[This is preliminary documentation and subject to change.]
On a broadcast client, all data including enhancements is received as a stream of digital data. From this incoming stream, the video and audio data are extracted and sent to one of two types of video control. Such video controls reside in the page displayed by WebTV for Windows or a World Wide Web browser. The two possible types of video control are Video controls and Enhancement Video controls.
At the same time video is received by its control, enhancements and triggers are received by an Enhancement control. An Enhancement control is an ActiveX control that responds to enhancement stream events. Like the video controls. the Enhancement control is hosted in an enhancement page displayed by WebTV for Windows or a World Wide Web browser.
The following illustration shows this process. Note that this diagram is simplified and does not display controls internal to Broadcast Architecture.
You can create enhancements that interact with Enhancement controls by embedding script or custom controls in the enhancement page. These Web applications can call methods of the Enhancement control and respond to the control's events. To locate more information about using the Enhancement control, see Further Information on Data Services for the Client.