What is IPTV?

IPTV stands for Internet Protocol TV. An IPTV system deployed within a business enables hundreds of channels of TV and video to be viewed on an unlimited number of TVs and PCs connected to your existing data network.

 

 

Why use IPTV for TV distribution?

By using an IPTV solution to stream TV and video over your data network, wherever you have a network outlet you can connect a TV or a PC to display the channels you choose and control.

IPTV systems distribute TV and video from any source. Satellite TV, Freeview TV, studio outputs, pre recorded educational and trainingprograms and corporate broadcasts are all displayed consistently at the highest quality at all points thanks to digital technology.

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Television is changing

Over the last decade, the growth of satellite service, the rise of digital cable, and the birth of HDTV have all left their mark on the television landscape. Now, a new delivery method threatens to shake things up even more powerfully. Internet Protocol Television (IPTV) has arrived, and backed by the deep pockets of the telecommunications industry, it's poised to offer more interactivity and bring a hefty dose of competition to the business of selling TV.

IPTV describes a system capable of receiving and displaying a video stream encoded as a series of Internet Protocol packets.

If you've ever watched a video clip on your computer, you've used an IPTV system in its broadest sense. When most people discuss IPTV, though, they're talking about watching traditional channels on your television, where people demand a smooth, high-resolution, lag-free picture, and it's the telcos that are jumping headfirst into this market. Once known only as phone companies, the telcos now want to turn a "triple play" of voice, data, and video that will retire the side and put them securely in the batter's box.

In this primer, we'll explain how IPTV works and what the future holds for the technology. Though IP can (and will) be used to deliver video over all sorts of networks, including cable systems, we'll focus in this article on the telcos, which are the most aggressive players in the game.

They're pumping billions into new fiber rollouts and backend infrastructure (AT&T alone inked a US$400 million deal for Microsoft's IPTV Edition software last year, for instance, and a US$1.7 billion deal with hardware maker Alcatel). Why the sudden enthusiasm for the TV business? Because the telcos see that the stakes are far higher than just some television: companies that offer the triple play want to become your household's sole communications link, and IPTV is a major part of that strategy.

How it works

First things first: the venerable set-top box, on its way out in the cable world, will make a resurgence in IPTV systems. The box will connect to the home DSL line and is responsible for reassembling the packets into a coherent video stream and then decoding the contents. Your computer could do the same job, but most people still don't have an always-on PC sitting beside the TV, so the box will make a comeback. Where will the box pull its picture from? To answer that question, let's start at the source.

Most video enters the system at the telco's national headend, where network feeds are pulled from satellites and encoded if necessary (often in MPEG-2, though H.264 and Windows Media are also possibilities). The video stream is broken up into IP packets and dumped into the telco's core network, which is a massive IP network that handles all sorts of other traffic (data, voice, etc.) in addition to the video.

Here the advantages of owning the entire network from stem to stern (as the telcos do) really come into play, since quality of service (QoS) tools can prioritize the video traffic to prevent delay or fragmentation of the signal. Without control of the network, this would be dicey, since QoS requests are not often recognized between operators.

With end-to-end control, the telcos can guarantee enough bandwidth for their signal at all times, which is key to providing the "just works" reliability consumers have come to expect from their television sets.

The video streams are received by a local office, which has the job of getting them out to the folks on the couch. This office is the place that local content (such as TV stations, advertising, and video on demand) is added to the mix, but it's also the spot where the IPTV middleware is housed. This software stack handles user authentication, channel change requests, billing, VoD requests, etc.—basically, all of the boring but necessary infrastructure.

All the channels in the lineup are multicast from the national headend to local offices at the same time, but at the local office, a bottleneck becomes apparent. That bottleneck is the local DSL loop, which has nowhere near the capacity to stream all of the channels at once. Cable systems can do this, since their bandwidth can be in the neighborhood of 4.5Gbps, but even the newest ADSL2+ technology tops out at around 25Mbps (and this speed drops quickly as distance from the DSLAM [DSL Access Multiplier] grows).

So how do you send hundreds of channels out to an IPTV subscriber with a DSL line? Simple: you only send a few at a time. When a user changes the channel on their set-top box, the box does not "tune" a channel like a cable system. (There is in fact no such thing as "tuning" anymore—the box is simply an IP receiver.)

What happens instead is that the box switches channels by using the IP Group Membership Protocol (IGMP) v2 to join a new multicast group. When the local office receives this request, it checks to make sure that the user is authorized to view the new channel, then directs the routers in the local office to add that particular user to the channel's distribution list.

In this way, only signals that are currently being watched are actually being sent from the local office to the DSLAM and on to the user.

No matter how well-designed a network may be or how rigorous its QoS controls are, there is always the possibility of errors creeping into the video stream. For unicast streams, this is less of an issue; the set-top box can simply request that the server resend lost or corrupted packets.

With multicast streams, it is much more important to ensure that the network is well-engineered from beginning to end, as the user's set-top box only subscribes to the stream—it can make no requests for additional information. To overcome this problem, multicast streams incorporate a variety of error correction measures such as forward error correction (FEC), in which redundant packets are transmitted as part of the stream.

Again, this is a case where owning the entire network is important since it allows a company to do everything in its power to guarantee the safe delivery of streams from one end of the network to the other without relying on third parties or the public Internet.

Though multicast technology provides the answer to the problem of pumping the same content out to millions of subscribers at the same time, it does not help with features such as video on demand, which require a unique stream to the user's home. To support VoD and other services, the local office can also generate a unicast stream that targets a particular home and draws from the content on the local VoD server. This stream is typically controlled by the Real Time Streaming Protocol (RTSP), which enables DVD-style control over a multimedia stream and allows users to play, pause, and stop the program they are watching.

