Video on demand is a programming system which allows users to select and watch/listen to video or audio content such as movies and TV shows whenever they choose, rather than at a scheduled broadcast time, the method that prevailed with over-the-air programming during the 20th century. IPTV technology is commonly used to bring VOD to televisions and personal computers.
Television VOD systems can stream content through either 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:
- VOD streaming, whereby a user selects a video program and it begins to play immediately on the television set, or
- downloading to a digital video recorder (DVR) rented or purchased from the provider, or downloading onto a PC or to a portable device, for viewing in the future.
Some airlines offer VOD as in-flight entertainment to passengers through individually controlled video screens embedded in seatback or armrests or offered via portable media players. Some video on demand services, such as Netflix, use a subscription model that requires users to pay a monthly fee to access a bundled set of content, which is mainly movies and TV shows. Other services use an advertising-based model, where access is free.