Digital television

A map depicting digital terrestrial television standards

Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. In the 2000s it was represented as the first major evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) formats with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit numerous digital channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. While digital satellite and cable TV deployments began in the 1990s, using standard definition television resolutions (digital SDTV), over-the-air digital TV began transitioning from analog to digital broadcasting in the late 1990s, primarily using high definition television formats (digital HDTV). Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:

With the advent of the broadband Internet in the late 1990s, facilitated by high-speed cable modems and Digital Subscriber Line (DSL) modems, it became possible to stream entertainment-quality video to broadband Internet subscribers. By the late 2000s, broadband Internet speeds were sufficiently high to enable HD-quality video to consumers, allowing Internet Protocol (IP) video to become more competitive with traditional digital TV services. Many Internet content companies emerged, providing expanding libraries of on-demand content. Typically these Internet TV streaming apps are received directly by "smart" HDTV sets through a program guide and Wi-Fi, or through Wi-Fi enabled streaming boxes or streaming USB sticks connected to the HDTV set. Many of the same streaming apps are available to other IP-capable devices inside and outside the home, such as smartphones, tablets, and laptops.

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