Direct TV Explains Aspect Ratios of Different Technology

One of the most noticed, but least understood aspects of TV technology is aspect ratio. Aspect ratio defines the shape of a picture that appears on a TV, movie, or HDTV screen as well as the shape of the screen itself.

The aspect ratio is the ratio between the screen's width and its height. For example, no matter how big the actual screen size of a standard definition TV set, it will be four inches wide for every three inches of hight it has and therefore have an aspect ratio of 4:3. For example, if you had a screen that was four inches on its top edge, the side would be three inches long. By the same token, a screen that's forty inches across its top, would have to be thirty inches high.

The other major aspect ratio is 16:9. This aspect ratio is what most of us think of when we hear the term "wide screen," and is the aspect ratio that's found on big movie screens (the normal type, not IMAX) and HDTV sets. The fact sixteen is the square of four and nine is the square of three should not lead one to believe that 16:9 is another way of saying 4:3. The difference can be observed by taking a close look at any HDTV set or any movie that's displayed in wide screen format: the width is almost twice that of the height. In the case of 16:9, a movie theater screen that's sixteen feet across its top edge would be nine feet high. Considering that eight is half of sixteen and that eight is only one less than nine, this aspect ratio does have a much different shape than a 4:3.

Another more obscure aspect ratio is even wider than 16:9. This is used on some films- most notably Star Wars. All you have to do in order to see the difference between this aspect ratio and 16:9 is to walk by an HDTV in an electronics store that's displaying one of the Star Wars movies. You'll notice that there is blank screen both above and below the actual image. Occasionally, the blank space at the bottom of the screen- the part that would make up the difference between normal 16:9 and this special aspect ratio- is used to display subtitles when someone is speaking an alien language, but considering how seldom the space is used for that, there must be a different rationale for making that aspect ratio the way it is. Perhaps the extra width was chosen in order to accentuate the grandeur of the story.

Unfortunately aspect ratio is a source of confusion for many people. While it is true that HDTV is never displayed in 4:3 aspect ratio, not everything that's displayed in 16:9 is considered HDTV. In fact, many TV shows are being produced in standard definition and with an aspect ratio of 16:9. This has led a lot of people to assume that a lot of TV programming is in HDTV format, when in fact it's not. This is especially true when an an HDTV channel shows standard def programming shot in 16:9.

While aspect ratios may be confusing, they are certainly an aspect of TV technology that can add enjoyment to TV viewing.