Introduction

Real Audio technology streams sound on the Internet straight from a Real Audio server to your computer without having to download the entire sound file. If you don't already have the Real Audio Player, go to the Real Audio Web Site and download it now. To get an idea of what Real Audio is and does, check out a couple of the links they provide, or look at the Triton project done last summer that features Real Audio: Descent in Monterey Submarine Canyon.

Encoding sounds for Real Audio can be extroardinarily complex and confusing. But, don't let that scare you off, because it doesn't have to be that way. Here, on this page, we are going to learn how to encode Real Audio files and how to link the sound files to your web pages. There will be links to further explanations that have been taken directly from the Real Audio web page - edited down to address only the Macintosh side of Real Audio (for you Windows people, visit the Real Audio Content Creation Guide).

Creating the original sounds, editing sounds/music, and recording sounds is not something we are going to be doing here. To do so would be an entire workshop in its self.We are only going to focus on actually encoding the Real Audio files. Real Audio provides a list of several sound editing applications that you can check out if you are interested.

Getting Ready to Encode

Encoding is the process of taking a sound file and converting it to the Real Audio format. You could compare this to changing a PICT image into a GIF or JPEG for use on the Internet. Real Audio supplies free encoders which can be downloaded at the Real Audio Encoder Web Site. If you don't have it already, go download it now.

The original sound files are called the Source files and they come in many different formats, just like graphics. The formats that the Real Audio Encoder supports include (for more a detailed look at formats, visit Source Files) :

• 8 or 16 bit mono or stereo files
• .snd, .sd2, .aiff, .au, .wav, .pcm

If your source file is not in one of the above formats, go into your sound editing program and convert it.

Encoding

OK, so you have installed the Real Audio Encoder onto your hard drive and have your source file ready to go. Let's start!

1. Open up the Real Audio Encoder by double clicking on the icon. The window below should appear.
   

    

2. You need to open the Source file to be encoded. Hit Input. An Open File dialogue box will appear. Find the file you will be encoding and hit Open. The file name will appear in the box next to the Input button. In the top portion of the interface, you will see that the Sampling Rate, Duration, Size, and Compressed boxes will now be filled out. These figures represent specific information about the sound.
   
   We are using a short clip of Captain Picard from Star Trek saying "Engage," it is only 1.1 seconds long. In the original .au format it was 9.0 K, once we encode it, that number drops down to 2.1 K.
   

    

3. The bottom half of the interface includes the Title, Author, Copyright, and Encoder. The first three are up to you to complete. This information will be shown when the Real Audio Player to anyone listening to the sound clip.
   
   The last part is where you tell RA Encoder what specific RA format you want. RA 28.8 is designed for modems that are 28.8 bps and up, T1 lines, and ISDN lines. RA 14.4 is designed for lower end modems and connections. Your selection will depend upon your connection to the Internet.
   
   
4. Once the information boxes are completed, hit Process. A Save dialogue box will appear (Shown below). Notice the ".ra" at the end of file name. This will be automatically placed there, you may change the name, but be sure to keep the ".ra". Hit save when you have named it.
   
5. Once the file is saved, try it out by double clicking on it (you must already have Real Audio Player installed).

Creating the Metafile File

When you are creating your web pages with Real Audio, you have to create a metafile. A metafile is a separate file that points the web browser (Netscape, Explorer, etc.) to the Real Audio Server. The server then sends the Real Audio file to your computer. The metafile is a one line text file that contains the URL of the file and it ends with ".ram". To see more about metafiles and how the Real Audio connection is made, visit the RA Details and Overview pages.

An Example

1. If you want to use the "engage.ra" file that we just created, you would first post the ".ra" file on the Real Audio Server (we will call the server http://www.server1.edu). (Note: The RA files will not be in the same folder, or probably even on the same server, as your web pages)
   
   
2. First, we would create the metafile. Open SimpleText or TeachText.
   
   
3. Type in SimpleText or TeachText:
   pnm://www.server1.edu/engage.ra
4. Save the text file as "engage.ram" - the ".ram" designates the file as a Real Audio metafile. This file can either go into the same folder as your web page, or in a folder of its own.
   
   
5. Go to your main web page, and create a link to the ".ram" file.
   
   
6. View document in your browser and try it out!

Exercise

1. Use the provided sound file and encode it in the Real Audio 28.8 format.
2. Create a metafile, assuming the Real Audio server is http://www.sdcs.k12.ca.us
3. Add a link to the metafile in a simple web page.

Using the Real Audio Server

If you are indeed interested in utilizing Real Audio technology for your web site, create the pages and then contact Josh Rude at the Dana Center about posting your RA files to the Triton Real Audio Server.

So you want to learn more...

Linked below is an abridged version of the Real Audio Content Creation Guide. It has been sectioned and edited for just Real Audio (Real Video is similar technology using Video) on the Macintosh platform. There are Windows and Unix explanations available at the Real Audio web site. Here are the links by subject:

• A More Detailed Overview
• Components of a RealAudio System
• RealAudio Files and Metafiles
• Source Files
• Encoder
• More on Metafiles
• Delivering a RealAudio Clip
• Preferences
• Editing RA files

Conclusion

Real Audio technology gives us a hint of the spectacular things to come with the Internet. It breaks down the barriers that have in the past made using sound online sluggish. The Triton Project has been lucky enough to acquire a Real Audio server to make utilizing this technology a reality.