Tuning Model Objects

Microsoft DirectShow 9.0

Tuning Model Objects

Tuning Space Objects

A tuning space represents a particular type of network, along with other information that identifies a particular network provider or broadcast source. Microsoft provides five default tuning spaces; third parties may add their own tuning space. Tuning spaces are stored in the system registry. Use the SystemTuningSpaces object to create new tuning spaces or access existing ones.

Object Description
AnalogRadioTuningSpace Represents a tuning space for analog radio networks.
AnalogTVTuningSpace Represents a tuning space for analog TV networks.
ATSCTuningSpace Represents a tuning space for ATSC networks.
AuxInTuningSpace Represents a video auxiliary input, such as S-Video or composite video.
DVBSTuningSpace Represents a tuning space for DVB-S networks.
DVBTuningSpace Represents a tuning space for DVB networks.
SystemTuningSpaces Represents the collection of tuning spaces installed on the host system.

Stream Component Objects

In digital television, a component refers to an elementary stream within an MPEG-2 program stream. For example, a program stream may have three audio components, one in English, one in Spanish, and one in French. In some cases, the components that a service provides must be discovered after reception begins. The Transport Information Filter (TIF) works with the Network Provider to fill in the component data in the tune request after tuning has occurred. The application can then examine the tune request, for example to inform the user of additional audio streams that are available.

Object Description
ATSCComponentType Represents an ATSC component type.
Component Represents a generic program component.
Components Represents a collection of components.
ComponentType Represents a generic component type.
ComponentTypes Represents a collection of component types.
LanguageComponentType Represents a component type that has a defined language code.
MPEG2Component Represents an MPEG-2 stream component.
MPEG2ComponentType Represents a component type associated  with an MPEG-2 stream component.

Locator Objects

Locator objects contain low-level information that a tuner and Network Provider use to locate a program within a tuning space. This information includes the frequency and modulation type of the television signal, Quadrature Phase Shift Keying (QPSK) symbol rate, the type of forward error correction used, and other parameters specific to the network type. Each tune request contains a locator object, although it is not always necessary that all properties of the locator be set. A third party such as a cable or satellite provider may provide a default locator for their tuning space, which a Guide Store loader can use when creating tune requests. Locators are typically not used by applications, except perhaps for debugging purposes, or in the case where an application creates its own tune request.

Object Description
ATSCLocator Contains tuning information specific to ATSC networks.
DVBCLocator Contains tuning information specific to  DVB-C networks.
DVBSLocator Contains tuning information specific to DVB-S networks.
DVBTLocator Contains tuning information specific to  DVB-T networks.
Locator Base class for the other locators. Contains tuning information required for all network types.

Tune Request Objects

Tune request objects contains the information needed to tune to a channel within a particular network type. To create a tune request, call ITuningSpace::CreateTuneRequest on the tuning space for that network type.

Object Description
ATSCChannelTuneRequest Tune request for ATSC networks.
DigitalCableTuneRequest Tune request for digital cable.
DVBTuneRequest Tune request for DVB networks.
MPEG2TuneRequest Tune request for MPEG-2 transport streams.

See Also