Microsoft Unified Tuning Model Interfaces

These interfaces are used primarily by (1) the Guide Store Loader to create tune requests for storage in the Guide Store, and (2) programs that install custom tuning spaces on a system. Applications use these interfaces in the following scenarios to:

• Create or modify a tune request dynamically.
• Test the validity of a tuning space.
• Create a default preferred components list that indicates user preferences for options such as the audio stream language.
• Examine the components (such as audio substreams) available on a specified service.

For more information, see The Microsoft Unified Tuning Model.

Tuning Space Interfaces

These interfaces manage tuning space objects. You will never use the base class ITuningSpace interface directly; you will always use a derived interface that is specific to a particular network type.

Tune Request Interfaces

Tune requests are not co-created directly. They are obtained through a call to CreateTuneRequest on a network-specific tuning space interface, such as IDVBTuningSpace. The base class ITuneRequest interface is never used directly; its methods are only used through the derived interfaces.

Stream Component Interfaces

A "component" in this context refers to a substream within a broadcast. Applications create a default preferred components collection based on user input, in order to specify, for example, a preferred audio stream language. When an audio stream is specified in this way, the Network Provider will always attempt to use it for all tune request in the tuning space (See ITuningSpace::put_DefaultPreferredComponentTypes.) In some cases the actual components of a broadcast stream can only be discovered after reception begins, or the actual components may differ from what was advertised in the EPG information. At that time the BDA Network Provider will fill in the Component information in the tune request, and the application can then retrieve it and use it, for example, to change the audio stream or determine which audio streams are currently available.

Locator Interfaces

Locators are used by the Network Provider and other filters in the graph to determine how to locate a specified program. These interfaces are not used by applications except possibly for debugging purposes. Third parties that install new tuning spaces should also provide a default locator for the tuning space. An individual tune request contains a locator, which can be different from the default locator. If present, the locator in the tune request takes precedence over the default locator