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The Truth Behind 4:3 and 16:9 Formatting

Contents

How do you get a 16:9 image format from 4:3 panels and chips?

Glad you asked. There is only one way to do it. And that is to mask off a horizontal portion of the 4:3 panel or chip at the top and/or bottom in order to create the 16:9 aspect ratio. By masking off a portion of the 4:3 display, you reduce the number of pixels that will be used to create the image. That means fewer lines of resolution. Furthermore, the masking also blocks a portion of the light that the projector is capable of delivering, so less light will reach the screen.

This has some important consequences. First, on a projector that operates like this, if you have a DVD that has both Pan-and-Scan (4:3) and Widescreen (16:9) format, you will always get better resolution and more light onto the screen with the Pan-and-Scan version. That's because Pan-and Scan uses the full 4:3 capability of the panels or chips. I know that will give some home theater buffs the willies, but it's the way it is.

Second, if you have a projector with a 4:3 physical display, you should use a screen that is also 4:3 in order to get the maximum performance from your projector when viewing 4:3 material. The best way to view 16:9 in this situation is to live with the black bars at top and bottom. If you want, you can get screens that will automatically raise/lower masking material that adjusts the viewable screen to 16:9 so that the black bars fall onto black masks and become invisible. The screen masking is then retracted when you switch to 4:3 sources. With this kind of set up, you can take maximum advantage of the native 4:3 display format in the projector.

Caution consumers! Be careful what you ask for; you might get it

Unfortunately, there is a strong perception among consumers that a 4:3 image should be smaller than 16:9. Not true. These are simply two different shapes of rectangles. Neither one is inherently "bigger" or "wider" than the other as either one can be projected at any size. Nevertheless, what many consumers want is this: they want a 4:3 image format in which to watch standard 4:3 source material. Then when switching to 16:9 they want the viewable image to widen noticeably. They have an emotional need to have "widescreen" look wider than 4:3. They are most happy to install a 16:9 screen, show a 4:3 image in the middle of it with black bars on both sides, then have the screen burst into full glory with breathtaking widescreen panorama when the source changes to 16:9.

You want it? You got it! Some manufacturers (not all do this) have devised a way to produce this phenomenon using physical 4:3 displays. And you probably won't like how it's done.

Actually, it's easy. The standard resolution of 4:3 video fits easily inside the resolution of todays data projectors. By limiting the resizing of the video, the projector is made to show a smaller 4:3 image than it is technically capable of. That image will have a black frame around it. When you switch to 16:9, the projector removes all or most of the vertical sides of the black frame, and just like magic you've got what looks like a bigger widescreen display. But the effect is produced by making the 4:3 image artificially small to begin with.

Cool right? Not necessarily. Consumers may pay dearly but unknowingly for this illusion. By masking off all four sides of a 4:3 display to create a smaller 4:3 image, part of the light is blocked. So you get a much dimmer 4:3 image than you would otherwise have. Furthermore, you have many fewer pixels to make the image so both horizontal and vertical resolution gets hammered. And the pixel structure itself becomes more visible for any screen size as you use your zoom lens to fill your screen with the reduced resolution image. None of this is good news.

We don't want to pick on any vendor in particular since a number of them do this. But take for example the Davis Cinema One. This machine has a physical DMD chip resolution of 800 x 600. With data sources, the image is shown in full 800 x 600 which is just fine. But switch to a video source in 4:3 and what you do get? A black frame mask is thrown around the edge of the chip and the actual video image is produced using a reduced active pixel matrix of 690 x 532.

The result: instead of 480,000 pixels on the screen (800 x 600), you get a mere 367,080 (690 x 532). So you lose 112,920 pixels, or 23.5% of the display's resolution, and 23.5% of the projector's light output. To top it off, the pixel matrix itself is a little more visible than it needs to be if you zoom the image to make up for the lost size. And the ONLY benefit to this sacrifice in 4:3 performance is the emotionally satisfying experience of seeing your 16:9 material open up and look a little wider than your 4:3.

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Contents: Defining Aspect Ratio Truth in Formatting Consumer Demand