Video-on-Demand

Video on demand (display) (VOD) are systems which allow users to select and watch/listen to video or audio content such as movies and TV shows when they choose to, rather than having to watch at a specific broadcast time, which was the prevalent approach with over-the-air broadcasting during much of the 20th century. IPTV technology is often used to bring video on demand to televisions and personal computers.

Television VOD systems can either "stream" content through a set-top box, a computer or other device, allowing viewing in real time, or download it to a device such as a computer, digital video recorder (also called a personal video recorder) or portable media player for viewing at any time. The majority of cable- and telephone company-based television providers offer both VOD streaming, including pay-per-view and free content, whereby a user buys or selects a movie or television program and it begins to play on the television set almost instantaneously, or downloading to a digital video recorder (DVR) rented or purchased from the provider, or downloaded onto a PC or to a portable device, for viewing in the future. Internet television, using the Internet, is an increasingly popular form of video on demand. VOD can also be accessed via desktop client applications such as the Apple iTunes online content store.

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