It has already happened to millions of people in Sweden, Finland, Switzerland, Luxembourg and the Netherlands, and in the next few years hundreds of millions more across the globe should have the same experience: their TV picture will quite suddenly - and very permanently - disappear. No amount of shouting, bashing the box, or fiddling with the aerial will get the picture back, because after half a century of service, analogue TV broadcasts are being switched off for good.
Most of us, of course, won't notice, having switched to digital TV services such as the UK's Freeview years ago. Analogue TV sets, and the transmitters that have kept them glowing, are giving way to new ones fed by digital transmitters capable of simultaneously beaming out dozens of programmes where once there was just a handful. This is the age of high-definition TV pictures with CD-quality sound, video-on-demand and a host of other interactive services. Yet TV is already undergoing other, more radical changes - not least a migration from the airwaves to the internet. By the time the last analogue transmitters in Europe and the US are switched off in around 2012, many of us are likely to be too busy watching TV on our computers or cellphones to even care. So what will technology bring to the way we watch television? Will the internet render today's brand-new digital transmitters obsolete within just a few years? And can these changes deliver all that they promise? There certainly are good reasons for going digital, one of the most important for viewers being picture quality. While analogue broadcasters transmit programmes by modulating very high frequency radio waves, digital broadcasting encodes pictures and sound in streams of 1s and 0s. This largely eliminates interference and the picture degradation it causes. Another plus is that more information can be squeezed into the same frequency bandwidth, allowing broadcasters to provide pictures with far higher definition, as well as data channels - electronic programme guides or interactive services, for example. This allows broadcasts to be used in a variety of ways. As well as live viewing, they can be recorded and stored on computers or set-top boxes, or transmitted across the internet. Video-on-demand services, delivered by satellite or cable, mean we no longer need to make a trip to the local video rental store. There are already thousands of online TV channels available, offering pre-recorded news, sport and other video, as well as some live programmes. Cellphone networks are experimenting with the technology, too. In February, for example, a consortium of operators announced a new mobile TV trial in west London. It will deliver up to 24 digital TV channels to customers' mobile phones. Other companies are taking a more holistic approach. Sling Media, for example, is combining technologies so that viewers can not only pause and rewind live TV but can also watch programmes stored on their home computer from anywhere in the world, using a laptop or mobile phone. Several manufacturers have unveiled TVs with dedicated internet connections, allowing viewers to switch to internet TV at the push of a button. There are a number of new display technologies on the horizon too (see "Tomorrow's TV"). So far, audiences seem reasonably open to these new ways to watch TV. In May 2006, around 11 million viewers watched a new episode of the hit TV series Lost when it ran online. The following month, market analysts Jupiter Research reported that around 11 per cent of computer users regularly watch videos on the internet. A year later, this figure had jumped to 28 per cent, boosted perhaps by the dramatic growth in popularity of sites like YouTube. Yet because of the volume and speed of data required, the internet still has some way to go before it can offer high-quality live transmissions. This problem will need to be solved if the internet is to compete with the old faithful TV. At present, the pre-recorded programmes available online are of relatively poor quality and have sluggish download speeds. The low resolution is particularly noticeable if you transfer a downloaded movie from your computer to your TV - as you can with Apple's online TV service, for example. Indeed, for those who have spent a small fortune on the latest high-definition, flat-screen TV, online video delivery will prove rather disappointing. The fundamental problem is that TV-quality images take up thousands of times more bytes than email or the music files we usually send via the internet. To watch one TV-quality episode of your favourite soap, for instance, you'd need to download a data package of around 300 megabytes. The internet was designed for point-to-point information exchange - from a server or service provider to the user - so how can it support the streams of massive files that a high-quality, "live" online TV service would require, without grinding to a halt? Solving this problem necessitates a radical transformation of the way pictures are transmitted. One London-based company, Skinkers, claims to have found a solution. Together with Microsoft, it has taken peer-to-peer (P2P) architecture - which has already proved its worth with music file-sharing services such as Kazaa - and developed a new kind that allows high-quality video to be broadcast live over the internet, hopefully without clogging up connections. Rather than relying on a single server to send video to potentially millions of viewers, Skinkers' software - called Livestation - connects viewers' computers to form P2P networks. Once registered, viewers choose which channels they want to receive. Livestation then sends each viewer small packages of their selected channels. By swapping chunks with nearest neighbours, each viewer can then receive a complete broadcast. Each networked computer, or node, is given an identifying number that allows Livestation to keep track of the content stored on it and where its nearest neighbours are. By organising computers into a series of decentralised networks - one for each channel - and by sending programmes out as small chunks of data to a large number of viewers, Livestation creates a fault-tolerant system that can cope with large files, different upload and download rates and unreliable connections. Livestation is currently undergoing trials and Skinkers eventually plans to sell it to broadcasters so they can transmit their programmes across the net. This isn't the first time P2P networks have been used to exchange video. Joost, a video-on-demand service launched by the founders of the P2P internet phone service Skype, uses this kind of network, though so far all footage is pre-recorded rather than live. The distinction is important to broadcasters, who see live news, music or sport events as the key to the success of online TV. There is one company already offering live TV on the internet. San Francisco-based Zattoo uses a P2P system developed by Sugih Jamin, a computer scientist at the University of Michigan at Ann Arbor. It offers more than a dozen live channels - at less than TV-quality - to online viewers in Europe, including several channels from the BBC. According to company spokesperson Helen Boch, Zattoo already has 1.7 million users, and it expects to add further channels this spring. If broadcasting programmes across the internet seems difficult, then creating a TV service for mobile phones might seem impossible. As well as being on the move, which makes downloading a constant flow of data more difficult, handsets have limited battery power, and downloading data can use plenty of juice. At present, viewers need access to a high-speed data connection such as 3G to receive a service. Even then, if more than a handful of people in one area use the service at the same time, the network slows to a crawl. There is some good news for mobile TV fans, though. Phone manufacturers have agreed an international digital video broadcast standard for handsets - DVB-H - that will bring mobile phone users their own digital broadcasts, in most cases delivered by the same transmitters that broadcast terrestrial digital TV, rather than through mobile phone networks. This technology enables content to be broadcast simultaneously to an unlimited number of handsets - those equipped with new digital receivers, that is - in the same way that we receive conventional digital TV. Early trials have proved successful: the first service, launched in Italy in 2006, gained 600,000 subscribers within 12 months. Yet it looks as though the future of digital television in the living room is secure for the moment. After all, it promises high-definition programming, and there's little point watching high-definition TV on a small handset or computer screen. What's more, given the 25 gigabytes of data needed to transmit a 2-hour HDTV movie, streaming this to large numbers of viewers is just not viable with the current speed of the internet - not even across P2P networks. There is one fly in the ointment for digital TV, however. HDTV cannot be rolled out to every viewer until analogue TV broadcasts are switched off - there simply isn't enough space on the airwaves. And this could give internet and mobile phone TV a head start of several years to hook an audience. Whatever happens, this will be one drama worth watching. To unsubscribe send a message to accessindia-requ...@accessindia.org.in with the subject unsubscribe. To change your subscription to digest mode or make any other changes, please visit the list home page at http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in
