Two Minute Guide to High Definition Television

HD TV Sets
TV resolution is measured in the number of lines of dots that go down the screen. Old "regular" TVs have 480 lines of dots going down the screen. High Definition TVs have more - either 720 lines, or 1080 lines. Both are called "HD", so you need to look at the TV's specifications to see just how high the definition is. The more lines, the crisper the image. 1080 is best, but costs most.

There are two types of HD TV: Plasma and LCD. Plasma screens use a separate, tiny, light for every dot on the screen. Plasmas looks very lifelike but are more expensive and are hard to make in screens smaller than 42".

LCDs use a tiny colored shutter for each dot, placed in front of a few large backlights. LCDs are similar to computer monitors, with a bluish tint to their picture from the backlight. LCDs have poorer color contrast than plasmas, which means that dark colors, such as strands of dark-colored hair, are harder to differentiate. To lessen this problem, LCDs dim the backlights on areas of the screen with darker colors, and raise the backlight brightness on areas with bright colors, but this introduces halos around bright objects on dark backgrounds.

HD Video Signals
Cable, satellite, and DVD players provide many different kinds of video signals. Vertical resolution can be either 480, 720, or 1080 lines. The old "standard definition" signal you get from broadcast TV and cable has 480 lines from top to bottom. HD broadcast and cable channels give you either 720 or 1080 lines of vertical resolution - again, both are called HD so you have to do a bit or research to figure out just how good the signal is. HD video coming from a DVD player always has a full 1080 lines of vertical resolution.

With HD cable or satellite TV, some channels are broadcast with 720 lines of resolution, and some are broadcast in what is called "1080i". The i stands for interlaced, and it means that each frame of video contains only odd or even lines going down the screen. In other words, each video frame contains only half the image. Cable TV companies do this because they don't have enough bandwidth to transmit a full 1080 lines of signal, so they either send 720 or they send 1080i, which is basically 1080 but with a 50% slower refresh rate. 1080i works out to be better for images that don't move much, whereas images that do, like sports for example, look better on 720.

To distinguish between 1080 and 1080i, 1080 is always called 1080p. The p stands for progressive, and basically just means you're getting all the lines you'd expect.

HD DVD Players
To play a high definition DVD, you'll need to buy a "Blu-Ray" DVD player. They currently sell for around $300. These players can play regular DVDs as well, but their startup time can be as long as a minute and Sony's top model cannot play audio CDs, so you may not want to let your old equipment go just yet.

Video gamers sometimes prefer to buy a Sony Playstation which, apart from its 1080p gaming capabilities, can also play Blu-ray DVDs. The Playstation has a short 10-second startup time when inserting a Blu-Ray DVD.

HD DVD players play discs recorded in a format called Blu-Ray, which was invented by Sony. There used to be two types of high definition DVD: Blu-Ray and HD-DVD. HD-DVD was created by Toshiba, and was not compatible with Blu-Ray. Both formats offered the same excellent 1080 resolution picture quality. At the start of this year it became clear that Blu-Ray was winning in the marketplace, and Toshiba stopped HD-DVD production. Anyone owning an HD-DVD player will now need to buy a Blu-Ray player, as new movies will only be released in the Blu-Ray format. Because "HD-DVD" can refer both to the type of device as well as to the name of Toshiba's specific format, the terminology can be confusing.

HD Cables
The cables that connect HD components to each other are called HDMI cables. They carry both audio and video in one cable so you'll have less cables to worry about. Top quality HDMI cables are sold on Amazon.com for under $10 a cable. However, they are typically sold for $50 at high street stores, so be careful as there's no need to pay that much. Digital signals (like HDMI cables) include error correction and are not susceptible to interference in the same way as analog signals (like speaker wire). A $5 cable from Amazon can be better made than many $49 high street cables.

Suggestions
The best HD TVs are 1080p plasmas. They currently cost about $1500. However, if you're not going to be buying a high definition DVD player (currently about $300) or Playstation, then you'll not be receiving a 1080p signal, so buying a cheaper 720 TV will not make much difference. Also on the smaller (!) 42" plasmas, it's hard to tell the difference between 720 and 1080 lines of resolution.

Panasonic makes the best plasmas. Pioneer's plasmas are also good. Sony makes good LCDs in their XBR series, and many other companies make good LCDs too. I tested these TVs at a local store and even the best Sony XBR LCD TV did not have a picture as good as the cheaper Panasonic 1080p plasma. In addition, LCD TVs look worse than regular old cathode ray TVs when watching non-HD ("standard definition") TV.

So my recommendation is to get a Panasonic Plasma TV. However, LCDs are usually cheaper than plasma screens, and different people will have different opinions about picture quality and on whether one TV's picture looks better than another.