How to Use RealAudio.

by Stephen Wilson


What is RealAudio

RealAudio is a technology for streaming audio over the web developed by Progressive Networks.  Streaming means that the audio starts to play as soon as it starts to arrive at the browser's computer instead of waiting for the whole file to load.  The technology also has the capability to broadcast live performance. It accomplishes these feats by using a very efficient compressor for audio files.

What do You Need to Offer RealAudio?

RealAudio is a proprietory technology.  To offer RealAudio on your site you must convert sound files into the special RealAudio format.  For best results you also should use the special RealAudio server that is optimized for sending out streamed RealAudio over the web.  RealAudio sells professional RealAudio encoders and Web servers.

They also free versions that do not have as many of the features. They provide a free download of an encoder. Also, some sound editing software for PCs and Macs has the abiilty to create RealAudio files. Also, you can arrange for your regular hthpd web server to send out RealAudio files.  It probably won't do as good of a job but this method does not require purchase of a special server.

Users will need to download a special plug in for their browser in order to receive RealAudio but the plug in is widely distributed.

What are the Steps to Creation of RealAudio and Sending it from Your Web Site?

1. Create a sound file in standard format.

2. Encode the file into the special RealAudio format.  You will need a special encoder from RealAudio or one of the sound editing programs that can produce RealAudio format as one of its opitons. These sound editors can output RealAudio files: Macromedia Sound Edit 16 (Macintosh), Sonic Foundry Sound Forge, and Syntrillium CoolEdit. You will need to make decisions about the nature of the encoding based on quality and anticipated connection of your web visitors. (see Real Audio documentation).  Make sure your files end with the right suffix.

3 A   (If you are using RealAudio's special server) Create a meta-file on your web server that points to the file on the special server.(see Real Audio documentation)  Upload your RealAudio sound file to the server.

or

3B (If you are using your regular httpd web server)  Upload your real audio file to your server.  Make sure the server is configured for the right MIME to send out RealAudio files.  Internet software needs MIME indications so that it will treat the data files in the correct way.  If you don't have access to the server configuration, you will need to ask your provider to add the configuration lines to their MIME list.  It is not a big deal - just a few lines of text, but it must be done.  Here are the lines.

audio/x-pn-realaudio (files with a .ra or .ram file extension)

audio/x-pn-realaudio-plugin (files with a .rpm file extension)

4  Creating a metafile:  You have to create a simple text file that points to your RealAudio file(s) that you want played when the user accesses the link pointing at the metafile.

 

5. Making sure visitors are set up.  You should warn visitors that they will need the RealAudio player or plug in to hear your sounds.  They also might have to configure their browser MIME to recognize the ram and rpm extensions.

6. Automatic playing within a page:  RealAudio supports both the Netscape EMBED tag and ActiveX for Microsoft Internet Explorer.  Below is a sample for Netscape plug in.  Notice the NOEMBED tag which allows users without plugins to access the stand alone player.  You can add many kinds of visible controls that will appear and arrange for autostart. See the RealAudio documentation for details of using these and IE instructions.

<EMBED SRC="samplemetafile.ram" WIDTH=300HEIGHT=134>

<NOEMBED><A HREF="sampleforplayer.ram">Use a stand-along player to play the file /A></NOEMBED>

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Hear is the RealAudio Documentation Site

- This page created by Stephen Wilson, Professor Conceptual Design, SFSU (http://userwww.sfsu.edu/~swilson) swilson@sfsu.edu
- More information about the Conceptual Design program is available at (http://userwww.sfsu.edu/~infoarts)
- It is a resource used in Art511 Art&Telecommunications course (http://userwww.sfsu.edu/~infoarts/Tele/Tele95.index.html)
- A comprehensive guide to Web design is available in the book World Wide Web Design Guide (Hayden Books) by Stephen Wilson
- The url of this page is (http://userwww.sfsu.edu/~infoarts/technical/sound/wilson.howtoliveaudio.html)