Glossary of Terms
720p - 720 horizontal lines of vertical resolution that are displayed or stored progressively (see below).
1080i - 1080 horizontal lines of vertical resolution that are displayed or stored in an interlaced method (see below).
1080p - 1080 horizontal lines of vertical resolution that are displayed or stored progressively (see below).
Bit rate - This is the data rate. It is the amount of data (bits) sent per sec. There are 8 bits in 1 byte. Therefore I KiloByte=8Kilobits
Brightness - This is measured in cd/m2.
Coaxial - Aerial lead. This is not the definition of coaxial but rather the main example of what type of coaxial cable is used in the UK.
Component - This is a better analogue picture as instead of sending all the video information down one cable (composite) it is separated into 2 or more component parts. In televisions this can be S-Video, RGB or YPbPr. RGB is often used on the scart connection (a terrible connection but one we have all had to live with for some time now). Each colour (red, green, blue) is sent down separate cables. In YPbPr the luminance is carried on the Y cable with blue on the Pb and red on the Pr. The green is made from mixing the blue, red and luminance.
Composite - This is the lowest quality analagoue picture you can get. This can either be composite scart or RF socket where you plug in a coaxial cable. It is a composite of YUV. where Y is luminance and U & V is the colour components of red and blue, which then run down one cable. This affects the quality of the picture.
Contrast Ratio - This is defined as the ratio between the brightest white to the darkest black that a flatscreen tv is capable of displaying. Unfortunately, manufacturers have different definitions of how to measure the darkest and brightest areas.
Downscaling - This is when the resolution of an image has to be reduced to fit on a lower resolution display. For example it would be impossible to see all 1920 lines of resolution if your display only has 1366 lines.
DVI - Digital Video Interface. As the name suggests, this connection keeps the signal digital.
Full or True HD - This is an arbitary term to refer to a resolution of 1920x1080. We say arbitary as there is no limit to high definition. It's just that at present this resolution is the maximum resolution you get on the consumer market.
HD ready - In the UK, this means that the tv is capable of receiving higher definition resolutions. These include 720p and higher. These two formats incorporate the following resolutions: 1920x1080, 1366x768, 1280x1080, 1280x720, 1024x768. You will still need an HD device that can read and decode the signals such as a Sky HD box.
HDMI - High Definition Multimedia Interface. This type of cable can transmit both video, audio and device controlling abilities. The signal is kept digital and uncompressed. There are different versions now but the latest version to buy is 1.3. This is the best connection available for consumers and keeps the image HD.
Interlaced Scanning - This is when the horizontal lines of resolution (vertical resolution) are displayed or stored alternately. In other words, 1080i means that half of these alternate horizontal lines (540) are displayed or stored sequentially from top left to bottom right and then the other half of alternate lines are displayed or stored and fill the gaps.
MPEG - Motion Picture Experts Group. It is a form of motion compression, where information is compressed from one frame to another. In other words, if you are filming the countryside and nothing is moving in the picture except a bird flying, then the same non-moving image data is removed from one frame to the next, thereby reducing the amount of information that needs to be sent per second (bit rate).
PAL - Phase Alternating Line. It is a colour encoding system that the UK and many other countries use. Most of these countries but not quite all (e.g. Brazil) use the tv resolution of 720x576 and 25 frames/second.
Pixel - This is the smallest piece of information of an image that you can get in digital photos and television. Normally, each pixel is made up of 3 component colours - red, green & blue.
Progressive Scanning - This is when the horizontal lines of resolution (vertical resolution) are displayed or stored in succession, as opposed to interlaced.
Resolution - This is the number of pixels in an image. The higher the number, the better the picture quality.
Scart - 'Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs'. As you can probably tell it is an analogue standard set by the French. It can be used to carry a composite signal and a RGB component signal.
SD - Standard Definition. In the UK this is 720x576.
Uprezzing or Upscaling - This is when the resolution of one image is scaled up so as to fit into the native resolution of another device.