Online radio stations are giving their real-world counterparts some serious competition.

A long time ago, in a galaxy far, far away, some bright spark invented a device capable of grabbing signals from the ether and unscrambling them into sounds recognizable to the human ear. The invention was, of course, radio and it represented a pivotal moment in the science of wireless communication, with significant military and non-military applications.

Segue gently into the present...

Sometime in early 1994, a small SillyCon Valley startup named RealNetworks [ http://www.real.com ] embarked on an ambitious project to broadcast audio live over the Internet - in effect, to set up an online radio station, which anyone with a suitable player could access! So, for this week's report, we thought we'd tell you a little bit about the RealAudio or streaming audio technology used to achieve this feat. And after giving you the skinny on what you need to set up your very own online broadcast, we'll direct you to the very best sites for live music, news and reviews!

Before we begin, we need to tell you that RealNetworks isn't the only one with a streaming audio/video package. Vivo [ http://www.vivo.com ], Microsoft [ http://www.microsoft.com/netshow ] and Macromedia [ http://www.macromedia.com ] have their own competing systems. However, a discussion of all these architectures is well beyond the scope of this ezine; so we're going to concentrate all our attention on RealAudio, since it is the most well-known of the lot!

One of the most important reasons streaming technology is so cool is that, before it came along, you had to download an entire sound file before you could begin playing it. This was made all the more annoying by the fact that you had no clue if what you were downloading was even worth listening to!

RealAudio, on the other hand, compresses a standard audio file and sends it as a "stream" of information to the listener over the Internet in real-time. The advantage: smaller audio files, faster transmission time and therefore a much shorter wait for the end-user. According to RealNetworks documentation, the compression algorithm used provides a compression ratio of 44 to 1 - quite impressive, we would think!

The RealAudio system consists of three basic components: a server, a client and an encoder. Let's take a closer look at each of these villains:

The server: As generally understood in the rarefied language of technocrats such as ourselves, a server is a system whose purpose is to "serve", or make available, data as and when requested by another system, popularly known as a "client". And, as we're sure you've guessed, a RealAudio server simply makes a RealAudio encoded sound file available to the client as and when requested.

However, a particular advantage with the RealAudio system is that any common Web server can serve RealAudio files; a special-purpose RealAudio server is not required, except in the case of live transmissions. And the reason this is such an advantage is that there are a large number of freely available Web servers which, with only minor modifications, can make a website RealAudio-capable.

The client: Now that we're done with the server, let's talk about the client. In this case, the client is the RealAudio player application, imaginatively called...yup, RealPlayer! This is the software which connects to the server and downloads, decompresses and plays back the sound file.

The encoder: The encoder is what is used to make the conversion from a standard .WAV or .AU file to the RealAudio (.RA ) file format. It is essentially a tool which takes in an uncompressed audio file as input and outputs a RealAudio encoded file, which is sent by the server to the client whenever the client requests it. In the case of live transmissions, the encoder will compress input from external input sources like a microphone in real-time.

And to round this up, an explanation of exactly what happens when you click a RealAudio link in your browser:

  1. User clicks link, which references a .RAM ( RealAudio Metafile ) file, essentially a text file which contains the location of the actual RealAudio ( .RA ) file.

  2. Assuming a properly-configured Web server and RealPlayer client, browser begins to download the file. Header information in the file identifies it as a RealAudio file, which in turn activates RealPlayer, which pops up and begins decoding and playing the file back through the output device, usually speakers.

  3. User immediately stops working, the better to hear the wonderful music coming his way. Productivity drops, the company shuts down and user finds himself out on the street selling matchboxes in the rain.

In order to assist interested users (and perhaps, garner itself some free publicity), RealNetworks has made available, on its website, free versions of its RealServer, RealPlayer and RealEncoder software. Although these lack some of the features found in the commercial versions, they are more than sufficient for experiments...and you can't beat the price!

There are just too many sites online carrying RealAudio content. So we thought that we would direct you to two of the Internet's best directories for this kind of content first, and then let you in on some of our favorite sites !

http://www.timecast.com http://www.broadcast.com

Timecast and Broadcast.com: Timecast is actually a service provided by RealNeworks - an online listing of all sites carrying streaming content, in different categories such as music, entertainment, sports, news, etc. And Broadcast.com is another site doing the same thing. Chances are, if you're looking for something specific, you'll find it on one of these two!

We can't live, work or play without music! So we hunted high and low for a site capable of meeting our stringent requirements...and we found two!

http://www.discjockey.com

Music from the 1940s through the 1990s, neatly categorized into different genres for each decade. Top 40 hitlists. Pre-recorded programs with a minimum of 30 minutes of fantastic music, and even a playlist. And if that isn't enough, two live transmissions - one for 80s music and the other for 90s music - 24 hours a day without interruption! And let's not forget it's USP, something no other site has to offer - the ability to dedicate a song to someone online and have your dedication appear on the screen of everyone tuned into the same channel!

http://www.rollingstone.com

Another cool site with loads of attitude, RSN has three live channels playing live pop, rock and new wave music. All broadcasts are live transmissions - no prerecorded stuff for these guys! And they even let you watch music videos of your favorite groups using RealVideo technology.

http://www.cnn.com

CNN provides hourly news reports, headline news, financial news and breaking stories in its live AudioSelect service. If you're a news junkie, this is the only site you need! Transmissions include both audio and video; however, there are no archives of past broadcasts available.

http://www.film.com

One of the most comprehensive online resources for movie news, Film.com provides audio reviews of the latest and upcoming movies, together with video clips, trailers and short films using a combination of RealAudio and RealVideo technologies.

http://www.ahn.com/livebirth/index1.htm http://play.rbn.com/?ahn/ahn/demand/sean1-45.rm http://play.rbn.com/?ahn/ahn/demand/lbpress_45.rm

And lastly, a few links to video of the first human birth to be broadcast live on the Net:

Till, next time...stay healthy!

This article was first published on 18 Sep 1998.