Although Internet-TV functionality as a Web service has been implemented in various TVs by several manufacturers — often under the moniker of “Smart TV” — there has not been a unified protocol for handling the TV-receiver integration of Internet-provided content and broadcast content, nor has there been a way to provide uniform features across TV manufacturers. But various initiatives are starting to define a common set of protocols that broadcasters and consumer electronics manufacturers can use to provide consistent user experiences across devices, programs and channels. These include IPTV, NRT, DASH, HbbTV and that of the Smart TV Alliance.
Internet TV is a catch-all phrase that typically describes a service that provides content — audio/video, apps, media streaming, Web browsing and games — to PCs and television sets, either by means of built-in functionality, or through a set-top box or game console connected to a TV. Internet TV can take the form of a dedicated service, like Internet Protocol TV (IPTV), which provides constant multichannel video programming distribution to users over a permanent connection, or a shared Web service, such as over an Internet connection provided by an ISP.
IP formats live video into a packetized delivery medium. When streaming video to an Internet terminal (i.e., sending a continuous “live” feed, meant to be presented in real time to a display) IP is used, which provides a method for encapsulating data into packets called datagrams and sending them to a unique terminal over a shared network. Because IP is a connectionless protocol (i.e., the transmitter does not wait for the receiver to be available), some packets may be lost in the transmission. This requires a mechanism to ensure reliability and circumvent lost or out-of-sequence packets. For this reason, IPTV that provides VOD services uses Real-time Transport Protocol (RTP), which provides jitter compensation and detection of out-of-sequence datagrams, and Real-time Streaming Protocol (RTSP), which uses DVR-like commands (e.g., play, pause, etc.) to control the stream.