IPTV services may be classified into three main groups: live television, time-shifted programming, and video on demand(VOD). It is distinguished from general Internet-based or web-based multimedia services by its on-going standardization process (e.g., European Telecommunications Standards Institute) and preferential deployment scenarios in subscriber-based telecommunications networks with high-speed access channels into end-user premises via set-top boxes or other customer-premises equipment.
Historically, many different definitions of IPTV have appeared, including elementary streams over IP networks, transport streams over IP networks and a number of proprietary systems.
The official definition approved by the International Telecommunication Union focus group on IPTV (ITU-T FG IPTV) is as follows:
"IPTV is defined as multimedia services such as television/video/audio/text/graphics/data delivered over IP based networks managed to provide the required level of quality of service and experience, security, interactivity and reliability."
Another official and more detailed definition of IPTV is the one given by Alliance for Telecommunications Industry Solutions (ATIS) IPTV Exploratory Group on 2005:
"IPTV is defined as the secure and reliable delivery to subscribers of entertainment video and related services. These services may include, for example, Live TV, Video On Demand (VOD) and Interactive TV (iTV). These services are delivered across an access agnostic, packet switched network that employs the IP protocol to transport the audio, video and control signals. In contrast to video over the public Internet, with IPTV deployments, network security and performance are tightly managed to ensure a superior entertainment experience, resulting in a compelling business environment for content providers, advertisers and customers alike."
One definition for consumer IPTV is for single or multiple program transport streams (MPTS) which are sourced by the same network operator that owns or directly controls the "last mile" to the consumer's premises. This control over delivery enables a guaranteed quality of service (QoS), and also allows the service provider to offer an enhanced user experience such as better program guide, interactive services etc.
In commercial environments IPTV is widely deployed for distribution of live TV, video playout channels and Video on Demand (VOD) material across LAN or WAN IP network infrastructures, with a controlled QoS.
In 1994, ABC's World News Now was the first television show to be broadcast over the Internet, using the CU-SeeMevideoconferencing software.
The term IPTV first appeared in 1995 with the founding of Precept Software by Judith Estrin and Bill Carrico. Precept designed and built an Internet video product named IP/TV. IP/TV was an MBONE compatible Windows and Unix-based application that moved single and multi-source audio/video traffic, ranging from low to DVD quality, using both unicast and IP multicast Real-time Transport Protocol (RTP) and Real time control protocol (RTCP). The software was written primarily by Steve Casner, Karl Auerbach, and Cha Chee Kuan. Precept was acquired by Cisco Systems in 1998. Cisco retains the IP/TV trademark.
Internet radio company AudioNet started the first continuous live webcasts with content from WFAA-TV in January, 1998 and KCTU-LP on January 10, 1998.
Kingston Communications, a regional telecommunications operator in UK, launched KIT (Kingston Interactive...