Internet Protocol television
Internet Protocol television (IPTV) is the delivery of television content over Internet Protocol (IP) networks. This is in contrast to delivery through traditional terrestrial, satellite, and cable television formats. Unlike downloaded media, IPTV offers the ability to stream the source media continuously. As a result, a client media player can begin playing the content (such as a TV channel) almost immediately. This is known as streaming media.

Although IPTV uses the Internet protocol it is not limited to television streamed from the Internet (Internet television). 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. IPTV is also used for media delivery around corporate and private networks. IPTV in the telecommunications arena is notable for its ongoing standardisation process (e.g., European Telecommunications Standards Institute).

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.

Definition
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. One official definition approved by the International Telecommunication Union focus group on IPTV (ITU-T FG IPTV) is:

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 definition of IPTV, relating to the telecommunications industry, is the one given by Alliance for Telecommunications Industry Solutions (ATIS) IPTV Exploratory Group in 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.

History
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. 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. 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. The combination of DCT and ADSL technologies made it possible to practically implement VOD services at around 2Mbps bandwidth in the 1990s.

The term IPTV first appeared in 1995 with the founding of Precept Software by Judith Estrin and Bill Carrico. Precept developed an Internet video product named IP/TV. IP/TV was an Mbone compatible Windows and Unix-based application that transmitted single and multi-source audio and 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.

Telecommunications company US West (later Qwest) launched an IPTV service called TeleChoice in Phoenix, Arizona in 1998 using VDSL technology, becoming the first company in the United States to provide digital television over telephone lines. The service was shut down in 2008.

Internet radio company AudioNet started the first continuous live webcasts with content from WFAA-TV in January 1998 and KCTU-LP on 10 January 1998.

Kingston Communications, a regional telecommunications operator in the UK, launched Kingston Interactive Television (KIT), an IPTV over digital subscriber line (DSL) service in September 1999. The operator added additional VoD service in October 2001 with Yes TV, a VoD content provider. Kingston was one of the first companies in the world to introduce IPTV and IP VoD over ADSL as a commercial service. The service became the reference for various changes to UK Government regulations and policy on IPTV. In 2006, the KIT service was discontinued, subscribers having declined from a peak of 10,000 to 4,000.

In 1999, NBTel (now known as Bell Aliant) was the first to commercially deploy Internet protocol television over DSL in Canada using the Alcatel 7350 DSLAM and middleware created by iMagic TV (owned by NBTel's parent company Bruncor). The service was marketed under the brand VibeVision in New Brunswick, and later expanded into Nova Scotia in early 2000 after the formation of Aliant.  iMagic TV was later sold to Alcatel.

In 2002, Sasktel was the second in Canada to commercially deploy IPTV over DSL, using the Lucent Stinger DSL platform.

In 2005, SureWest Communications was the first North American company to offer high-definition television (HDTV) channels over an IPTV service.

In 2005, Bredbandsbolaget launched its IPTV service as the first service provider in Sweden. As of January 2009, they are not the biggest provider any longer; TeliaSonera, who launched their service later, now has more customers.

 By 2010, iiNet and Telstra launched IPTV services in conjunction to internet plans.

In 2008, Pakistan Telecommunication Company Limited (PTCL) launched IPTV under the brand name of PTCL Smart TV in Pakistan. This service is available in 150 major cities of the country offering 140 live channels.

In 2010, CenturyLink – after acquiring Embarq (2009) and Qwest (2010) – entered five U.S. markets with an IPTV service called Prism. This was after successful test marketing in Florida.

In Brazil, since at least 2012,  Vivo has been offering the service Vivo TV Fibra in 200+ cities where it has FTTH coverage (4Q 2020 data) . Since at least 2018, Oi has also been offering IPTV under its FTTH service "Oi Fibra". Also, several regional FTTH providers also offer IPTV along with FTTH internet services.

