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4/8/2010

This interface abstracts an object that has typed input and output connections and can be aggregated dynamically.

All DirectShow filters expose this interface.

Because the IBaseFilterinterface derives from the IMediaFilterinterface, it inherits IPersist.

When to Implement

Implement this interface on every DirectShow filter. It is recommended that you use the CBaseFilterclass library to implement this interface.

When to Use

The filter graph manager is the primary user of this interface.

Applications or other filters can use IBaseFiltermethods directly to enumerate or retrieve pins or to get vendor information, but should not use any methods derived from IMediaFilterto control media streaming (use the IMediaControlmethods on the filter graph manager instead).

Methods in Vtable Order

The following tables show the methods that appear in the Vtable beneath the standard COM methods inherited from IUnknown.

IMediaFilter method Description

Stop

Informs the filter to transition to the new (stopped) state.

Pause

Informs the filter to transition to the new (paused) state.

Run

Informs the filter to transition to the new (running) state.

GetState

Determines the state of the filter.

SetSyncSource

Identifies the reference clock to which the filter should synchronize activity.

GetSyncSource

Retrieves the current reference clock (or NULL if there is no clock).

Passes a time value to synchronize independent streams.

IBaseFilter method Description

EnumPins

Enumerates the specified pins available on this filter.

FindPin

Retrieves a pointer to the pin with the specified identifier.

QueryFilterInfo

Retrieves information about the specified filter.

JoinFilterGraph

Notifies a filter that it has joined a filter graph.

QueryVendorInfo

Retrieves optional information supplied by a vendor for the specified filter.

Requirements

Windows Embedded CE Windows CE 2.12 and later
Windows Mobile Windows Mobile Version 5.0 and later
Note Microsoft DirectShow applications and DirectShow filters have different include file and Library requirements
For more information, see Setting Up the Build Environment