YOU HAVE probably tried it. You are away from home and want to catch up with the news. The BBC World Service broadcasts on one of the short-wave bands, so you find a suitable radio and try to tune in. If you are lucky you鈥檒l hear a voice from London through the hiss and whine of interference. But as often as not the attempt will fail. Reception conditions are wrong, or it鈥檚 the wrong time of day, or your radio simply isn鈥檛 up to the task. It鈥檚 the same story if you are at home in Britain and want to tune in to news from abroad.
There has to be a better way. Over the past few months a group of companies have started to exploit the Internet to make local radio global. One of the pioneers of Internet broadcasting is the London-based World Radio Network, which relays programmes from stations in some 25 countries via satellite and cable, as well as over the Net. Jeff Cohen, WRN鈥檚 director of development, says that what many people want when they log on is international news.
鈥淧eople on the West Coast of the US, for example, find it difficult to pick up short-wave transmissions from Europe,鈥� says Cohen. There seems to be particular interest in the service from Eastern Europeans now living in the US, who want to stay in contact with their home countries 鈥� often to keep up to date with potential business opportunities.
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Island research
Cohen has also found academics showing a lot of interest. 鈥淥ne US researcher who specialises in the economics of Pacific islands can now get much of the information he requires by logging into WRN and listening to Australian Radio.鈥� Newspaper reports could take weeks to arrive at his US university campus, and radio broadcasts are not easy to pick up. Further down the educational ladder, schoolteachers are getting their pupils to investigate how different countries report events of international interest, such as the recent French nuclear tests in the South Pacific. WRN鈥檚 output comes from mainstream national broadcasters around the world, from the US to Korea and Australia to Finland. On its World Wide Web site there are two live streams: WRN1 broadcasts in English 24 hours a day, while WNR2 carries programmes in a variety of languages. Cohen says that WRN鈥檚 Web server gets about 14 000 hits a week from people who want to listen in on their computers.
Of course, there is nothing new about sound on the Internet. Since the mid-1980s, it has been possible to save digitised audio in files and send them over the Internet using standards devised by companies like Sun Microsystems and Microsoft. In 1992, Carl Malamud an early exponent of Net culture realised that these standards could be used to distribute radio programmes, and founded the Internet Multicasting Service. For two years, IMS broadcast American National Press Club meetings, National Public Radio鈥檚 TechNation programme and Malamud鈥檚 own Geek of the Week show via the Internet.
The problem was that the data files were vast. An hour of programming took up 30 megabytes 鈥� enough to fill the hard discs of all but the most expensive workstations of that time 鈥� or about 100 000 bits for each second of sound. This meant that only those people with a fast Internet link could listen in real time 鈥� and that meant people at universities and major corporations. Anyone using a modem and phone lines would have had to spend hours downloading the files, and then play them back later. This cumbersome process could not begin to compete with the handy transistor radio. It needed to be made much simpler, and to work in real time.
But Internet broadcasting has now been brought to life for people who rely on a modem link by a program called RealAudio, produced by the Seattle-based company Progressive Networks. RealAudio鈥檚 trick is to make data transmission more efficient by cutting out some of the Internet鈥檚 time-consuming customs. Audio normally needs a lot more data capacity, or 鈥渂andwidth鈥�, than modems and phone lines can support: to get the sort of sound we have come to expect from an audio compact disc takes about 50 000 bits per second. The fastest modems in common use today can only transmit 28 800 bps, and only if the phone lines are performing perfectly. For most people, the maximum is more like 10 000 bps. Though this is not enough for high-fidelity music, it is adequate for speech with a quality comparable to that of AM radio.
But to get sound into this narrow bandwidth, RealAudio has to break the rules normally used for transmitting data over the Net 鈥� the Transmission Control Protocol, or TCP, which was designed to ensure that no data gets lost in transmission. According to John Shay, RealAudio鈥檚 product manager, computers using TCP communicate in much the same way that people using CB radio do. Each party in a two-way conversation acknowledges what the other has said. When one person speaks, the other has to respond by saying 鈥淩oger鈥� to acknowledge receipt, or 鈥淐ome back on that鈥� to make them repeat what was said.
