Synchronizing Shared and Wrapper Playlists
The syncEvent attribute sends a playlist synchronization event from the shared playlist on a broadcast publishing point to a client wrapper playlist. This attribute applies only to a broadcast publishing point.
You can use the syncEvent attribute to play a local advertisement from an ad server. For example, assume that an end user connects to a content provider and requests a Web page. The Web page contains a URL to a broadcast publishing point on the Windows Media server of a content distributor. When the user clicks the URL and connects to the content distributor, the shared playlist on the publishing point plays a movie clip and sends an event notice to the wrapper playlist. The following example illustrates the shared playlist.
<?wsx version="1.0"?>
<smil>
<media src = "c:\wmpub\wmroot\Clip_1.wmv" syncEvent = "LocalAd" />
</smil>
The wrapper playlist contains references to the content requested by the client and to an ASP page on an ad server.
<?wsx version="1.0"?>
<smil>
<excl>
<priorityClass peers="pause" >
<media id="WrapperMedia1" src="%RequestedURL%" begin="0" />
<media id="WrapperMedia2" src="httpd://server/LocalAd.asp"
begin= "LocalAd.begin" dur="30s" />
</priorityClass>
</excl>
</smil>
The ad server can use the name of the playlist requested by the content distributor to create a playlist that contains targeted advertisements. The ad server downloads the playlist to the content provider, and the local ads referenced in the playlist are streamed to the end user. When all of the media elements in the downloaded playlist have been streamed, the content distributor begins playing the content requested by the client. For more information about downloading playlists, see Downloading a Playlist from a Web Server.