The actual number of simultaneous video streams sent from the local office to the consumer varies by network, but is rarely more than four. The reason is bandwidth. A Windows Media-encoded stream, for instance, takes up 1.0 to 1.5Mbps for SDTV, which is no problem; ten channels could be sent at once with bandwidth left over for voice and data. But when HDTV enters the picture, it's a different story, and the 20-25Mbps capacity of the line gets eaten up fast. At 1080i, HDTV bit rates using Windows Media are in the 7 to 8 Mbps range (rates for H.264 are similar). A quick calculation tells you that a couple of channels are all that can be supported.

The bandwidth situation is even worse when you consider MPEG-2, which has lower compression ratios. MPEG-2 streams will require almost twice the space (3.5 Mbps for SDTV, 18-20 Mbps for HDTV), and the increased compression found in the newer codecs is one reason that AT&T will not use MPEG-2 in the rollout of its IPTV service dubbed "U-verse."

Simultaneous delivery of channels is necessary to keep IPTV competitive with cable. Obviously, multiple streams are needed to support picture-in-picture, but they're also needed by DVRs, which can record one show while a user is watching another. For IPTV to become a viable whole-house solution, it will also need to support enough simultaneous channels to allow televisions in different rooms to display different content, and juggling resulting bandwidth issues is one of the trickiest parts of implementing an IPTV network that will be attractive to consumers.

Internet Protocol Television (IPTV) is digital television delivered on your television (and not PC) through high speed internet (broadband) connection. In this service, channels are encoded in IP format and delivered to the TV through a set top box. IPTV service also includes video on demand, which is similar to watching video CDs/DVDs using a VCD/DVD player.

How does it work?

IPTV converts a television signal into small packets of computer data like any other form of online traffic such as email or a web page. There are three main components of IPTV. First, the TV and content head end, where the TV channels are received and encoded and also other content like videos which are stored. The second component is the delivery network, which is broadband and landline network provided by a telecom operators such as MTNL.

What are the advantages of IPTV?

The quality of digital video and audio is much better compared with the traditional analogue TV. With additional features, it can become interactive. For example, viewers may be able to look up a player's history while watching a game. They also may be able to schedule a recording of their favourite programme when they are not home. With video on demand, they can browse an online movie catalogue and watch the movies instantly.

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 cable.

What are the limitations of IPTV?

Because IPTV is based on internet protocol, it is sensitive to packet loss and delays if the IPTV connection is not fast enough.

When was IPTV service first used?

In 1994, ABC's World News Now was the first television show to be broadcast over the internet, using the CU-SeeMe video conferencing software. Internet radio company AudioNet started the first continuous live webcast in January, 1998.

When was IPTV rolled out in India?

Public sector operator Mahanagar Telephone Nigam (MTNL) is the first and only telco in India providing IPTV services. It rolled out IPTV early this month in Mumbai and Delhi. The original 26 channels it launched were free-to-air, while the new lineup includes premium subscription channels. It has not yet announced tariff plans, which will vary depending on the number of channels a user subscribes to and the use of premium services.

Who are the other telcos planning IPTV services?

Bharti Airtel is readying for launch while Reliance Communications has also been undertaking trials for IPTV for over a year now. BSNL is expected to roll it out by January next year. Since IPTV is delivered through landline connection, telcos like Hutchison Essar and Idea Cellular will not be able to offer the service right now as they do not have fixed line networks.

For many people technological innovation is moving at such a rapid rate that it is difficult to figure out what is capable of doing what, and what is science fiction and what is useful.

IPTV is a somewhat recent technology, and one that's both extremely useful and difficult to get your head around - particularly if you aren't a 'techie'. Nevertheless, it is truly worth trying to figure it out as it's all around us daily and no doubt it's going to only grow in the future.

So what is IPTV?

IPTV or internet protocol television, is actually a way of transporting Audio and Video (AV) and many other components of digital data information throughout an Internet Protocol based network. To many people that will seem like technical mumbo-jumbo so let's look at what IPTV may offer in the real world.

This technology is all around us and being utilised in various ways each day. For instance, do you know that the BBC's iPlayer works by using IPTV at its core? Without a doubt a number of other web based video streaming providers will also be utilising this technology. A really different example of it in day-to-day use is digital signage. These are those high-tech information or marketing and advertising displays that are now popular at airport terminals, train stations and sporting events. These electronic digital signs tend to be slick in features and very efficient in operation.

Hotels, Healthcare and Education

If you have ever checked out of your hotel room by paying the balance using the Television display in the room, you have most probably taken advantage of an IPTV service supplied by the hotel. This is a superb demonstration of how useful and convenient technology can often be to everyone.

More and more places of education are also making use of the technology simply because it has tremendous benefits for transmitting lesson information, documentaries and videos to desktop PCs and screens all through the school or college. Video information might be stored and recalled at any time by any member of staff or student (where access is granted). This is unquestionably starting to be essential to the current learning environment.

Within the health care marketplace the benefits are also substantial. Hugely versatile and sophisticated entertainment and communication facilities can be easily accessed by patients which obviously is a real asset to any health care environment.

Hopefully the brief descriptions previously mentioned of the uses and advantages of IP TV in a variety of daily scenarios, will help you understand the fundamentals of what it offers. Once you peel back all of the complicated networking protocols associated you are left with a genuinely useful and impressive way of communication, entertainment and education.