How Projectors Handle HD Content

August 11th, 2009

As a two-part article recently explained, there are still some important differences between “business” projectors and those intended for “home theater” use. However, some manufacturers are experimenting with product designs that join the best features of each type into a single device. Perhaps one of the last areas of divergence is the native (or “physical”) pixel count, which affects two very important specifications: (1) the resolution and (2) the aspect ratio.

Simply put, “resolution” is the number of pixels that are packed into the physical dimensions of a projected image or monitor, and “aspect ratio” is the relationship between width and height. A four-foot by three-foot image has an aspect ratio of 4:3, standard for TVs from their introduction until just a short time ago. Now, a projection screen at that ratio could display an image of 800 x 600 resolution, or there could be more pixels packed in for a higher resolution and sharper image in the same dimensions, like a pixel count of 1200 x 900. Both have the same 4:3 aspect ratio, both fit on the 48-inch by 36-inch screen, but the latter has the higher resolution. Of course, CRE rents various sizes of Fast Fold Da-Lite screens to fit all situations.

Wide, wide world

The standard SVGA (800 x 600) and XGA (1024 x 768) business projectors have a native, or built-in, aspect ratio of 4:3, as well, so the image corresponds to a standard computer screen or “regular” television. Widescreen content, such as DVDs and HDTV programming, has an aspect ratio of 16:9. The best way to handle the widescreen format is to use a projector with a native widescreen resolution, which today is more likely to be a home theater projector (although not for long). This is the only way you can avoid the image stretching, letterboxing, image cropping, or other aspect ratio adjustment techniques that make 16:9 content fit on a 4:3 screen.

Most of the basic business projectors are SVGA and are not up to the task of displaying HD images from your satellite, computer, cable tuner or other HD input. They simply do not have sufficient resolution to do the job right. The two primary HD resolution formats today are 720p and 1080i (1280 x 720 pixels and 1920 x 1080, respectively). An SVGA projector with its resolution of 800 x 600 pixels cannot display either of these formats without downscaling.

Working it out

Even DVD content, which at 852 x 480 has a lower resolution than HDTV, is a bit much for the entry-level SVGA projectors to do a good job. XGA, as its numbers indicate, has sufficient resolution to handle DVDs and can get quite close, needing only narrow top and bottom letterbox bands, to displaying 720p, as well. With just an XGA projector, screen and a laptop rental from CRE, you have a mobile presentation system that can handle a meeting or conference then head home for a DVD movie night with the family.

Widescreen projectors for home and business come in both WVGA and WXGA. Choosing a lower-cost WVGA (854 x 480) projector will save you some money and cover all the bases if you will be watching only DVD movies. For displaying HDTV content, a WXGA (1280 x 800) projector is required. This pixel array will enable you to display any and all HDTV content up to 720p with no rescaling. You will even be able to view 1080i or 1080p material on the more-capable WXGA projectors, but the projected image will need compression so that the 1920 x 1080 pixels in a 1080i or 1080p HDTV image can be scaled into the native pixel array of the WXGA projector.

Ask the experts

Remember, image resolution is only one of many important factors in assessing your projector. Color balance, brightness (lumens), edge-to-edge clarity and other specifications may be even more important at times. Business projectors are becoming more media-savvy all the time, just as business people are becoming as sophisticated as the audiophile and videophile consumers that have driven the advancements in home theater technology.

New business projectors will be debuting in the coming year from leading manufacturers, models that promise to bedazzle and amaze an audience of engineers or CEOs the way that home theater projectors wow the family with Harry Potter movies. Whether you contact one of our expert Account Executives now or later—by e-mail, phone or rental quote request—you will get state-of-the-art advice and equipment for your meeting, conference or presentation needs.

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