HDTV information resource - HD TV plasma television

Currently, broadcasters are facing the challenge of needing to "squeeze" the finer picture detail and higher quality surround sound in the traditional 6 (Mhz) bandwidth used by analog TV. This is achieved through the use of compression software.

Digital TV broadcasting is possible due to the use of a compression and encoding scheme known as MPEG-2. This encoding scheme allows for the compression of the clear and stunning images of digital TV to "fit" into a reasonable amount of bandwidth. In each image, the MPEG-2 software records just enough of the picture without making it look like something is missing. In subsequent frames, the software only records changes to the image and leaves the rest of the image "as is" from the previous frame. The use of MPEG-2 enables the reduction of the amount of data by about 55 to 1.

Already adopted as industry standard by DVDs and several satellite TV broadcast systems, MPEG-2 is very efficient at discarding image detail that the human eye tends to ignore anyway. The image quality is considered to be quite good, and far better than traditional analog TV.

The use of MPEG-2 technology allows an HDTV receiver to communicate with computer multimedia applications directly. This allows for a show broadcast in HDTV to be recorded on a computer or a CD-ROM to be played on HDTV systems. A digital TV decodes the MPEG-2 signal and displays it just as a computer monitor does, giving it high resolution and stability.

The MPEG-2 technology, however, still takes up a significant amount of bandwidth, and so satellite broadcasters have begun to embrace the newer technology of MPEG-4. MPEG-4 compression technology is able to squeeze twice as much HD video into the same amount of bandwidth as MPEG-2. Others will soon likely follow the satellite broadcaster's leads and slowly begin to embrace the newer MPEG-4 technology, making it the new standard.