HTTP streaming is an alternative approach to serving RealAudio and RealVideo files on the Web without the added management requirements and expense of a RealSystem G2 hosting account.
Although this techniques is not well-suited for high-volume sites serving numerous simultaneous streams, many smaller Web sites can benefit tremendously from this simple and inexpensive approach.
That's because it relies on HTTP (HyperText Transfer Protocol) which is already used by all Web servers to store and transmit ordinary text and graphics files on the Web. And from the producer's point of view, there's no
added effort because RealAudio and RealVideo files prepared for use on an HTTP server are identical to those used with a streaming media server.
There are some important differences however, between the capabilities of HTTP and specialized server software such as RealNetworks' RealServer 7.x.
For example, you can't automatically detect the user's modem speed using HTTP. Instead, files optimized for each of the various connection speeds must be made available for users to select themselves. Also, the HTTP-based approach does not allow for live streaming audio or video presentations because complete files must be stored on the Web server before they can be accessed.
Finally, HTTP does not make efficient use of server resources, and as a result doesn't perform well under heavy server loads.
But for sites serving no more than a handful of simultaneous streams at any given time, this is a great way to add streaming audio and video features to your Web site without incurring extra costs.
Here are instructions for preparing RealAudio or RealVideo files for use on the Web.
- Copy your encoded files (files with the .ra, .ram, .rm or .rpm extension) to your World Wide Web server.
- Use a text editor (such as Notepad or SimpleText) to create a metafile containing a URL to your file.
For example, the contents of your metafile should be in the following form:
- http://www.yourdomain.com/path
where path is to the location of your encoded file. Remember to separate directories with a / on the Unix platform.
- Save your metafile as a text using a .ram file extension.
- In your HTML document, reference the metafile in a hyperlink. For example:
- <A HREF="filename.ram">
- <A HREF="http://yourdomain.com/file.ram">
You can use relative or complete paths. If you use complete paths, you must include both the hostname and the complete path. For example:
- <A HREF="http://www.yourdomain.com/media/welcome.ram">
- When a user clicks on the link, the streaming file(s) begin to download. The RealPlayer begins playing after a few seconds; it does not need to wait for the entire file to be downloaded.
Stream from RealSystem G2 using Ramgen
This section provides examples that show how to set up streaming presentations from our RealSystem G2 server.
- Transfer the clip to the RealServer directory provided to you by SelectNet.
- Link your Web page to the clip with an HTML hyperlink that begins with
http://, and that specifies the RealServer address along with the ramgen parameter. This information will be provided to
you after you sign up for the account.
In your HTML source file, the link will look like the following example:
<a href="http://g2server.select.net:8080/ramgen/~mydir/myclip.rm"> Click here</a>
- In your Web browser, click the link to verify that it works. RealPlayer will launch as a helper application and, after a few seconds of buffering, will play the streaming clip.
Embedding a RealVideo Clip in a Web Page
Using RealPlayer's Netscape plug-in, you can embed a RealVideo clip directly in your Web page. The following procedure assumes that the video is 176 pixels wide by 132 pixels high. It places the video window and the full RealPlayer control panel in your Web page.
To embed the clip in your Web page:
- In your Web page, add the
<EMBED> tag with the RealVideo URL, window size, and ImageWindow control. The following example assumes that RealServer will stream the presentation:
<EMBED WIDTH=176 HEIGHT=132
SRC="http://g2server.select.net:8080/ramgen/~mydir/myclip.rm?embed"
CONTROLS=ImageWindow CONSOLE=one NOJAVA=true>
If you intend to play the clip back from a Web server, use an HTTP URL and link to a Ram file with the extension .rpm, as in the following example:
<EMBED WIDTH=176 HEIGHT=132
SRC="http://www.mydomain.com/media/myclip.rpm"
CONTROLS=ImageWindow CONSOLE=one NOJAVA=true>
- You can then add RealPlayer controls by inserting additional
<EMBED> tags that all use the same URL for the SRC parameter. The following example, which assumes that RealServer will stream the presentation, embeds the full RealPlayer control panel in the Web page, linking it to the image window through the same console:
<EMBED WIDTH=375 HEIGHT=100
SRC="http://g2server.select.net:8080/ramgen/~mydir/myclip.rm?embed"
CONTROLS=All CONSOLE=one NOJAVA=true>
As in the following example, use an <EMBED> tag when playing the clip back from a Web server:
<EMBED WIDTH=375 HEIGHT=100
SRC="http://www.yourdomain.com/media/myclip.rpm"
CONTROLS=All CONSOLE=one NOJAVA=true>
 |
Tip |
Because you can place each <EMBED> tag anywhere on
your Web page, you can use HTML to lay out the image
window and controls any way you want.
|
Transfer the clip to the appropriate RealServer or Web server directory. When streaming from RealServer, you are now ready to test the clip, because the Web page already contains the link to the RealVideo clip.
URL Reference
URLs to files and clips vary depending on what kind of file or clip you link to and what type of file contains the link. The following table provides a quick reference that shows which protocol is used for each of the various types of links. It also shows whether or not each link type should use RealServer's Ramgen utility.
Also Visit RealNetworks' Web Site
