An announcement file is a Windows Media metafile with an .asx file name extension that is used to redirect clients to content on your Windows Media server. Announcement files can be distributed to clients from a Web site, sent as an e-mail attachment, or shared on network drive. By default, the announcement file is associated with Windows Media Player. The announcement file uses Extensible Markup Language (XML) syntax and can contain additional information to be displayed in the Player, such as file properties and captioning information. The announcement file can also contain additional instructions for the Player, such as instructions to open a Web page or to send logging data to a server.
In the Windows Media Services snap-in, you can create announcement files by using the Unicast Announcement Wizard. If you are using multicast transmission, you can create an announcement file when you create a multicast information file by using the Multicast Announcement Wizard.