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Standard Definition Television

By definition, a standard definition television or monitor is a display device that has a resolution of 480 lines and a 4:3 aspect ratio (1.33 times wider than tall). If the television has a fixed resolution, like a flat panel LCD for example, it might be represented as 640 x 480 pixels.

Building on this, a common question people tend to ask is, "what does a standard television/monitor do with higher resolution images or widescreen images from DVD's?" We will simplify this answer by frequently referring to the images you'll see below.

Today, the most common issue people with standard definition displays face is the widescreen — or anamorphic — DVD; and in the future similar issues will remain when our television standards change to HDTV. When HDTV becomes required, set top boxes enabling standard definition televisions to display HDTV signals will become absolutely necessary.

The all encompassing problem is: how do we shrink a larger and wider rectangle into to a smaller narrower rectangle?

Interestingly enough, this problem has nothing to do with resolution on the wider image. The flower image above could be any resolution; it is actually the width that is cause for concern. A 16:9 image of any resolution will have the exact same resolution once it is reduced to fit onto a 4:3 aspect ratio standard definition television.

Doing the math for you, a 16:9 image that is placed onto a standard definition 4:3 television will only have a vertical resolution of 360 lines.

360 lines of resolution is a serious drop in overall resolution. This drop in resolution equates to a significant loss of detail when watching a DVD, and a tremendous drop in resolution if you are converting HDTV to fit your older television. This is why investing in a wide screen television, even if it isn't true high definition, is a good idea.

The 16:9 example only covers part of the problem. The vast majority of movies are filmed in an even wider aspect ratio than 16:9.

1.85:1 and 2.35:1 aspect ratios are quite common. When these widescreen images are converted to your standard definition television, you have an even larger loss of resolution, down to 346 and 272 lines, respectively.

You can combat this by limiting your DVD viewing to "pan and scan" DVDs, however you won't see what the director actually intended for you to see. We will cover this in greater detail in the DVD section.

High Definition Television

High definition monitors and televisions are already in a widescreen format, so they don't encounter many issues in displaying widescreen images, although when showing movies that are converted to HDTV with aspect ratios wider 1.85:1 and 2.35:1, you will still experience some loss in resolution and black bars at the top and bottom of an image, as shown below.

So far, the biggest problem for HDTV is lack of true high definition content. Most broadcast stations are merely converting their standard definition signals to HDTV. This means that even though you are watching an HDTV signal, you are still only getting a 4:3 image, unless you "ask" your television/monitor to horizontally stretch the image to fill in the left over space. Most people don't like using the stretch features as it distorts the image, causing objects to appear much wider than they should, as seen below.

Loss of resolution isn't an issue with up-converting any standard definition signal. And, so minute is the amount of resolution lost when viewing wider screen images from film, that true loss of detail is insignificant.

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