In the early days, the best answer to this question would have been "not well." IMS listeners downloaded files via file transfer protocol and then played back the files. To say the files were large is an understatement. Newscientist reports "an hour of programming took up 30 megabytes-- enough to fill the hard discs of all but the most expensive workstations of that time--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--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."
The process needed more efficiency to attract larger audiences, and that's exactly what happened. Streaming technology was introduced and it has become the standard way for net listeners to pick up broadcasts. Streaming sends the broadcast/information to a user continuously. At the user end, a slight buffer delays the broadcast for a few seconds, to enable some error correction to occur, and the broadcast plays back as it streams to the listener/user.
Streaming does more than eliminate lengthy download times. It compensates for the relatively slow speeds of Internet connections. As PC News reported, "Your 28.8-kilobit-per-second (28.8-Kbps) modem has a throughput capacity of about 3.6 kilobytes (3.6K) per second, Approximately 1/40 the speed of the single-spin CD-ROM drive you junked last year. CD-quality audio requires about 176K of raw data per second, close to 50 times the capacity of your 28.8-Kbps modem." Due to this vast discrepancy, streaming uses a codec to compress the information as it's being sent and a codec to decompress the information after it is received, thus speeding up the transmission. However, as any Internet radio listener will agree, the process isn't perfect and there is a significant loss in sound quality.
From the user end, Internet radio reception is just a matter of downloading a (usually) free audio player. Several companies produce or had produced streaming equipment and players: VocalTec, Real Networks, Xing Technology Corp, Voxware and The DSP Group all produced products.
However, much like TCP/IP, Real Networks' RealPlayer has become the de facto industry standard. In a recent press release, Real Networks reported "over 26 million players have been downloaded from www.real.com since the company first pioneered the use of streaming audio with RealAudio." Perhaps the most telling of all statistics, Real Networks reports "the Hot Bot and Alta Vista search engines have identified that 19 out of every 20 Web sites that added multimedia chose RealAudio or RealVideo technology. (9/27/97-10/17/97)." In truth, Real Networks players have become so ubiquitous that downloading them is usually not even required. Both Netscape Communicator and Microsoft Internet Explorer come with the RealPlayer. Although Microsoft includes the RealPlayer with Internet Explorer 4.0, the company has also developed it's own audio/video player, offering Netshow 2.0.
The latest versions of the RealPlayer and Netshow 2.0 operate semi-independently from a web browser. To connect initially, a web browser is a convenient tool, but once the connection is established, the web browser can be closed and the players will continue to operate, allowing users to switch to any other desired task.
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