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Go Back To Comcast HDBecome fluent in HD
We rounded up all the words that HD-savvy consumers need to know. Click on a word below to jump down to its definition.
- 1080p, 1080i and 720p
- 16:9
- 4:3
- Analog TV
- Aspect Ratio
- Component Input
- Contrast Ratio
- Digital TV
- Dolby Digital
- Flat-Panel TV
- HDMI
- HDTV
- Horizontal Resolution
- Interlaced
- LCD TV
- Pixel
- Plasma
- Progressive
- Project Infinity
- Resolutions
1080p, 1080i and 720p: 1080p, 1080i and 720p refer to the resolution of HD images. The “p” stands for progressive, meaning progressive scan, and the “i” stands for interlaced. Both progressive and interlaced refer to how an HDTV translates the HD signal into the picture on the screen. The numbers refer to the number of lines of pixels there are: 1080 is a greater number of lines, and therefore a finer resolution than 720.
16:9: This ratio represents the standard HDTV screen size or aspect ratio. Standard TV has an aspect ratio of 4:3 (think movie screen vs. square box).
4:3: Standard “square” TV screen-size
Analog TV: The traditional method of transmitting television signals. Susceptible to interference and “snow” that make a picture less clear.
Aspect Ratio: A television’s width to height ratio. The HDTV standard aspect ratio is 16:9 while standard television is 4:3.
Component Input: Video input with three different signals: The first is the luminance signal (represented as Y) that transmits black and white information in a signal. The second is the PB which transmits the blue part of the signal and the third is the PR which transmits the red part of the signal.
Contrast Ratio: Difference between the white and black portions of the screen. The better the contrast ratio, the better detail will show up in dark pictures. For example, a computer monitor typically displays a contrast ratio of 400:1, while some HDTV screens can go as high as 3000:1.
Digital TV: An innovative type of broadcasting technology that enables a dramatically clearer picture and better sound quality.
Dolby Digital: Six-channel digital audio standard consisting of front left, front right, front center, surround or rear left, surround or rear right plus a separate sub-woofer.
Flat-Panel TV: Display technology that uses plasma or LCD technology and is knows for its thin design - often just a few inches thick.
HDMI: High-definition multimedia interface is a USB-like digital video connectivity standard that transmits both uncompressed digital audio and video signals. HDMI will enable true high-definition audio/video content for consumers.
HDTV: High-definition television.
Horizontal Resolution: Number of vertical lines (or pixels) that can be resolved from one side of an image to the other.
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Interlaced: HDTV scanning method that uses two separate passes to make an image on the TV. The first pass displays the odd horizontal lines and the next pass displays the even lines.
LCD TV: A television that employs a liquid-crystal display screen rather than a CRT. Generally used in small TVs, portable video equipment, front-projectors and larger flat-panel displays. This technology features a lamp that shines light through liquid-crystal panels, then through mirrors and lenses to the screen.
Pixel: Abbreviated from “picture elements,” pixels are dots of red, green and blue that combine to create an image.
Plasma: Display technology that features thousands of tiny tubes filled by ionized gas in a plasma state that glow in different colors and intensities to create an image. Used in large-screen flat-panel TVs.
Progressive: A form of scanning in which each horizontal line is displayed right after the previous one from top to bottom so the image is displayed in one pass instead of two as it is done with interlaced scanning.
Project Infinity: Comcast’s vision to give consumers the ability to watch any movie, television show, user-generated content or other video that a producer wants to make available On Demand.
Resolutions: The image on your TV is made up of small elements called “pixels,” three closely spaced dots of color - red, green and blue. Unlike your traditional TV pixels, HDTV pixels are smaller and spaced closer together, so you get at least 10 times more visual detail, creating a crystal clear image. Pixels are arranged in a horizontal line. The more lines per frame, the better the image. Regular TV has 480 lines per image. HDTV delivers 720 or 1080 active, viewable lines of resolution. To create that true-to-life image HDTV is famous for, those lines are redrawn on the TV screen in a process called “scanning”.
