definition of Wikipedia
Internet Protocol television (IPTV) is a system through which television services are delivered using the Internet protocol suite over a packet-switched network such as the Internet, instead of being delivered through traditional terrestrial, satellite signal, and cable television formats.
IPTV services may be classified into three main groups:
IPTV is distinguished from Internet television 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.
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 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."
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.
Kingston Communications, a regional telecommunications operator in the UK, launched KIT (Kingston Interactive Television), an IPTV over digital subscriber line (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 VoD content provider. Kingston was one of the first companies in the world to introduce IPTV and IP VoD over ADSL.  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 Internet Protocol (IP) video over DSL, using the Lucent Stinger DSL platform. In 2006, it was the first North American company to offer high-definition television (HDTV) channels over an IPTV service.
In 2003, Total Access Networks Inc launched an IPTV service, consisting of 100 free IPTV stations worldwide. The service has been used in over 100 countries worldwide, and has channels in 26 languages.
In 2005, Bredbandsbolaget launched its IPTV service as the first service provider in Sweden. As of January 2009, they are not the biggest supplier any longer; TeliaSonera, who launched their service later now has more customers.
In 2006, AT&T launched its U-Verse IPTV service in the United States, comprising 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. In March 2009, AT&T announced that U-verse had expanded to 100 or more high-definition channels in every U-Verse TV market. While using Internet protocols, AT&T built a private IP network exclusively for video transport.
The Bell Video Store was a premium Internet video-on-demand service offered by Bell Sympatico in Canada. It began service in May 2007, under a cloud of controversy as Bell Sympatico had just begun throttling internet speeds for its customers. The Bell Video Store ceased operations in July 2009.
In 2007 TPG became the first internet service provider in Australia to launch IPTV. Complementary to its ADSL2+ package this was, and still is, free of charge and now offers over 45 local free to air channels and international channels. By 2010, iiNet and Telstra launched IPTV services in conjunction to internet plans but with extra fees.
The technology was restricted[when?] by low broadband penetration and by the relatively high cost of installing wiring capable of transporting IPTV content reliably in the customer's home. However, residential IPTV was expected to grow[original research?] as broadband was available to more than 200 million households worldwide in 2005.
In December 2009, the FCC began looking into using set-top boxes to make TVs with cable or similar services into network video players. FCC Media Bureau Chief Bill Lake had said earlier that TV and the Internet would soon be the same, but only 75 percent of homes had computers, while 99 percent had TV. A 2009 Nielsen survey found 99 percent of video viewing was done on TV.
In an interview with Beet.TV, Cisco’s VP for Marketing and Emerging Technologies, David Hsieh, points out that “video is invading all aspects of our lives.” He says, “Today over half of all Internet traffic is video—51 percent. November 1, 2011 4:45 PM
The number of global IPTV subscribers was expected to grow from 28 million in 2009 to 83 million in 2013. Europe and Asia are the leading territories in terms of the over-all 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. The global IPTV market revenues are forecast to grow from US$12 billion in 2009 to US$38 billion in 2013.
While all major western countries and most developed economies have IPTV deployments, the world's leading markets for IPTV were Germany (by Deutsche Telekom) France (led by Free, then Orange, then Neuf Cegetel (now SFR); total of over 4 million subscriptions), South Korea (4 million subscriptions as of May 2011), United States (by AT&T), Hong Kong, Japan, Italy, Spain, Belgium, Luxembourg, Austria, China, Singapore, Taiwan, Switzerland and Portugal (with meo, Optimus Clix and Vodafone Casa).
Services also launched in Bosnia and Herzegovina, Pakistan, Canada, Croatia, Lithuania, Republic of Moldova, Macedonia, Montenegro, Poland, Mongolia, Romania, Serbia, Slovenia, the Netherlands, Georgia, Greece, Denmark, Finland, Estonia, Czech Republic, Slovakia, Hungary, Norway, Sweden, Iceland, Lithuania, Turkey, Colombia and Chile. 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, Pakistan and especially 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.[dated info] Australian ISP iiNet launched Australia's first IPTV with fetchtv.
