| Platform SDK: Broadcast Architecture |
The Advanced Television Enhancement Forum (ATVEF) is a consortium of industry leaders, including Microsoft Corporation, who are working together to produce a common, worldwide specification for the content format and delivery mechanisms of television enhancements. Based largely on existing Web standards (including HTML 4.0, ECMAScript, SAP/SDP, UHTTP, and DOM 0), the ATVEF specification is designed to provide a single solution for a wide variety of networks. It should be noted that, as far as the head end is concerned, ATVEF defines only the ways in which data is delivered. It is possible to send any type of content data whatsoever under ATVEF, although ATVEF-compliant clients are required to support only certain specific file types.
As an aid to content server application developers who wish to begin writing to the ATVEF specification, Microsoft is introducing a COM component, ATVEFSnd.dll, that wraps many of the ATVEF transport and formatting details. This component provides all the functionality an application needs to deliver ATVEF-compliant enhanced television programming. It is flexible, robust, and easy to implement. It is not, however, intended as a comprehensive solution for all broadcasting needs, and does not currently provide a complete implementation of the ATVEF specification. Most importantly, the component currently supports only Transport Type B as defined in the specification. It does not conveniently support simultaneous broadcasting on disparate network types, such as sending triggers through the vertical blanking interval (VBI) and content data by means of the Internet. The component is designed to send all announcements, packages, and triggers out over the VBI, or else by native multicast directly to a computer network.
As of the current writing, the ATVEF foundation specification is still in draft form; however, the current version, 1.1 r26, is the version on which the final license and compliance statements have been based, and the document is in the final phases of approval by the fourteen Founder companies. For additional information, visit the ATVEF Web site at http://www.atvef.com.