In 2016, Korean Central Television (KCTV) introduced the set-top box called Manbang, reportedly providing video-on-demand services in North Korea via quasi-internet protocol television (IPTV). Manbang allows viewers to watch five different TV channels in real-time, and find political information regarding the Supreme Leader and Juche ideology, and read articles from state-run news organizations.

Markets

Residential
The global IPTV market was expected to grow from 28 million subscribers at US$12 billion revenue in 2009 to 83 million and US$38 billion in 2013. Europe and Asia are the leading territories in terms of the overall number of subscribers.  But in terms of service revenues, Europe and North America generate a larger share of global revenue, due to very low average revenue per user (ARPU) in China and India, the fastest growing (and ultimately, the biggest markets) is Asia.

Services also launched in Bosnia and Herzegovina, Bulgaria, Pakistan, Canada, Croatia, Lithuania, Moldova, Montenegro, Morocco, North Macedonia, Poland, Mongolia, Romania, Serbia, Slovenia, the Netherlands, Georgia, Greece, Denmark, Finland, Estonia, Czech Republic, Slovakia, Hungary, Norway, Sweden, Iceland, Latvia, Turkey, Colombia, Chile and Uzbekistan. The United Kingdom launched IPTV early and after a slow initial growth, in February 2009 BT announced that it had reached 398,000 subscribers to its BT Vision service. Claro has launched their own IPTV service called "Claro TV". This service is available in several countries in which they operate, such as Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua. IPTV is just beginning to grow in Central and Eastern Europe and Latin America, and now it is growing in South Asian countries such as Sri Lanka, Nepal Pakistan and India. but significant plans exist in countries such as Russia. Kazakhstan introduced its own IPTV services by the national provider Kazakhtelecom JSC and content integrator Alacast under the "iD TV" brand in two major cities Astana and Almaty in 2009 and is about to go nationwide starting 2010. Australian ISP iiNet launched Australia's first IPTV with fetchtv.

In India, IPTV was launched by MTNL, BSNL and Jio in New Delhi, Mumbai and Punjab. APSFL is another IPTV provider in the state of Andhra Pradesh.

In Nepal, IPTV was first launched by NEW IT VENTURE CORPORATION called Net TV Nepal, the service can be accessed through its app, web app and Set top boxes provided by local ISPs, another IPTV was started by Nepal Telecom called WOW Time in 2016 which can be accessed through its app.

In Sri Lanka, IPTV was launched by Sri Lanka Telecom (operated by SLT VisionCom) in 2008, under the brand name of PEO TV. This service is available in whole country. Dialog TV has been available through the service since 2018.

In Pakistan, IPTV was launched by PTCL in 2008, under the brand name of PTCL Smart TV. This service is available in 150 major cities of the country.

In the Philippines, PLDT offers Cignal IPTV services as an add-on in certain ADSL and fiber optic plans.

In Malaysia, various companies have attempted to launch IPTV services since 2005. Failed PayTV provider MiTV attempted to use an IPTV-over-UHF service but the service failed to take off. HyppTV was supposed to use an IPTV-based system, but not true IPTV as it does not provide a set-top box and requires users to view channels using a computer. True IPTV providers available in the country at the moment are Fine TV and DETV. In Q2 2010, Telekom Malaysia launched IPTV services through their fibre to the home product Unifi in select areas.  In April 2010, Astro began testing IPTV services on TIME dotCom Berhad's high-speed fibre to the home optical fibre network. In December 2010, Astro began trials with customers in high-rise condominium buildings around the Mont Kiara area. In April 2011, Astro commercially launched its IPTV services under the tag line "The One and Only Line You'll Ever Need", a triple play offering in conjunction with TIME dotCom Berhad that provides all the Astro programming via IPTV, together with voice telephone services and broadband Internet access all through the same fibre optic connection into the customer's home. In 2020, Astro launched "Plug-and-Play", which uses Unicast technology for streaming TV.

