Digital television is changing the way we think about our viewing in ways that were never practical and in many cases not possible with analog TV. It will literally become yet another new "window" on the world. Digital TV, with its MPEG-2 compression scheme, offers higher quality picture and sound than analog TV (Gerbarg, 1999). Choices will increase with many more channels. Interactive television helps place control of viewing in the hands of viewers instead of broadcasters. Combined with a phone line, digital TV can give everyone access to the Internet in a way with which they feel at ease, opening up new opportunities for education, access to information, shopping and games. Digital television will have both similar and different standards than analog TV. The combination of Dolby Digital 5.1 surround sound and a widescreen picture will pose competition to the motion picture industry that wasn't possible with analog TV (Casswell, 2000).
In the United States, as opposed to many other countries, a conversion to both digital signals and high-definition pictures is occurring at the same time. Some countries are broadcasting in high-definition pictures but are still using an analog signal. Digital signals, in contrast to analog, are much easier to compress. Compression is required because five times as much information must fit into the same 6MHz bandwidth that analog TV is transmitted in. MPEG-2 compression, the compression method that will be used, can reduce the number of bits transmitted by approximately 55:1 (Collins, 2001). This is made possible because MPEG-2 takes advantage of how the eye perceives color variations and motion. Inside each frame, an MPEG-2 encoder records just enough detail to make it look like nothing is missing. The encoder also compares adjacent frames and only records the sections of the picture that have moved or changed. If only a small section of the picture changes, the MPEG-2 encoder only changes that area and leaves the rest of the picture unchanged.