Precept developed an Internet video product named IP/TV. The term IPTV first appeared in 1995 with the founding of Precept Software by Judith Estrin and Bill Carrico. The combination of DCT and ADSL technologies made it possible to practically implement VOD services at around 2Mbps bandwidth in the 1990s. ADSL increased the bandwidth of a telephone line from around 100kbps to 2Mbps, while DCT compression reduced the required bandwidth of a digital television signal from around 200Mbps down to about 2Mbps. VOD services were only made possible as a result of two major technological developments: discrete cosine transform (DCT) video compression and asymmetric digital subscriber line (ADSL) data transmission. DCT is a lossy compression technique that was first proposed by Nasir Ahmed in 1972, and was later adapted into a motion-compensated DCT algorithm for video coding standards such as the H.26x formats from 1988 onwards and the MPEG formats from 1991 onwards. Motion-compensated DCT video compression significantly reduced the amount of bandwidth required for a television signal, while at the same time ADSL increased the bandwidth of data that could be sent over a copper telephone wire. Up until the early 1990s, it was not thought possible that a television programme could be squeezed into the limited telecommunication bandwidth of a copper telephone cable to provide a video-on-demand (VOD) television service of acceptable quality, as the required bandwidth of a digital television signal was around 200Mbps, which was 2,000 times greater than the bandwidth of a speech signal over a copper telephone wire. 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. These services are delivered across an access agnostic, packet switched network that employs the IP protocol to transport the audio, video and control signals. #Movist lag h.264 tv#These services may include, for example, Live TV, Video On Demand (VOD) and Interactive TV (iTV). IPTV is defined as the secure and reliable delivery to subscribers of entertainment video and related services. One official definition approved by the International Telecommunication Union focus group on IPTV (ITU-T FG IPTV) is: Historically, many different definitions of IPTV have appeared, including elementary streams over IP networks, MPEG transport streams over IP networks and a number of proprietary systems. IPTV services may be classified into live television and live media, with or without related interactivity time shifting of media, e.g., catch-up TV (replays a TV show that was broadcast hours or days ago), start-over TV (replays the current TV show from its beginning) and video on demand (VOD) which involves browsing and viewing items of a media catalogue. IPTV in the telecommunications arena is notable for its ongoing standardization process (e.g., European Telecommunications Standards Institute). IPTV is also used for media delivery around corporate and private networks. IPTV is widely deployed in subscriber-based telecommunications networks with high-speed access channels into end-user premises via set-top boxes or other customer-premises equipment. This is known as streaming media.Īlthough IPTV uses the Internet protocol it is not limited to television streamed from the Internet ( Internet television). As a result, a client media player can begin playing the content (such as a TV channel) almost immediately. Unlike downloaded media, IPTV offers the ability to stream the source media continuously. This is in contrast to delivery through traditional terrestrial, satellite, and cable television formats. Internet Protocol television ( IPTV) is the delivery of television content over Internet Protocol (IP) networks.
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