In Turkey, TTNET launched IPTV services under the name IPtivibu in 2010. It was available in pilot areas in the cities of Istanbul, İzmir and Ankara. As of 2011, IPTV service is launched as a large-scale commercial service and widely available across the country under the trademark "Tivibu EV". Superonline plans to provide IPTV under the different name "WebTV" in 2011. Türk Telekom started building the fibre optic substructure for IPTV in late 2007.

Commercial and corporate

IPTV has been widely used since around 2002 to distribute television and audio-visual (AV) media around businesses and commercial sites, whether as live TV channels or Video on Demand (VOD). Examples of types of commercial users include airports, schools, offices, hotels, and sports stadiums, to name just a few.

Architecture

Elements

 IPTV head-end: where live TV channels and AV sources are encoded, encrypted and delivered in the form of IP multicast streams.
 Video on Demand (VOD) platform: where on-demand video assets are stored and served as IP unicast streams when a user makes a request. The VOD platform may sometimes be located with, and considered part of, the IPTV headend.
 Interactive portal: allows the user to navigate within the different IPTV services, such as the VOD catalogue.
 Delivery network: the packet-switched network that carries IP packets (unicast and multicast).
 Endpoints: User equipment that can request, decode and deliver IPTV streams for display to the user. This can include computers and mobile devices as well as set-top boxes.
 Home TV gateway: the piece of equipment at a residential IPTV user's home that terminates the access link from the delivery network.
 User set-top box: the piece of endpoint equipment that decodes and decrypts TV and VOD streams for display on the TV screen.

Architecture of a video server network
Depending on the network architecture of the service provider, there are two main types of video server architecture that can be considered for IPTV deployment: centralised and distributed.

The centralised architecture model is a relatively simple and easy to manage solution. Because all media content is stored in centralised servers, it does not require a comprehensive content distribution system. Centralised architecture is generally good for a network that provides relatively small VOD service deployment, has adequate core and edge bandwidth or has an efficient content delivery network (CDN).

A distributed architecture has bandwidth usage advantages and inherent system management features that are essential for managing a larger server network. Distributed architecture requires intelligent and sophisticated content distribution technologies to augment effective delivery of multimedia contents over the service provider's network.

Residential IPTV home networks
In many cases, the residential gateway that provides connectivity with the Internet access network is not located close to the IPTV set-top box. This scenario becomes very common as service providers start to offer service packages with multiple set-top boxes per subscriber.

Networking technologies that take advantage of existing home wiring (such as power lines, phone lines or coaxial cables) or of wireless hardware have become common solutions for this problem, although fragmentation in the wired home networking market has limited somewhat the growth in this market.

In December 2008, ITU-T adopted Recommendation G.hn (also known as G.9960), which is a next-generation home networking standard that specifies a common PHY/MAC that can operate over any home wiring (power lines, phone lines or coaxial cables).

Groups such as the Multimedia over Coax Alliance, HomePlug Powerline Alliance, Home Phoneline Networking Alliance, and Quasar Alliance (Plastic Optical Fibre) each advocate their own technologies.

Telecomms IMS architecture
There is a growing standardisation effort on the use of the 3GPP IP Multimedia Subsystem (IMS) as an architecture for supporting IPTV services in telecommunications carrier networks. Both ITU-T and ETSI are working on so-called "IMS-based IPTV" standards (see e.g. ETSI TS 182 027). Carriers will be able to offer both voice and IPTV services over the same core infrastructure and the implementation of services combining conventional TV services with telephony features (e.g. caller ID on the TV screen) will become straightforward.

Protocols
IPTV supports both live TV as well as stored video-on-demand. Playback requires a device connected to either a fixed or wireless IP network in the form of a standalone personal computer, smartphone, touch screen tablet, game console, connected TV or set-top box. Content is compressed by Video and audio codecs and then encapsulated in MPEG transport stream or Real-time Transport Protocol or other packets.  IP multicasting allows for live data to be sent to multiple receivers using a single multicast group address. 

