THE PRO PERSPECTIVE
Resolution Confusion
About a month ago, I received an email from a PRO AV reader that decried the divergent paths display manufacturers often take from established video standards when coming up with different imaging resolutions for new projection and direct-view displays. This rant arose out of difficulties in specifying a new widescreen projector and screen for a client.
Hmmm.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, even widescreen GPS units! There’s so much emphasis on “1080p resolution” that it would seem the best way to go — at first glance. But the devil is always in the details.
In order to help our clients jump into the widescreen future, we must not forget all of the legacy display formats that will still be used with that new widescreen projector or monitor, such as the tried-and-true 1024x768 XGA format (to steal from Monty Python, it’s not quite dead yet!), analog composite and S-video sources, (720x480), and even the occasional SVGA (800x600) computer.
While it’s true that all new notebook computers are equipped with widescreen LCD displays, there are still plenty of XGA “war horses” that aren’t ready to be put out to pasture. Heck, I even have a Toshiba Satellite notebook from 1998 that still runs beautifully, even though it’s limited to 800x600 output resolution.
Need more proof that we’re still very much living in a 4:3 world? Check out any technical conference or symposium — even those involving cutting-edge market sectors like computers, television, ad telecommunications — and you’ll inevitably find a 4:3 projection screen set up with high-brightness XGA projectors, just waiting for all of those older IBM ThinkPad, HP, Toshiba, and Dell laptops.
I run into this situation constantly as a frequent presenter at technical conferences and trade shows. To make matters worse, I made a decision three years ago to format all of my Powerpoints in widescreen! The aspect ratio mismatch is further compounded by signal compatibility problems with most of these older projectors — and some new ones, too.
My three-year-old Acer 5570 Aspire notebook uses a 1280x800 (WXGA) LCD display, but good luck finding older projectors that will recognize and correctly size it! Even some new models with 1400x1050 (SXGA+) resolutions can’t lock up the native signal correctly, and send display data back to my notebook that forces it into XGA (1024x768) display 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 — and even that solution doesn’t always work right.
Three years ago at InfoComm, one of my large 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. Kafka-esque, isn’t it?
Backwards compatibility with newer widescreen notebooks is just one headache. How about the decision as to which wide aspect ratio 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 is 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 SXGA+ resizes with just 24% compression.
This doesn’t mean you’re out of the woods with signal compatibility problems. I was recently invited to be the luncheon speaker at a higher education line show, sponsored by a major projector manufacturer. I dutifully prepared my Powerpoints 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 projection technicians adjusted, they could not fill the screen correctly with the native 1280x800 signal from my laptop. Every aspect ratio option was engaged, the autosync circuit was exercised a few times, 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 at the projector and made some cutting remarks about its parentage. It felt good, but accomplished nothing.)
Having gone down this dead end many times before, I decided to cut bait, calling off the techs and switching my laptop’s output resolution to 1280x720. Bingo! My widescreen slides magically appeared in the correct aspect ratio with small black bars along the top and bottom of the frame.
Many years ago, I had a client with a rather negative outlook on life. In fact, his 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 that the safest choice for a new widescreen projection system for your classroom or conference room isn’t going to be the best choice esthetically, but rather the one that’s actually going to work the first time it’s powered up. That means specifying a 16:10 screen and living with slight letterboxing of HD video content.
It also means installing a 1280x800 or (if your budget can stand it) a 1920x1200 projector that has been thoroughly tested and vetted to ensure it will actually show native 16:10 content correctly and automatically without any pixel clock sleight-of-hand.
If you need one more justification for going with a 1280x800 projection system, consider this: You’ll be smack in the middle of “Resolution Road” for just about any video signal source, old or new. (Ever seen composite video displayed on a 1920x1200 projection system? Echhhh...)
This article appears in the May 2009 issue of Pro AV magazine.
©2009 Peter Putman/Hanley-Wood
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