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Internet Protocol television

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This article is about internet protocol television. For public television broadcasting in Iowa, see Iowa Public Television.

IPTV (Internet Protocol Television) is a system where a digital television service is delivered by using Internet Protocol over a network infrastructure, which may include delivery by a broadband connection. A general definition of IPTV is television content that, instead of being delivered through traditional broadcast and cable formats, is received by the viewer through the technologies used for computer networks.

For residential users, IPTV is often provided in conjunction with Video on Demand and may be bundled with Internet services such as Web access and VoIP. The commercial bundling of IPTV, VoIP and Internet access is referred to as "Triple Play" service (adding mobility is called "Quadruple Play"). IPTV is typically supplied by a service provider using a closed network infrastructure. This closed network approach is in competition with the delivery of TV content over the public Internet, called Internet Television. In businesses, IPTV may be used to deliver television content over corporate LANs.

History

In 1994, ABC's World News Now was the first television show to be broadcast over the Internet, using the CU-SeeMe videoconferencing 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 RTP/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.[1]

Kingston Communications, a regional telecommunications operator in UK, launched KIT (Kingston Interactive Television), an IPTV over DSL broadband interactive TV service in September 1999 after conducting various TV and VoD trials. The operator added additional VoD service in October 2001 with Yes TV, a provider VoD content. Kingston was one of the first companies in the world to introduce IPTV and IP VOD over ADSL.

In the past, this technology has been restricted by low broadband penetration. In the coming years, however, residential IPTV is expected to grow at a brisk pace as broadband was available to more than 200 million households worldwide in the year 2005, projected to grow to 400 million by the year 2010. Many of the world's major telecommunications providers are exploring IPTV as a new revenue opportunity from their existing markets and as a defensive measure against encroachment from more conventional Cable Television services. In the mean time, there are thousands of IPTV installations within schools, corporations, and other institutions that do not require the use of wide area connectivity.

It is important to note that historically there have been many different definitions of "IPTV" including elementary streams over IP networks, transport streams over IP networks and a number of proprietary systems. Although (in Mid 2007) it is premature to say that there is a full consensus of exactly what IPTV should mean, there is no doubt that the most widely used definition today is for single or multiple program transport streams which are sourced by the same network operator that owns or directly controls the "Final Mile" to the consumer's premises. This control over delivery enables a guaranteed quality of service, and also allows the service provider to offer an enhanced user experience such as better program guide, interactive services etc.

By contrast "Internet TV" generally refers to transport streams sent over IP networks (normally the Internet) from outside the network that connects to the users premises. An Internet TV provider has no control over the final delivery and so broadcasts on a "best effort" basis. Elementary streams over IP networks and proprietary variants as used by websites such as YouTube are now rarely considered to be IPTV services.

Architecture of IPTV

Broadcast IPTV has two major architecture forms: free and fee based. As of June 2006, there are over 1,300 free IPTV channels available. This sector is growing rapidly and major television broadcasters worldwide are transmitting their broadcast signal over the Internet. These free IPTV channels require only an Internet connection and an Internet enabled device such as a personal computer, HDTV connected to a computer or even a 3G cell/mobile phone to watch the IPTV broadcasts. See also: Internet television Mobile TV

In December 2005, independently produced mariposaHD became the first original IPTV broadcast available in an HDTV format. Various Web portals offer access to these free IPTV channels. Some cite the ad-sponsored availability of TV series such as Lost and Desperate Housewives as indicators that IPTV will become more prevalent.

Because IPTV uses standard networking protocols, it promises lower costs for operators and lower prices for users. Using set-top boxes with broadband Internet connections, video can be streamed to households more efficiently than current coaxial cable. ISPs are upgrading their networks to bring higher speeds and to allow multiple High Definition TV channels.

In 2006, AT&T launched its U-Verse IPTV service. Comprised of a national head end and regional video serving offices, AT&T offered over 300 channels in 11 cities with more to be added in 2007 and beyond. While using IP protocols, AT&T has built a private IP network exclusively for video transport.

Local IPTV, as used by businesses for Audio Visual AV distribution on their company networks is typically based on a mixture of: a) Conventional TV reception equipment and IPTV encoders b) IPTV Gateways that take broadcast MPEG channels and IP wrap them to create multicast streams.

IPTV uses a two-way digital broadcast signal sent through a switched telephone or cable network by way of a broadband connection and a set-top box programmed with software (much like a cable or DSS box) that can handle viewer requests to access to many available media sources.

Currently, California based UTStarcom, Inc. and Tennessee based Worley Consulting are two companies offering end-to-end networking infrastructure for IPTV-based services.

Protocols

IPTV covers both live TV (multicasting) as well as stored video (Video on Demand VOD). The playback of IPTV requires either a personal computer or a set-top box connected to a TV. Video content is typically compressed using either a MPEG-2 or a MPEG-4 codec and then sent in an MPEG transport stream delivered via IP Multicast in case of live TV or via IP Unicast in case of Video on Demand. IP Multicast is a method in which information can be sent to multiple computers at the same time. The newly released (MPEG-4) H.264 codec is increasingly used to replace the older MPEG-2 codec.

In standards-based IPTV systems, the primary underlying protocols used for:

Live TV is using IGMP version 2 for connecting to a multicast stream (TV channel) and for changing from one multicast stream to another (TV channel change).