In standards-based IPTV systems, the primary underlying protocols used are:
 Service-provider-based streaming:
 IGMP for subscribing to a live multicast stream (TV channel) and for changing from one live multicast stream to another (TV channel change). IP multicast operates within LANs (including VLANs) and across WANs also. IP multicast is usually routed in the network core by Protocol Independent Multicast (PIM), setting up correct distribution of multicast streams (TV channels) from their source all the way to the customers who wants to view them, duplicating received packets as needed.  On-demand content uses a negotiated unicast connection. Real-time Transport Protocol (RTP) over User Datagram Protocol (UDP) or the lower overhead H.222 transport stream over Transmission Control Protocol (TCP) are generally the preferred methods of encapsulation.
 Web-based unicast only live and VoD streaming:
 Adobe Flash Player prefers RTMP over TCP with setup and control via either AMF or XML or JSON transactions.
 Apple iOS uses HLS adaptive bitrate streaming over HTTP with setup and control via an embedded M3U playlist file.
 Microsoft Silverlight uses smooth streaming (adaptive bitrate streaming) over HTTP.
 Web-based multicast live and unicast VoD streaming:
 The Internet Engineering Task Force (IETF) recommends RTP over UDP or TCP transports with setup and control using RTSP over TCP.
 Connected TVs, game consoles, set-top boxes and network personal video recorders:
 Local network content uses UPnP AV for unicast via HTTP over TCP or for multicast live RTP over UDP.
 Web-based content is provided through either inline Web plug-ins or a television broadcast-based application that uses a middleware language such as MHEG-5 that triggers an event such as loading an inline Web browser using an Adobe Flash Player plug-in.

Local IPTV, as used by businesses for audio visual AV distribution on their company networks is typically based on a mixture of:
 Conventional TV reception equipment and IPTV encoders
 TV gateways that receive live Digital Video Broadcasting (DVB) MPEG transport streams (channels) from terrestrial aerials, satellite dishes, or cable feeds and convert them into IP streams

Via satellite
Although IPTV and conventional satellite TV distribution have been seen as complementary technologies, they are likely to be increasingly used together in hybrid IPTV networks. IPTV is largely neutral to the transmission medium, and IP traffic is already routinely carried by satellite for Internet backbone trunking and corporate VSAT networks.

The copper twisted pair cabling that forms the last mile of the telephone and broadband network in many countries is not able to provide a sizeable proportion of the population with an IPTV service that matches even existing terrestrial or satellite digital TV distribution. For a competitive multi-channel TV service, a connection speed of 20 Mbit/s is likely to be required, but unavailable to most potential customers. The increasing popularity of high-definition television increases connection speed requirements or limits IPTV service quality and connection eligibility even further.

However, satellites are capable of delivering in excess of 100 Gbit/s via multi-spot beam technologies, making satellite a clear emerging technology for implementing IPTV networks. Satellite distribution can be included in an IPTV network architecture in several ways. The simplest to implement is an IPTV-direct to home (DTH) architecture, in which hybrid DVB-broadband set-top boxes in subscriber homes integrate satellite and IP reception to give additional bandwidth with return channel capabilities. In such a system, many live TV channels may be multicast via satellite and supplemented with stored video-on-demand transmission via the broadband connection. Arqiva’s Satellite Media Solutions Division suggests "IPTV works best in a hybrid format. For example, you would use broadband to receive some content and satellite to receive other, such as live channels".

Hybrid IPTV

Hybrid IPTV refers to the combination of traditional broadcast TV services and video delivered over either managed IP networks or the public Internet. It is an increasing trend in both the consumer and pay TV markets.

The growth of Hybrid IPTV is driven by two major factors. Since the emergence of online video aggregation sites, like YouTube and Vimeo in the mid-2000s, traditional pay TV operators have come under increasing pressure to provide their subscribers with a means of viewing Internet-based video on their televisions. At the same time, specialist IP-based operators have looked for ways to offer analogue and digital terrestrial services to their operations, without adding either additional cost or complexity to their transmission operations. Bandwidth is a valuable asset for operators, so many have looked for alternative ways to deliver these new services without investing in additional network infrastructures.

