Enter the New Frontier of Television

High Definition signals reach La Cañada Flintridge by one of three routes.

There are antennas that broadcast our local stations' digital signals, some of which contain HD programs.

There are HD channels that arrive here through Charter Communications' Cable system, and HD can be acquired through satellite providers (Dish and DirectTV).

HD looks and sounds great because it has up to four times the picture information of regular TV. The audio is usually a six-channel, high quality configuration called Dolby 5.1. It contains five separate channels and a subwoofer channel.

A regular television tube is almost square, but HD is a wide screen format. You can view HD signals on a regular TV, but the image is not as clear and the picture has to be letterboxed (with the black bars at the top and bottom of the picture), or the image can fill the screen cutting the sides of the original HD picture.

Some HD sets are capable of receiving HD from television stations. Others need an additional piece of equipment called a tuner. Cable companies provide a decoder so that you can see their HD broadcasts. Satellite providers have a special HD dish and decoder that gets the signal to your TV.

Is it worth it?

It all depends on your personal viewing choices.

Over the Air broadcasting, of digital signals does not always mean the picture is High Definition. It is not uncommon to see regular sized programming coming from a digital broadcast; however, much of the networks' morning and prime time broadcasts are in HD. That's hours of HD daily. Many sporting events are also broadcast in HD.

There are two sizes to the HD signal, defined by its horizontal line scan rate of either 720 and 1,080. Each of these signals has additional options as to how many frames per second are projected. This is of no real concern because the HD tuner or converter box recognizes the different types of HD signals. Currently KABC Channel 7 broadcasts in 720, and KCBS Channel 2 and KNBC Channel 4 use 1,080. Though there are fewer lines in the KABC broadcast, the picture is projected as an entire frame, called progressive scanning.

Many people believe the progressive scan looks crisper than the interlace process, so the 720 progressive lines are approximately equal in clarity to the 1.080 interlaced format. Most cable and satellite signals use 1,080.

What does all this mean? Well, eventually your current television will stop receiving local broadcasts entirely because the Federal Communications Commission is going to take back the original broadcast frequencies and leave only the new digital channels. When that happens, you will have to buy a converter or a new television. This won't happen for a few years.

In the meantime, La Cañada Flintridge is HD ready. The question is, are you?

Steve Brown of La Cañada Flintridge is author of "Video Editing: Intro to Non-linear Editing."

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