The page was initially written some years ago when the main focus was RealAudio and Netscape browsers and their behaviour. It has since been updated to talk about MP3 streaming. However, with newer browsers things stream automatically when you click an audio file anyway, making this tutotial partially obsolete

When do you need a server? Well, with a RealAudio server, you can do many things that you can't with this approach:

• Scalability up to many many many listeners
• Using UDP packets and multicasting
• Paced packet transmission (the data is sent in the audio rate, not in the servers as-fast-as-it-can rate)
• Live audio
• Jump back or forth in the recording (fast fwd, rewind).

But for us small-time users, the standard http-server is sufficient. And that is what this document will talk about.

And this is the same, if you use a compressed RealAudio or MP3 file. Only it's click . . . wait . . . "hello there" instead! Only the wait is shorter (beacuse the file is shorter!)

What we want is streaming audio - the file should be heard as it is being downloaded. This is something RealAudio has always been very good at - but before version 3.0, this required special server software!

First of all, you must get some audio to compress. Sample it with your soundcard into a .WAV file. Use the RealProducer or your favourite MP3 encoder to compress it to a .ra or .mp3 file.

• We will be working with an example file named melody.wav, which is 1 minute long, 44.1khz, 16 bit, mono. That's a 5.3 megabyte file

The RealProducer has several different options on how to encode the files, and to what bandwidth. In this first example, just encode it as a "28.8 mono, full response". Let's name the output file melody.ra, which is a 120k file (1/44:th the size). Or we can encode it as an mp3 with your favourite tool and call it melody.mp3

   <a href="melody.ra">Click to hear my melody!</a>

or

   <a href="melody.mp3">Click to hear my melody!</a>

Sure, this would work, but we would have gained little; when the user clicks the link, the browser (e.g. Netscape Navigator) first downloads the entire 200k file, and only after this launches the helper application (in this case, the RealAudio player).

Okay, we only had to wait for 200k instead of 5.3megs, but it wasn't streaming!!

So how do we solve it? The answer is with a stub file!

With RealAudio, the stub files have the extension .ram (There's also .rpm for the plugin variant, which works the same way, but is beyond the scope of this document) and for MP3 files it's called .m3u

What you do, is that you create a simple textfile in your favourite text editor. In Windows, Notepad is the ideal choice. This simple text file should contain only one line of text, namely, the full URL of the actual sound (.ra or .mp3) file!

So, create a file called melody.ram or melody.m3u that contains the following:

   http://www.your.server.com/~your/directory/melody.ra

or

   http://www.your.server.com/~your/directory/melody.mp3

Now change your HTML page to read:

   <a href="melody.ram">Click to hear my melody!</a>

or

   <a href="melody.m3u">Click to hear my melody!</a>

Please note the use of .ram / .m3u instead of .ra / .mp3.

• When the user clicks the link, the browser (Netscape) downloads the entire file, as usual. But in this case, it's just the melody.ram/.m3u file - which is just a few bytes and downloads lightning fast.

• Next, the browser launches the helper application, and hands it the file.

• The helper application (The RealAudio or MP3 player) gets the file. It detects (by looking in it) that this isn't an actual audio file, but a stub file.

• The player then by itself opens a Network Connection, and starts downloading the actual melody.ra/.mp3 file, and playing it as it is being downloaded! This downloading across-the-net is done completely by the player, and does not go through the browser (Netscape) at all.

This method, with variations, is used by almost all the network products that use streaming;

• A stub file is used in place of the real file.
• The HTML page links to the stubfile.
• The stubfile is handed to the helper.
• The helper parses the stubfile, and gets (and plays) the actual file

1. Get your server set up with the right mime types
2. Compress some audio (i.e. create the file(s) with .ra or .mp3 extension)
3. For each .ra or .mp3 file, create a stub file with a text editor.
4. The stub file contains just one line of text; The complete URL of the actual .ra or .mp3 file
5. In your HTML file, link to the stub file (the .ram or .m3u, not the .ra or .mp3!!)
6. Done!

• The Netscape "about:" trick

  To check mime-types of things, use the Netscape "about:" URL feature, i.e. type into the URL something like:

  about:http://www.foo.com/myfile/myfile.ram

  If the type comes out as "Unknown", just type the adress only once (without "about:") and let Netscape load it, then try the "about:" trick again.

• Use your Players 'Open Location' as a test device

  Before you even make the .ram stub file, test that your adress is actually working by using "Open Location..." on the your players "File" menu. When it works in Open Location, then copy that exact text into your .ram or .m3u file. Remember, upper/lower case is important!!

• The infamous Geocities Stub File problem

  I've been asked this so often, that I've given it a special section in the file :-)

  Geocities is a free web page provider. Adresses on Geocities has a certain form, i.e. something like http://www.geocities.com/HollywoodHills/Garage/1234. However, since many users forget to write the uppercase characters in "HollywoodHills" and write "hollywoodhills", although in reality the paths are case-sensitive, Geocities has implemented a feature where it redirects the URL to the correct, upper-case variant. That has led most Geocities people to believe case is not significant. IT IS!. "HollywoodHills" is not the same as "hollywoodhills".

  To make this worse, the RealPlayer does not support redirection! So it gives a cryptic error, instead of playing the audio.

  The fix is simple - provide the exact and correct path in the .ram stub file - with the correct case. Use the Open Location trick mentioned above to test, and you will get nice streaming RealAudio on Geocities too!

Good luck!

Several versions for different bandwidths

The easiest way is to simply provide several versions of your song. If you purchase RealAudio Server all this is handled automatically. But when you are using a standard WWW-server, you will have to do this "manually", by adding several entries to your HTML code.

To make the largest possible population happy, you should do the following:

• Provide a 28.8 version of the file, streaming (i.e. using a .ram file as described above), to cater for the modem user

• Provide a 64kbit (ISDN) and/or 128kbit (Dual ISDN) version(s) of your file, streaming (i.e. using the .ram file), to cater for the lucky few with high bandwidht access!

• Provide a 64kbit and/or 128kbit version(s) of your file, non streaming (i.e. not using the .ram file). This allows a audiophilic modem user to download the .ra file to his local harddisk, and play it from there. This way, he can hear the music in full fidelity without having the available bandwidth.

• Provide a 28.8 RealAudio 2.0-compatible, non-streaming file, for the poor souls with RealAudio 2.0.

• Compress one file with a 28.8 compression. Call it melody0.ra.
• Write the accompanying stub (melody0.ram) file.
• Compress another file with a 64k (ISDN) compression. Call it melody1.ra.
• Write the accompanying stub (melody1.ram) file.
• Compress one file with a 128k (Dual ISDN) compression. Call it melody2.ra.
• Write the accompanying stub (melody2.ram) file.

(The convention to name the files 0, 1 and 2 is just the way I do it. If you want to call the files melody_28.ra, melody_64.ra and melody_128.ra, or chocolate.ra, vanilla.ra and strawberry.ra, that's your choice)

Now write HTML similar to this:

   <B>My cool song "...."</B> Hear it with RealAudio (3.0 or newer)
   <UL>
   <LI> In 28.8 <a href="melody0.ram">streaming</a>/<a href="melody0.ra">download</a>
   <LI> In 64k <a href="melody1.ram">streaming</a>/<a href="melody1.ra">download</a>
   <LI> In 128k <a href="melody2.ram">streaming</a>/<a href="melody2.ra">download</a>
   </UL>

Which will look like this (using one of my songs, "Dream State" as example file):

Technical details

• Real Networks (fathers of RealAudio) homepage
• The RealAudio Tech support pages (some neat tricks and tips)

Bye now. Surf safely.