The first IPTV service to launch on the Chinese mainland sells under the "BesTV" brand and is currently available in the cities of Shanghai and Harbin. In India, IPTV was launched by Airtel and the government service provider MTNL and BSNL and is available in most of the major cities of the country. Meanwhile, UF Group which is the franchise owner for UFO movies in Southern India plans to offer multiple host of services such as customer's movies on demand, shopping online, video conferencing, media player, e-learning on their single IPTV set top box branded as Emagine. In Pakistan, IPTV was launched by PTCL, under brand name Smart TV, which is available in most of the major cities of Pakistan.
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. Hypp.TV 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 fiber to the home product UniFi in select areas. In April 2010, Astro began testing IPTV services on TIME dotCom Berhad's high-speed fiber 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 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 fiber optic substructure for IPTV in late 2007.
Besides targeting the homes, vendors target IPTV services to the hospitality sector. IPTV is a natural progression from the pay-per-view and video on demand offerings. Some players such as Select-TV and VDA have started offering IPTV to the hotels before moving into the homes.
|Common name||IEEE standard|
|Common name||ITU-T recommendation|
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: centralized and distributed.
The centralized architecture model is a relatively simple and easy to manage solution. For example, as all contents are stored in centralized servers, it does not require a comprehensive content distribution system. Centralized architecture is generally good for a network that provides relatively small VOD service deployment, has adequate core and edge bandwidth and has an efficient content delivery network (CDN).
Distributed architecture is just as scalable as the centralized model, however it has bandwidth usage advantages and inherent system management features that are essential for managing a larger server network. Operators who plan to deploy a relatively large system should therefore consider implementing a distributed architecture model right from the start. Distributed architecture requires intelligent and sophisticated content distribution technologies to augment effective delivery of multimedia contents over service provider's network.
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.
Traditional home networking technologies such as Ethernet and 802.11 do not provide a good solution to provide connectivity between the gateway and each set-top box. Most homes today are not wired with Ethernet cable in every room, and installing new Ethernet cables is expensive. Wireless technologies like 802.11 don't always provide the quality of service required by IPTV applications. A new technology, though, has been lately being offered as an alternative to the Ethernet copper new wires installation, it is POF (Plastic Optical Fiber). POF enjoys the fact that it is a dielectric medium to allow the routing using the existing home mains ducts and thus reducing the cost and disturbance of a new installation. Today´s POF networking products allow speeds up to 200 Mbit/s for typical home applications with Gigabit products announced by the end of 2012. Several IPTV operators are already running field trials to evaluate POF as an alternative for Home Networking,
Networking technologies that take advantage of existing home wiring (such as power lines, phone lines or coaxial cables) have become a popular solution 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). During 2012 IEC will adopt a prenorm for POF networking at Gigabit speed. This pre standard will specify a PHY that operates at an adaptable bit rate between 100 Mbit/s and 1 Gbit/s depending on the link power budget.
There is a growing standardization effort on the use of the 3GPP IP Multimedia Subsystem (IMS) as an architecture for supporting IPTV services in carriers 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. The MultiService Forum recently conducted interoperability of IMS-based IPTV solutions during its GMI event in 2008.
IPTV covers both live TV (multicasting) as well as stored video (video-on-demand, or VoD). The playback of IPTV requires an IP connected device, typically a personal computer or smart phone, or tablet, or game-console, or the traditional 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 H.264 (MPEG-4) codec is increasingly used to replace the older MPEG-2 codec.
In standards-based IPTV systems, the primary underlying protocols used are:
A telecommunications company IPTV service is usually delivered over an investment-heavy walled garden network.
Local IPTV, as used by businesses for audio visual AV distribution on their company networks is typically based on a mixture of:
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 that deliver the highest levels of performance and reliability. 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 use of satellite to carry IP is fundamental to overcoming the greatest shortcoming of IPTV over terrestrial cables – the speed/bandwidth of the connection.
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 (with twice the data rate of SD video) 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 near-infinite bandwidth with return channel capabilities. In such a system, many live TV channels may be multicast via satellite (IP-encapsulated or as conventional DVB digital TV) 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”.
||This article's factual accuracy may be compromised due to out-of-date information. (July 2011)|
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 [operator] markets.
Hybrid IPTV has grown in popularity in recent years[when?] as a result of two major drivers. 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 [both professional and user-generated] on their televisions. At the same time, specialist IP-based operators [often telecommunications providers] 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 also enable users to access a range of advanced interactive services, such as VOD and 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 by enabling them to deploy new services and applications as and when consumers require, most often without the need to upgrade equipment or for an engineer to visit and reconfigure or swap out the device. This minimises 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 is currently[when?] promoting and establishing 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 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 Imagenio 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 Internet trunking to the POP, and enables an IPTV service to be offered to small or remote operators outside the reach of terrestrial high speed broadband 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.
