Refers to supplying a constant realtime media service. Although broadcast TV has done this from the beginning, and SDI streams data, the term is more usually associated with delivery by networks, usually the Internet where it accounts for a large majority of the traffic. The transmission comprises a stream of data packets which can be viewed/heard as they arrive though are often buffered, stored slightly in advance of viewing/hearing, to compensate for any short interruptions of delivery. For the Internet, media is compressed and generally offers acceptable results for audio and video. There are three predominant video streaming solutions: RealNetworks with RealVideo, RealAudio and RealPlayer, Microsoft Windows Media and Apple QuickTime; each with their particular advantages. As Internet transfers are not deterministic, pictures and sound may not always be continuously delivered.
Many popular sites, such as YouTube and the BBC iPlayer, offer both SD and HD services. A few are working with 4K UHD. Most TV and radio stations offer live streaming services.