HDTV FAQ
By CNET staffJun 12, 2007
The basics
What is HDTV?
HDTV stands for high-definition television, and it marks the biggest leap forward for television since color TV made its debut in the 1950s. HDTV images are more than twice as detailed as standard analog TV, delivering rich, realistic images, as well as multichannel, movie theater-quality surround sound. HDTVs can display both regular and HDTV images, but they need HD sources to look their best.
Just how much sharper is HDTV than regular TV?
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What's the difference between 720p and 1080i HD broadcasts?
The short answer is that they both look great, and most people will have a hard time telling the difference. Here's the medium-size answer: The numbers 720 and 1080 refer to horizontal pixel counts, while the letters p and i refer to the picture-scanning method--either progressive or interlaced. Proponents of 1080i HD will tell you that they offer the most lines of resolution, which is true. However, 1080i images are interlaced, meaning that a tube TV draws the picture in two passes: Once for the odd-numbered lines, and again for the even-numbered lines. For 720p, or progressive, broadcasts, tube TVs draw each frame in a single pass, making for a smoother picture (non-tube variants such as LCD TVs display everything as progressive scan). While most viewers probably won't be able to tell the difference, videophiles tend to prefer the smoother images of 720p. Even higher-bandwidth 1080p broadcasts could offer the best of both worlds, but they're not going to be available anytime soon.
How is the sound quality on HD shows?
At best, standard-definition shows have 4-channel Dolby surround sound (left, center, right, and one rear "surround" channel), but they usually have 2-channel stereo. High-definition broadcasts, on the other hand, support 5.1-channel Dolby Digital surround sound (left, center, right, left and right surround, and a subwoofer--the .1 part, for booming bass). This is similar to the sound you hear in a movie theater or, with the properly equipped home theater, on a DVD. Not all HD broadcasts have 5.1 Dolby Digital yet, but the majority does, and you'll hear--and feel--the difference. Of course, you'll need a home theater system to take full advantage of it.
Can I record HDTV shows and movies?
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Do I need a new TV to watch high-definition TV shows?
Yes. You'll need both a TV that's capable of displaying enhanced-definition (EDTV) or high-definition (HDTV) images as well as an HDTV tuner (cable, satellite, or over the air) to receive the HD signals. Until recently, most HDTV sets came without their own digital tuners; if you see a set with the label HD-ready, it won't display HD images without a separate HD set-top box. However, HDTV set such as the Samsung IDTV now come with built-in digital tuners for over-the-air HD broadcasts.