A hybrid set-top allows content from a range of sources, including terrestrial broadcast, satellite, and cable, to be brought together with video delivered over the Internet via an Ethernet connection on the device. This enables television viewers to access a greater variety of content on their TV sets, without the need for a separate box for each service. Hybrid IPTV set-top boxes may also enable users to access a range of advanced interactive services, such as VOD, catch-up TV, as well as Internet applications, including video telephony, surveillance, gaming, shopping, e-government accessed via a television set.

From a pay-TV operator's perspective, a hybrid IPTV set-top box gives them greater long-term flexibility to deploy new services and applications as and when consumers require, most often without the need to upgrade equipment or for a technician to visit and reconfigure or swap out the device. This reduces the cost of launching new services, increases speed to market and limits disruption for consumers.

The Hybrid Broadcast Broadband TV (HbbTV) consortium of industry companies the establishment of an open European standard for hybrid set-top boxes for the reception of broadcast and broadband digital TV and multimedia applications with a single user interface. These trends led to the development of Hybrid Broadcast Broadband TV set-top boxes that included both a broadcast tuner and an Internet connection – usually via an Ethernet port. The first commercially available hybrid IPTV set-top box was developed by Advanced Digital Broadcast, a developer of digital television hardware and software, in 2005. The platform was developed for Spanish pay TV operator Telefonica, and used as part of its Movistar TV service, launched to subscribers at the end of 2005.

An alternative approach is the IPTV version of the Headend in the Sky cable TV solution. Here, multiple TV channels are distributed via satellite to the ISP or IPTV provider's point of presence (POP) for IP-encapsulated distribution to individual subscribers as required by each subscriber. This can provide a huge selection of channels to subscribers without overburdening incoming Internet to the POP, and enables an IPTV service to be offered to small or remote operators outside the reach of terrestrial high-speed WAN connection. An example is a network combining fibre and satellite distribution via an SES New Skies satellite of 95 channels to Latin America and the Caribbean, operated by IPTV Americas.

Advantages
The Internet protocol-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.

Interactivity
An IP-based platform also allows significant opportunities to make the TV viewing experience more interactive and personalised. The provider may, for example, include an interactive programme 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 programme 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 favourite show, or even adjust parental controls so their child can watch a documentary for a school report, while they're away from home.

A feedback channel from the viewer to the provider is required for this interactivity. Terrestrial, satellite, and some cable networks for television do not feature a feedback channel and thus don't allow interactivity. However, interactivity with those networks can be possible by combining TV networks with data networks such as the Internet or a mobile communication network.

Video-on-demand
IPTV technology is bringing video on demand (VoD) to television, which permits a customer to browse an online programme or film catalogue, to watch trailers and to then select a selected recording. The playout of the selected item 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 (set-top box 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 is the opportunity for integration and convergence. This opportunity is amplified when using IMS-based solutions. Converged services implies interaction of existing services in a seamless manner to create new value added services. One example is on-screen Caller ID, getting Caller ID on a TV, and the ability to handle it (send it to voice mail, etc.). IP-based services help to enable efforts to provide consumers anytime-anywhere access to content over their televisions, PCs, and mobile device, 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
IPTV is sensitive to packet loss and delays if the streamed data is unreliable. IPTV has strict minimum speed requirements in order to facilitate the right number of frames per second to deliver moving pictures. This means that the limited connection speed and bandwidth available for a large IPTV customer base can reduce the service quality delivered.

Although a few countries have very high-speed broadband-enabled populations, such as South Korea with 6 million homes benefiting from a minimum connection speed of 100 Mbit/s, in other countries (such as the UK) legacy networks struggle to provide 3–5 Mbit/s and so simultaneous provision to the home of TV channels, VOIP and Internet access may not be viable. The last-mile delivery for IPTV usually has a bandwidth restriction that only allows a small number of simultaneous TV channel streams – typically from one to three – to be delivered.

