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High Definition television, or HDTV, gives viewers crystal-clear pictures integrated with Dolby® Digital 5.1 channel surround sound - the entertainment experience that has been imagined but was never possible on standard analog televisions. HDTV reproduces theater-quality sights and sound by digitizing TV programming, allowing it to be transmitted and received the same way that a DVD player can reproduce movies with big-screen quality effects.
What is HDTV?
HDTV provides high resolution widescreen High Definition programming, integrated with Dolby® Digital 5.1 channel surround sound that makes your television viewing experience come to life. Live life in high definition.
All-digital HD broadcasts transmit as many as 10 times more pixels, or picture frames, than you are used to seeing on a standard broadcast television, resulting in sharper, more lifelike colors and richer sounds.
HD programs are broadcast in widescreen (16:9) format. Unlike standard (4:3) format, which causes some images to appear squeezed in the middle or cut off along the sides of the screen, widescreen HD broadcasts reproduce screen images as they were originally meant to be seen.
HDTVs use a method of scanning called "progressive" scan to produce a flicker-free image, making text easier to read and fast-motion video appear smoother than televisions that use interlaced scanning. Interlaced scanning refreshes pixels in alternations - first the odd lines, then the even lines - showing only 1/2 of the screens picture elements at any given moment. Progressive scan means that all 1 million pixels on the screen are refreshed simultaneously.
Glossary of HDTV Terms
Aspect Ratio
Aspect ratio is the difference between the width and height of the picture as it is displayed on the television screen. 4:3, (standard), format causes some images to appear squeezed in the middle or cut off along the sides of the screen. High Definition programs are broadcast in 16:9, (widescreen format), which allows the images to be projected as they were originally meant to be seen.
Resolution
Resolution is the number of pixels that are displayed on a monitor or screen. The sharpness of the image on a display depends on the resolution and the size of the monitor - the greater the resolution (more pixels) the better the picture!
720p
720 progressive is the entry level for HDTV resolution levels. (1280 x 720 with 921,600 pixels).
1080i
1080 interlaced is an entry level HDTV resolution. Unlike 720p or 1080p, 1080i HDTV's refresh every other line of resolution at a time, so only half the image is displayed at any one time. (1920 x 1080 with 1,036,600 pixels).
1080p
1080 progressive is Full HD. I080p is the highest level of resolution avaliable in the HDTV world. Currently the devices capablie of producing this level of resolution are limited to HDDVD players, Blu-ray players, and the Playstation 3. (1920 x 1080 with 2,073,600 pixels).
Pixels
Pixels, or picture elements, are the individual points of color that make up a television screen image. All digital HD broadcasts transmit as many as 10 times more pixels than you are used to seeing on a standard broadcast TV resulting in sharper, more lifelike colors and richer sounds. HDTV represents the richest pixel format available, with more than 1-2 million active pixels displayed on the television screen at any one time.
Contrast Ratio
Contrast Ratio is a way of expressing the purity of colors in a projected image. This is expressed as XXXX:1, (1000:1, 5000:1, 10,000:1). The higher the contrast ratio, the deeper and richer the coloring. This is especially evident when watching dark scenes. The lower the contrast ratio, the more difficult it is to make out the detail.
Scanning (Interlaced and Progressive)
HDTVs use a method of scanning called "progressive" scan to produce a flicker-free image, making text easier to read and fast-motion video appear smoother. Progressive scan means that all 1 million pixals on the screen are refreshed simultaneously, unlike analog TVs with "interlaced" scan. Interlaced scanning refreshes pixals in alternations - first odd lines, then the even lines. As a result, only half the pixals on screen are showing at any given moment.
8VSB
The signal modulation system used for over-the-air digital television broadcasts.
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