The trouble with TCP, says Shay, is that all of this acknowledgement eats up bandwidth. The Internet divides messages into small chunks or 鈥減ackets鈥�. Acknowledging that each one has arrived typically almost doubles the amount of data that needs to be sent. And if one of the thousands of packets of information that makes up an audio transmission is not delivered, or is delivered incompletely, it must be rebroadcast. This is all a waste of bandwidth when it comes to real-time transmission. 鈥淲e do live broadcasting,鈥� Shay points out. 鈥淚f a packet shows up late, it might as well have not shown up at all.鈥�
To avoid the acknowledgements, RealAudio uses the much less rigorous User Datagram Protocol. 鈥淯DP is more like each packet being a postcard,鈥� says Shay. 鈥淚f you mail a hundred postcards, numbered 1 through 100, the post office will try to get them to their destination. But it doesn鈥檛 guarantee that the cards will get there in order, or get there unshredded, or even that they鈥檒l all get there at all. It鈥檚 up to the person receiving the postcards to get them and reorder them, check to see if the information on each postcard hasn鈥檛 been destroyed or mangled, and deal with lost postcards.鈥�
And what about those 鈥渓ost postcards鈥� 鈥� the packets of information that never make it to their destination? RealAudio is designed with the expectation that some of those packets will get lost. If it doesn鈥檛 receive packet number 211, say, it will make its best guess at what was in that packet by analysing the contents of packets 210 and 212. A buffer is built into the software to help iron out delays. These result from packets being held up on one of the Internet鈥檚 routing computers, and the need to assemble the packets into the correct order.
On days when the Internet isn鈥檛 performing well, this results in tinny, distorted sound, but most of the time speech comes across clearly. Since the software was released last April, nearly a million people have downloaded it, making it by far the most popular way to receive sound over the Net.
But it is not the only one. For its live broadcasts, WRN is experimenting with a system called Streamworks from Xing Technologies of San Luis Obispo, California. This software uses the standard TCP/IP rules for transferring data, while compressing the files on the fly using the MPEG compression scheme for audio. Xing鈥檚 software comes loaded on a PC with four or more output channels. Using a special distribution device, it is possible to take the output from any one of these channels and repeat it so there are multiple channels of the same output. So many people can listen to the same broadcast at any one time.
The New Jersey company VocalTec also provides software for putting audio on the Internet. Known as Internet Wave, or I-Wave, it too compresses the sound data to work within the limitations of TCP. Unlike Xing, however, VocalTec has developed its own compression software to do the job.
So far, most audio transmissions sent over the Internet have been speech based. But as 28 800 bps modems become affordable and widespread, music on the Internet will become a realistic option. The newest versions of both RealAudio and I-Wave support this speed, providing sound quality comparable to monophonic FM broadcasts.
Medium tuning
Internet broadcasting is unlikely to rival radio for the conceivable future, but that doesn鈥檛 mean it is a waste of time. Turning radio programs into data files alters the nature of the medium. 鈥淩ight now, radio is topical, of the moment,鈥� says Jay Allison, an independent producer of programmes for National Public Radio and other US outlets. But once they have been put on the Net, sound broadcasts can be archived, indexed, searched and retrieved. Today鈥檚 radio programme is ephemeral: something that is heard once then gone forever. Making radio archives changes the state of the art completely, says Allison.
WRN is putting this new found capability to use in its audio-on-demand service, which allows people to catch up on programmes that they missed when they were broadcast live. WRN captures news bulletins from stations such as Channel Africa and Voice of Russia, and stores them on its Web site as RealAudio files. Most remain available for downloading for the following 24 hours.
Of course, audio is only one piece in the Internet jigsaw. Fused with text and graphics, it provides something that is not quite a radio programme and not quite a magazine but a little of both. For instance, the Web-based Thailand Digital Magazine now includes RealAudio files of current pop hits from Thailand. And HalluciNet, a Web site from the Los Angeles club scene, is using RealAudio to broadcast a soap opera.
Charging people to listen to programmes could be next on the agenda. Martin Dunsmuir, general manager of Progressive Networks, says the RealAudio protocol includes the ability to include pay-per-listen information, which will make it possible for broadcasters to create subscription services. Much like the Cerberus digital jukebox that lets customers pay to download songs, these new services will let customers pay to listen to programming.
Eventually, radio networks might broadcast programmes over the air for free, while charging customers to browse through their archives. But Cohen points out that the lack of any established law covering broadcasting on the Net means that issues such as charging, copyright and contracts are still problematical.
Despite these uncertainties, Dunsmuir remains a firm believer in Internet audio broadcasting. He compares the current state of Internet broadcasting to the early days of FM radio in the 1950s. Soon, he says, 鈥渁ll radio stations will have an online component鈥�. And that will allow every programme to be archived, cross-referenced and retrieved. A revolution in radio is on the way 鈥� but probably not the end of broadcasting as we know it. Even Dunsmuir admits: 鈥淯ntil you can listen to the Internet in your car, there鈥檚 going to be radio.鈥