| Microsoft DirectX 8.1 (C++) |
This topic applies to Windows XP Home Edition and Windows XP Professional only.
The Guide Store can group channels into a collection called a channel lineup. The client application can use, or create, ChannelLineup objects to provide the user with a subset of all the available channels. For example, the client application could work with a sports channel lineup or a movie channel lineup.
The notion of a "sports" or "news" channel lineup requires tagging service objects with these characteristics. The Guide Store uses a MetaPropertyType object for this purpose. There would be a "sports" MetaPropertyType object and a "news" MetaPropertyType object. Simply attaching these objects to a Service object would tag that Service object with these metaproperty types.
Most broadcast sites contain more than one type of content. A sports station might interrupt occasionally for the news. While the news is on, the station is a "news" station. Otherwise, it is a "sports" station. The MetaPropertyType objects do not identify the "sports-ness" or the "news-ness" of the station. Accordingly, the Guide Store does not attach these MetaPropertyType objects directly to the Service object that represents the station. Instead, it attaches a MetaProperty object. This MetaProperty object contains one MetaPropertyType object plus a value. For example, attaching a MetaProperty object to a service object where the MetaProperty object has a value of 0.8 and an attached MetaPropertyType object for "sports" would indicate the service object is 80 percent sports. Similarly, a second MetaProperty object with a value of 0.2 and a MetaPropertyType of "news" could be attached to the Service object to indicate that the service is 20 percent news.
For information on the objects discussed in this topic, see the following:
C++
Visual Basic