VOD is using the Real Time Streaming Protocol (RTSP).

Currently, the only alternatives to IPTV are traditional TV distribution technologies such as terrestrial, satellite and cable. However, cable can be upgraded to two-way capability and can thus also carry IPTV.

NPVR (network-based Personal Video Recorder)

Network Personal Video Recording is a consumer service where real-time broadcast television is captured in the network on a server allowing the end user to access the recorded programs on the schedule of their choice, rather than being tied to the broadcast schedule. The NPVR system provides time-shifted viewing of broadcast programs, allowing subscribers to record and watch programs at their convenience, without the requirement of a truly personal PVR device. It could be compared as a "PVR that is built into the network" -- however that would be slightly misleading unless the word "Personal" is, of course, changed to "Public" for this context.

Subscribers can choose from the programmes available in the network-based library, when they want, without needing yet another device or remote control. However, many people would still prefer to have their own PVR device, as it would allow them to choose exactly what they want to record. This bypasses the strict copyright and licensing regulations, as well as other limitations, that often prevent the network itself from providing "on demand" access to certain programmes (see Heroes, below).

In the UK, Virgin Media (the cable TV brand which also provides telephone, Internet and cellular services) has such an NPVR service called "Virgin On Demand". It currently provides access to a limited-but-growing volume of documentaries, films, drama series and music videos "on cue"; however it is important to take into account the technological limitations which can result in noticeable delays during playback, and in response to the "pause", "rewind" and "fast forward" features that it shares in common with VCRs and DVD Players. There is a smaller library of selected programmes that is available to all customers of the cable TV service for no additional fee, but it is more limited in variety and is intended as a "Catch Up" archive consisting only of programmes that aired within the last seven days.

In Greece, On Telecoms offers an NPVR service to all subscribers in their basic package with all the programming of all major national Greek TV channels for the last 72 hours. The user has to sign in their contract that they agree that the company will record national programming of the last 72 hours FOR them so that they can come around any legal implications (like the ones mentioned here) as this service would work like a personal PVR.

Advantages

The IP-based platform offers significant advantages, including the ability to integrate television with other IP-based services like high speed Internet access and VoIP.

A switched IP network also allows for the delivery of significantly more content and functionality. In a typical TV or satellite network, using broadcast video technology, all the content constantly flows downstream to each customer, and the customer switches the content at the set-top box. The customer can select from as many choices as the telecomms, cable or satellite company can stuff into the “pipe” flowing into the home. A switched IP network works differently. Content remains in the network, and only the content the customer selects is sent into the customer’s home. That frees up bandwidth, and the customer’s choice is less restricted by the size of the “pipe” into the home. This also implies that the customer's privacy could be compromised to a greater extent than is possible with traditional TV or satellite networks. It may also provide a means to hack into, or at least disrupt (see Denial of Service) the private network.

Interactivity

An IP-based platform also allows significant opportunities to make the TV viewing experience more interactive and personalized. The supplier may, for example, include an interactive program guide that allows viewers to search for content by title or actor’s name, or a picture-in-picture functionality that allows them to “channel surf” without leaving the program they’re watching. Viewers may be able to look up a player’s stats while watching a sports game, or control the camera angle. They also may be able to access photos or music from their PC on their television, use a wireless phone to schedule a recording of their favorite show, or even adjust parental controls so their child can watch a documentary for a school report, while they’re away from home.

Note that this is all possible, to some degree, with existing digital terrestrial, satellite and cable networks in tandem with modern set top boxes.

VoD

VoD stands for Video on Demand. VoD permits a customer to browse an online programme or film catalogue, to watch trailers and to then select a selected recording for playback. The playout of the selected movie starts nearly instantaneously on the customer's TV or PC.

Technically, when the customer selects the movie, a point-to-point unicast connection is set up between the customer's decoder (SetTopBox or PC) and the delivering streaming server. The signalling for the trick play functionality (pause, slow-motion, wind/rewind etc.) is assured by RTSP (Real Time Streaming Protocol).

The most common codecs used for VoD are MPEG-2, MPEG-4 and VC-1.

In an attempt to avoid content piracy, the VoD content is usually encrypted. Whilst encryption of satellite and cable TV broadcasts is an old practice, with IPTV technology it can effectively be thought of as a form of Digital Rights Management. A film that is chosen, for example, may be playable for 24 hours following payment, after which time it becomes unavailable.

IPTV based Converged Services

Another advantage of an IP-based network is the opportunity for integration and convergence. Converged services implies interaction of existing services in a seamless manner to create new value added services. One good example is On-Screen Caller ID, getting Caller ID on your TV and the ability to handle it (send it to voice mail, etc). IP-based services will help to enable efforts to provide consumers anytime-anywhere access to content over their televisions, PCs and cell phones, and to integrate services and content to tie them together. Within businesses and institutions, IPTV eliminates the need to run a parallel infrastructure to deliver live and stored video services.

Limitations

Because IPTV requires real-time data transmission and uses the Internet Protocol, it is sensitive to packet loss and delays if the IPTV connection is not fast enough or picture break-up or loss if the streamed data is unreliable. This latter problem has proved particularly troublesome when attempting to stream IPTV across wireless links. Improvements in wireless technology are now starting to provide equipment to solve the problem.

See also

References

  1. ^ http://wichita.bizjournals.com/wichita/stories/1998/02/16/focus1.html
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