Last Updated: Fri, 12 Aug 2011 > Related Articles
This article addresses FAQs about HDTV including: picture quality, picture display, and common terms.
HDTV (high definition TV) is a TV display technology that provides a higher picture and sound quality than standard TV sets.
Roughly half of prime time TV programs of the major networks are available in the HDTV format (16:9). The other half are available in the standard-definition format (4:3). The aspect ratio of the content is controlled by the content providers; example: HBO and Showtime. You can access the providers website to see which programming is released in the HDTV format (16:9).
- When a standard-definition (4:3 aspect ratio) program is viewed on a HDTV (16:9 aspect ratio), the HDTV centers the image on the screen with black or gray bars on either side.
- When HDTV (16:9 aspect ratio) content is displayed on a standard-definition TV (4:3 aspect ratio), black bars will appear at the top and bottom of the screen.
Refer to your TV user guide for directions on removing the bars. If you have a Scientific Atlanta cable box, use the stretch and zoom HD settings to fill the TV screen area with the image.
- A TV is considered to have burn-in when the HDTV colors are not evenly displayed across the screen.
- To avoid burn-in, use the stretch and zoom HD settings to fill the TV screen area with the image. In some cases you can substitute gray bars for black bars to minimize burn in. You can also try turning your contrast down to 50 percent or lower.
- Burn in is usually not covered under warranty, and ONLY affects the following TV displays:
- Direct-view CRT
- Plasma flat-panel
- CRT-based rear projection
The 4:3 aspect ratio is the shape of the standard TV monitor (square).
The 16:9 aspect ratio is the shape of most HDTV monitors (rectangular). HDTVs have been manufactured in both 4:3 and 16:9 aspect ratios.
Widescreen is a term used for the 16:9 aspect ratio which is larger than the standard definition TV screen.
- 1080p is the shorthand identification for a category of HDTV video modes. The number 1080 represents 1,080 lines of vertical resolution (1,080 horizontal scan lines), while the letter p stands for progressive scan (meaning the image is not interlaced). The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels.
- 1080i is a (HDTV) video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels and a frame resolution of 1920×1080 or about 2.07 million pixels.
- 720p is the shorthand name for a category of HDTV video modes. The number 720 stands for the 720 horizontal scan lines of display resolution (also known as 720 pixels of vertical resolution), while the letter p stands for progressive scan or non-interlaced.
- 720 or 1080 lines of resolution from both the channel broadcast and the HDTV monitor (Note: A 480i DVD is not high definition, even though the image quality is considerably higher than a standard definition TV broadcast on a standard defintion TV.)
- Ability to display 16x9 aspect ratio pictures
- Y Pb Pr video component connections from the cable receiver to the HDTV
- Audio in the Dolby Digital (AC-3) format to support "5.1" surround sound
Most HDTV monitors can display an SDTV (480i) signal. If "sidebars" appear, you can press the SETTINGS button on the remote control twice to access the HDTV settings. Then select the 480i Stretch setting, which will stretch the 4:3 program to fill the entire screen area.
Cox HD service refers to a type of digital cable that is at a higher resolution than Cox Digital Cable. In order to receive Cox HD service, a HDTV-capable or HDTV-ready TV and a Cox HD receiver are required.
Analog (NTSC) refers to the signal used to transmit most TV signals today. Digital TV signals (DTV) are representations of analog TV signals that are made up of bits — ones and zeros — much like the bits that are used by your computer and your CD player. Analog TV signals are adversely affected as they travel from the signal transmitter to your TV by such things as radiation from power lines and atmospheric conditions. Therefore, the quality of the picture you see on your standard analog TV is degraded relative to the signal that was transmitted. Although digital signals are also adversely affected by external environmental conditions during transmission, digital receivers have an easier time recovering the transmitted signal. This is because the digital receiver only has to distinguish between a one and a zero. This can be compared with transmission of Morse Code — as long as the person at the receiving end can distinguish between a dot and a dash, no information is lost.
DTV is a general reference to digital TV, as compared to analog TV. DTV broadcasts can be either HDTV (high-definition) or SDTV (standard-definition). HDTV can broadcast at resolutions typically as high as 1920 by 1080 pixels (2 million pixels) whereas the resolutions of SDTV broadcasts are typically only as high as 640 by 480 pixels (290,000 pixels). In comparison, analog TV produces a total of about 210,000 pixels. Broadcasters and cable providers can choose which format of DTV they transmit, amd most DTVs and new HDTV receivers will be able to receive the signal regardless of which format is transmitted. Note however that your standard analog TV will not be able to receive DTV signals (neither HD or SD).
The HD receiver will be much the same as your current digital receiver; however, it will have the ability to provide HD signals to your HDTV.
A sidecar is a box that connects to a Motorola digital receiver which enables the HD signals to the HDTV. The sidecar was available prior to the integrated Motorola 5100 HD receiver. Currently, (May 2003) sidecars exist in the Omaha system only.
The first receiver Cox will deploy automatically converts all high-definition signals to 1080i format, regardless of the broadcast signal format. If your TV only supports 720p (some older HDTVs and some plasma TVs) and you are using a Scientific Atlanta HD receiver, you will not be able to view HD signals in the first release of Cox HD service. However, the next version of SA receivers will support the 720p format.
Note: This is not an issue with the Motorola 5100 HD receivers because they support 720p signal format.
|Scan Lines||Pixels||Classification||Aspect Ratio||Refresh Rate||Quality|
|1080||1920 x 1080||HDTV||16:9||60i, 30p, 24p||Best|
|720||1280 x 720||HDTV||16:9||60p, 30p, 24p||Best|
|480||704 x 480||SDTV||16:9||60p, 60i, 30p, 24p||Better|
|480||704 x 480||SDTV||4:3||60p, 60i, 30p, 24p||Better|
|480||640 x 480||SDTV||4:3||60p, 60i, 30p, 24p||Good|