Streaming IPTV across wireless links within the home has proved troublesome; not due to bandwidth limitations as many assume, but due to issues with multipath and reflections of the RF signal carrying the IP data packets. An IPTV stream is sensitive to packets arriving at the right time and in the right order. Improvements in wireless technology are now starting to provide equipment to solve the problem.

Due to the limitations of wireless, most IPTV service providers today use wired home networking technologies instead of wireless technologies like IEEE 802.11. Service providers such as AT&T (which makes extensive use of wireline home networking as part of its AT&T U-verse IPTV service) have expressed support for the work done in this direction by ITU-T, which has adopted Recommendation G.hn (also known as G.9960), which is a next-generation home networking standard that specifies a common PHY/MAC that can operate over any home wiring (power lines, phone lines or coaxial cables).

Latency
The latency inherent in the use of satellite Internet is often held up as reason why satellites cannot be successfully used for IPTV. In practice, however, latency is not an important factor for IPTV, since it is a service that does not require real-time transmission, as is the case with telephony or videoconferencing services.

It is the latency of response to requests to change channel, display an EPG, etc. that most affects customers’ perceived quality of service, and these problems affect satellite IPTV no more than terrestrial IPTV. Command latency problems, faced by terrestrial IPTV networks with insufficient bandwidth as their customer base grows, may be solved by the high capacity of satellite distribution.

Satellite distribution does suffer from latency – the time for the signal to travel up from the hub to the satellite and back down to the user is around 0.25 seconds, and cannot be reduced. However, the effects of this delay are mitigated in real-life systems using data compression, TCP-acceleration, and HTTP pre-fetching.

Satellite latency can be detrimental to especially time-sensitive applications such as on-line gaming (although it only seriously affects the likes of first-person shooters while many MMOGs can operate well over satellite Internet), but IPTV is typically a simplex operation (one-way transmission) and latency is not a critical factor for video transmission.

Existing video transmission systems of both analogue and digital formats already introduce known quantifiable delays. Existing DVB TV channels that simulcast by both terrestrial and satellite transmissions experience the same 0.25-second delay difference between the two services with no detrimental effect, and it goes unnoticed by viewers.

Bandwidth requirements

Digital video is a combination of sequence of digital images, and they are made up of pixels or picture elements. Each pixel has two values, which are luminance and chrominance. Luminance is representing intensity of the pixel; chrominance represents the colour of the pixel. Three bytes would be used to represent the colour of the high quality image for a true colour technique. A sequence of images is creating the digital video, in that case, images are called as frames.

Movies use 24 frames per second; however, the rate of the frames can change according to territories' electrical systems so that there are different kinds of frame rates, for instance, North America is using approximately 30 frames per second where the Europe television frame rate is 25 frames per second. Each digital video has dimensions width and height; when referred to analogue television, the dimension for SDTV is 720×480 pixels, on the other hand, numerous HDTV requires 1920×1080 pixels. Moreover, whilst for SDTV, two bytes (16 bits) is enough to create the colour depth, HDTV requires three bytes (24 bits) to create the colour depth.

Thereby, with a rate of 30 frames/second, the uncompressed data rate for SDTV becomes 30×720×480×16, in other words, 147,456,000 bits per second. Moreover, for HDTV, at the same frame rate, uncompressed date rate becomes 30×1920×1080×24 or 1,492,992,000 bits per second. Using that simple calculation, a service provider's service delivery to the subscribers is limited unless a lossy compression method is used.

There is no absolute answer for the bandwidth requirement for the IPTV service because the bandwidth requirement is increasing due to the devices inside the household. Thus, currently compressed HDTV content can be delivered at a data rate between 8 and 10 Mbit/s, but if the home of the consumer equipped with several HDTV outputs, this rate will be multiplied respectively.

