VOD stands for Video on Demand, which is a technology that allows for the immediate delivery of video content, such as films and TV series, to individual subscribers. It is a distribution platform that delivers content through subscriptions, pay-per-view, and rentals. VOD streaming allows individual viewers to watch a video from a content library for immediate viewing which can be accessed on their TV, personal computer, mobile phone, or any other device. VOD services were made possible as a result of two major technological developments: MPEG video compression and asymmetric digital subscriber line (ADSL) data transmission. VOD systems may use a download-based model, in which the program is stored on a hard disk in the set-top box, or they may transmit over the Internet to a personal computer. Cable and telephone company-based television providers offer VOD streaming, whereby a user selects a video program that begins to play immediately, or downloading to a DVR rented or purchased from the provider, or to a PC or to a portable device for deferred viewing. VOD streaming offers convenience and flexibility as users have the freedom to watch videos whenever they want.