to 1280x720. Bingo. My slides appeared in the correct aspect ratio with small black bars along the top and bottom.
Years ago, I had a client whose favorite saying was, "Whatever happens, you lose." While that may be a bit extreme, I'm often reminded of that gem as the transition from 4:3 to widescreen imaging continues. Right now, it would appear the safest choice for a new widescreen projection system in a classroom or conference room isn't necessarily the best choice aesthetically. It's the one that will actually work the first time out. That means specifying a 16:10 screen and living with slight letterboxing of HD video content.
It also means installing a 1280x800 or (if budget allows) a 1920x1200 projector that's been tested to ensure it will correctly show native 16:10 content without any pixel-clock sleight-of-hand. With a 1280x800 projection system, you'll be smack in the middle of Resolution Road for just about any video signal source–old or new. Ever seen Composite video on a 1920x1200 system? Echh.
InfoComm Educator of the Year Pete Putman is a Pro AV contributing editor and president of ROAM Consulting in Doylestown, Pa.