The high-speed data transfer will increase the needed bandwidth for the viewer, at least 2 Mbit/s is needed to use web-based applications on the computer. Additionally to that, 64 kbit/s is required to use landline telephone for the property. In minimal usage, to receive an IPTV triple-play service requires 13 Mbit/s to process in a household.

Privacy implications
Due to limitations in bandwidth, an IPTV channel is delivered to the user one at a time, as opposed to the traditional multiplexed delivery. Changing a channel requires requesting the head-end server to provide a different broadcast stream, much like VOD (For VOD the stream is delivered using unicast, for the normal TV signal multicast is used). This could enable the service provider to accurately track each and every programme watched and the duration of watching for each viewer; broadcasters and advertisers could then understand their audience and programming better with accurate data and targeted advertising.

In conjunction with regulatory differences between IPTV and cable TV, this tracking could pose a threat to privacy according to critics.  For IP multicast scenarios, since a particular multicast group (TV channel) needs to be requested before it can be viewed, the same privacy concerns apply.

Vendors
Global sales of IPTV systems exceeded US$2 billion in 2007, although only a small number of companies supply most current IPTV system solutions. Some, such as Movistar TV, was formed by telecoms operators themselves, to minimize external costs, a tactic also used by PCCW of Hong Kong. Some major telecoms vendors are also active in this space, notably Accenture (Accenture Video Solution), Alcatel-Lucent (sometimes working with Movistar TV), Ericsson (notably since acquiring Tandberg Television), Huawei, NEC, PTCL Smart TV, Sri Lanka Telecom, Thomson, and ZTE, as are some IT houses, led by Microsoft. Miami-based AlphaOTT, Tokyo-based The New Media Group, Malaysian-based Select-TV, Oslo/Norway-based SnapTV, and California-based UTStarcom, Inc. also offer end-to-end networking infrastructure for IPTV-based services, and Hong Kong-based BNS Ltd. provides turnkey open platform IPTV technology solutions.

Hospitality IPTV Ltd, having established many closed network IPTV systems, expanded in 2013 to OTT delivery platforms for markets in New Zealand, Australia, and the Asia Pacific region.

Google Fiber offers an IPTV service in various US cities which includes up to 1 Gigabit-speed internet and over 290 channels depending on package via the fiber optic network being built out in Kansas City Kansas and Kansas City Missouri.

Many of these IPTV solution vendors participated in the biennial Multiservice Switching Forum Interoperability 2008 (GMI) event which was coordinated by the MultiService Forum (MSF) at five sites worldwide from 20 to 31 October 2008. Test equipment vendors including Netrounds, Codenomicon, Empirix, Ixia, Mu Dynamics, and Spirent joined solution vendors such as the companies listed above in one of the largest IPTV proving grounds ever deployed.

Service bundling
For residential users, IPTV is often provided in conjunction with video on demand and may be bundled with Internet services such as Internet access and Voice over Internet Protocol (VoIP) telecommunications services. Commercial bundling of IPTV, VoIP and Internet access is sometimes referred to in marketing as triple play service.  When these three are offered with cellular service, the combined service may be referred to as quadruple play.

Regulation
Historically, broadcast television has been regulated differently from telecommunications. As IPTV allows TV and VoD to be transmitted over IP networks, new regulatory issues arise.
Professor Eli M. Noam highlights in his report "TV or Not TV: Three Screens, One Regulation?" some of the key challenges with sector specific regulation that is becoming obsolete due to convergence in this field.

See also
 Comparison between OTT and IPTV
 Comparison of streaming media systems
 Comparison of video services
 Content delivery network
 Internet television
 List of music streaming services
 List of streaming media systems
 P2PTV
 Protection of Broadcasts and Broadcasting Organizations Treaty
 SAT>IP
 Software as a service
 Streaming media
 TV gateway
 Web television
 Webcast

References

Further reading

Digital television
Film and video technology
Internet broadcasting
Internet radio
Streaming television
Video on demand
Television technology
Television terminology
Computer-related introductions in 1995
Telecommunications-related introductions in 1995
1990s neologisms