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Real Media Streaming
pg. 20

• Methods For Streaming Real Media Files
• Streaming Real Media through HTTP
• Streaming Real Media with RealAudio Basic Server

RealAudio® and RealVideo®, developed by Real Networks, Inc., are among the most popular methods of broadcasting audio and video content across the Internet.
Collectively known as Real Media, RealAudio and RealVideo use a technology called streaming. Rather than force you to download an entire media file to your computer before you can play it, this technology allows your virtual server to play RealAudio and RealVideo clips over the Internet while they are being downloaded to your computer.

Methods For Streaming Real Media Files
All virtual server products support http streaming of Real Media files. All customers can optionally use the RealAudio Basic Server, which provides more efficient media streaming than the http protocol and provides a Web-based administrative interface to the streaming software. Both http streaming and RealAudio Basic Server streaming are described in the following sections.

Streaming Real Media through HTTP
Your virtual server can stream RealAudio and RealVideo files through the http protocol. While this method is not as robust as using the fully-featured RealAudio Basic Server, it does provide a reasonable method for streaming RealAudio and RealVideo content. Before you can stream media files through http, however, you need to modify the file on your virtual server that defines file types. This file is called mime.types and is located in your ~/www/conf directory.
To enable Real Media file streaming, open a SSH session to your virtual server and type the following at the command prompt:
cd www/conf Enter
pico mime.types Enter
The above commands open your ~/www/conf/mime.types file within the pico online editor. Using the editor, verify that the following lines appear somewhere in this file. If the lines are not there, you will need to add them:
audio/x-pn-realaudio         ra ram rm
audio/x-pn-realaudio-plugin    rpm
Once you’ve verified that these lines are present, or have been added if necessary, exit the editor. Your virtual server will now be able to stream RealAudio and RealVideo files.
You can now upload Real Media files, which have either an .rm or .ra file extension, through FTP. Be sure to upload Real Media files in binary mode, and to place them somewhere within or below your virtual server's ~/www/htdocs directory.
With your media file in place, the next step is to create a Meta file. A Meta file is a file that points to another file. This file is the key to properly streaming Real Media files. Real Media Meta files are simply text files with a .ram extension that contain the location of your actual Real Media file. To play a Real Media file on your computer, you point your Web browser to this Meta file. The RealPlayer program then access the actual media file and plays it while it streams.
Here’s an example. Suppose you have a RealAudio file called myrafile.ra, which has been uploaded into the ~/www/htdocs directory of your virtual server. Assuming the .ra and .ram file types are properly defined in your virtual server's ~/www/conf/mime.types file as described above, you would need to type the following from your command prompt to create the Real Media Meta file:
cd ~/www/htdocs Enter
pico myrafile.ram Enter
This opens a blank file called myrafile.ram in the pico editor. While in the editor, type the following to point this Meta file to the actual Real Media file (replace yourdomain.com with the domain name or IP address of your virtual server):
http://www.yourdomain.com/sound/myrafile.ra
Press Enter a couple of times to ensure that there is a hard return at the end of the file; then press Ctrl+X, Y, Enter to exit the editor and save the changes.
If everything has been done correctly, and you have RealPlayer installed properly on your computer, you should be able to listen to this RealAudio file by pointing your Web browser to the following URL:
http://www.yourdomain.com/myrafile.ram
If you want to link to this file from a Web page, the following HTML source could be inserted into the Web page:
<A HREF="http://www.yourdomain.com/myrafile.ram">
Click here to listen!</A>

Streaming Real Media with RealAudio Basic Server
On your virtual server you can stream RealAudio files using the RealAudio Basic Server software from RealNetworks. The Basic Server software provides more efficient media streaming than the http protocol, and provides a nice Web-based administrative interface to the streaming software.
To install the Basic Server software, either Telnet to your virtual server and type:
vinstall realaudio
At the command prompt, or select it from the Available Packages menu of the VAdmin Suite Software Manager. You'll be asked to provide a password to secure the Basic Server administrative interface. The install procedure will create a ~/usr/local/pnserver directory.
You will need to start the server by typing the following commands from a Telnet session:
cd ~/usr/local/pnserver/bin/ Enter
./pnserver ../server.cfg Enter
To stream RealAudio files using the Basic Server software, you should place them in your ~/usr/local/pnserver/content directory. You can then access them through a Web browser with a URL like this:
http://www.yourdomain.com:7070/ramgen/filename.ra
Be sure to replace yourdomain.com with your actual domain name and filename with the actual name of your audio file. The :7070 is necessary to open the Real Server port.
To administer your Basic Server software through the Web, point your browser to http://yourdomain.com:7070. When asked to provide a username and password, leave the username blank and use the password that you provided when you installed the RealAudio package.

For more information about how to create .ra and .rm files to use on your Web site, or about any of the RealNetworks products, please visit the RealNetworks Web site.