Technology

Let the High-Def Games Begin


Deb De Gregorio wants a better Olympics viewing experience on her seven-year-old TV. She writes: The Olympics on NBC (GE) appears to be broadcast in widescreen. On my older Sony (SNE), the left and right sides are cut off. So that means you can't see the little timer as racers go down hill. And people are cut out of the image on the sides.

I am not going to run out and buy a new TV, because my 7-year-old Sony works just fine, thank you. Is there any sort of converter box gizmo that would allow me to get the broadcast in letter box? I don't love TV so much that I must have HDTV. I am a digital Comcast (CMCSA) subscriber and at those rates, I deserve the whole picture.

Welcome to the digital transition. One of the major issues for both broadcasters and viewers is the fundamental incompatibility between the squarish 4:3 display of conventional TV, where the picture contains 3 inches of height for every 4 inches of width, and the widescreen 16:9 aspect ratio of high-definition TV.

BOXED IN. Short of using a separate set of cameras, and in effect doing two broadcasts, there are three ways to make an image shot for widescreens visible on standard displays. One, generally not used except for movies and some commercials, is to letter-box the image. Black bands are used at the top and bottom of the screen to leave a 16:9 area in the middle. This is the only way to preserve the widescreen image, but broadcasters avoid it because they think viewers feel cheated by leaving a significant piece of the screen unused.

The second is to pan and scan to select the best 4:3 image from the 16:9 screen. This is widely used to convert widescreen movies for TV viewing, but it is very difficult and expensive to implement in real time for sports events or other live broadcasts.

The most widely used technique, and what NBC appears to be doing, is to have camera operators and directors constantly pay attention to a 4:3 standard-definition "safe area" in the middle of the 16:9 view. This cheats everyone a little. Standard-definition viewers don't see the full picture, while high-def viewers don't always get the best possible picture. Their shot has to be set up so that nothing really important is at the edges of the screen. But it's a compromise that works.

LOSING YOUR EDGE. In addition to all that, it sounds like your TV is suffering from a common but annoying problem that afflicts cathode-ray-tube machines and often gets worse as the set gets older. It's called overscan, and it happens when the electron gun scans an area that's bigger than the viewable area of the picture tube. As a result, you lose edges of the image.

When I watched the Olympics on a standard-definition TV, the timers and such showed up at the edges of the picture. But add a little overscan and they would easily have been lost. In any event, don't blame Comcast, at least not for this. They can only distribute what NBC sends them.


Steve Ballmer, Power Forward
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