About the Online Training Sample

The Online Training Sample is run from Default.htm, which contains three frames: Asfpage.htm for holding the embedded Windows Media Player control, Slides.htm for holding the JPEG image files, and Toc.htm for holding the auto-generated table of contents links. The Training directory also holds the image files and the .asf file (Training_28.asf).

About the .asf File

Training_28.asf includes markers and script commands. Markers are assigned to points in the presentation where new topics begin. Script commands are assigned to points where the author wants slide changes. All script commands in this sample use the type string "URL", which instructs Windows Media Player to send a URL to the browser; the command string of the script command contains the actual URL. In the following example, the URL text points to an image, and indicates the frame into which it is placed.

URL slide1.jpg&&slides

About the Table of Contents

The table of contents is created dynamically by script in the Web page that reads the markers contained in the incoming ASF stream. The ability to read markers dynamically is very useful. If markers are hard-coded for a specific .asf file, the HTML scripting has to change every time the .asf file changes. By including HTML scripting that automatically generates a table of contents, the four .htm files included in this sample can play any .asf file. The only parameter that must be changed is the .asf file name.

The marker names in the table of contents are also links. When a marker name is clicked, scripting in the page causes Windows Media Player to seek to the named marker. For more information, see Scripting Reference in the Windows Media Player Control SDK.

Expanding on the Sample

The following examples show how you can expand on the Online Training Sample by modifying the HTML file included in this SDK.

Play back live. The Online Training Sample plays an .asf file, but there is no reason why the incoming content cannot be live. The same .htm files can point to an .asx file that plays a live presentation from a Windows Media Services multicast station. Script commands containing the location of the image files can be sent live using Windows Media Encoder or an application such as the Encoder Scripting Utility Sample in this SDK. You can also use the .asx file to populate Windows Media Player with display text, graphics, and links.
Archive a live event. Windows Media Encoder or Windows Media Services can be set up to create an .asf file concurrently with a live encoding session. This can be very useful for archiving live events. Immediately after a presentation, you can also make the .asf file available so users can replay it at their own pace. All slide-change cues are automatically included, because script commands that were sent during the live session are recorded in the .asf file. Markers can be added afterward by using Windows Media ASF Indexer or the command-line utility, ASFChop. For more information, see the Windows Media Tools Documentation.
Add DHTML. If Internet Explorer 4.01 or later is your primary browser, DHTML is also available to you. For more information about integrating ASF content and DHTML, see Dynamic HTML Sample.

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