Enhancement Stream

[This is preliminary documentation and subject to change.]

The enhancement stream is a script that synchronizes enhancement events with specific times during the interactive show. An enhancement event causes an action to be performed by the broadcast client. The client's response to an enhancement event are actions such as receiving a file transmission, updating program data, or displaying new enhancement content to the user.

For example, an enhancement announcement might send data about a future interactive show to the client. Controls on the client handle the announcement event and update the show listing in the Guide database.

There are three types of enhancement events currently defined:

• Enhancement announcements, which transmit information about an upcoming interactive show.
• FTS transmissions, which use the File Transfer Service (FTS) protocol to download enhancement files and dependencies to the client.
• Triggers, which command the client to perform predefined actions. For example, one type of trigger causes WebTV for Windows to display a new enhancement page.

When an enhancement stream is saved to a file, the enhancement events that the stream contains are stored as stream compiler statements. To locate more information on the stream compiler language, see Further Information on Data Services for the Client.