While the future development of IPTV probably lies with a number of coexisting architectures and implementations, it is clear[says who?] that broadcasting of high bandwidth applications such as IPTV is accomplished more efficiently and cost-effectively using satellite and it is predicted that the majority of global IPTV growth will be fuelled by hybrid networks.
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. 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.
The cable industry's expenditures of approximately $1 billion per year are based on network updates to accommodate higher data speeds. Most operators use 2–3 channels to support maximum data speeds of 50 Mbit/s to 100 Mbit/s. However, because video streams require a high bit rate for much longer periods of time, the expenditures to support high amounts of video traffic will be much greater. This phenomenon is called persistency. Data persistency is routinely 5% while video persistency can easily reach 50%. As video traffic continues to grow, this means that significantly more CMTS downstream channels will be required to carry this video content. Based on today's market, it is likely that industry expenditures for CMTS expansion could exceed $2 billion a year, virtually all of that expenditure being driven by video traffic. Adoption of IPTV for carrying the majority of this traffic could save the industry approximately 75% of this capital expenditure.
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. In order that there can take place an interaction between the receiver and the transmitter, a feedback channel is needed. Due to this, terrestrial, satellite, and cable networks for television do not 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.
IPTV technology is bringing video-on-demand (VoD) to television, which permits a customer to browse an online program or film catalog, 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).
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.
Another advantage of an IP-based network 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 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.
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[who?] 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[when?] 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 802.11. Service providers such as AT&T (which makes extensive use of wireline home networking as part of its 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).
The latency inherent in the use of satellite Internet is often held up as reason why satellites cannot be successfully used for IPTV, but in practice latency is not an important factor for IPTV. An IPTV service 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.
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 date rate for SDTV becomes 30×640×480×16, 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. With that simple calculation, it is obvious that without using a lossy compression methods service provider’s service delivery to the subscribers is limited.
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.
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.
A small number of companies supply most current IPTV systems. Some, such as Imagenio, were formed by telecoms operators themselves, to minimise external costs, a tactic also used by PCCW of Hong Kong. Some major telecoms vendors are also active in this space, notably Alcatel-Lucent (sometimes working with Imagenio), Ericsson (notably since acquiring Tandberg Television), NEC, Nokia Siemens Networks, Thomson, Huawei, and ZTE, as are some IT houses, led by Microsoft. California-based UTStarcom, Inc., Tennessee-based Worley Consulting, Tokyo-based The New Media Group, Malaysian-based Select-TV and Oslo/Norway-based SnapTV also offer end-to-end networking infrastructure for IPTV-based services, and Hong Kong-based BNS Ltd. provides turnkey open platform IPTV technology solutions. Global sales of IPTV systems exceeded 2 billion USD in 2007.
Many of these IPTV solution vendors participated in the biennial Global MSF 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 Absilion, 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.
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.
Historically, broadcast television has been regulated differently than 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.
Dictionary and translator for handheld
New : sensagent is now available on your handheld
A windows (pop-into) of information (full-content of Sensagent) triggered by double-clicking any word on your webpage. Give contextual explanation and translation from your sites !
With a SensagentBox, visitors to your site can access reliable information on over 5 million pages provided by Sensagent.com. Choose the design that fits your site.
Improve your site content
Add new content to your site from Sensagent by XML.
Crawl products or adds
Get XML access to reach the best products.
Index images and define metadata
Get XML access to fix the meaning of your metadata.
Please, email us to describe your idea.
Lettris is a curious tetris-clone game where all the bricks have the same square shape but different content. Each square carries a letter. To make squares disappear and save space for other squares you have to assemble English words (left, right, up, down) from the falling squares.
Boggle gives you 3 minutes to find as many words (3 letters or more) as you can in a grid of 16 letters. You can also try the grid of 16 letters. Letters must be adjacent and longer words score better. See if you can get into the grid Hall of Fame !
Change the target language to find translations.
Tips: browse the semantic fields (see From ideas to words) in two languages to learn more.
last searches on the dictionary :
computed in 1.077s