IKsTopologyInfo Interface
| Microsoft DirectShow 9.0 |
IKsTopologyInfo Interface
This topic applies to Windows XP Service Pack 2 and later.
The IKsTopologyInfo interface enumerates the nodes in a stream class driver. The KsProxy filter exposes this interface. Applications can use this interface to examine the internal topology of a kernel-mode filter.
In addition to the methods inherited from IUnknown, the IKsTopologyInfo interface exposes the following methods.
| Method | Description |
| CreateNodeInstance | Creates a COM object that represents a node in the filter. |
| get_Category | Returns one of the filter categories for this stream class driver. |
| get_ConnectionInfo | Returns information about one node connection in the filter. |
| get_NodeName | Returns the name of the node. |
| get_NodeType | Returns the node type for a given node. |
| get_NumCategories | Returns the number of categories for this filter. |
| get_NumConnections | Returns the number of node connections within the filter. |
| get_NumNodes | Returns the number of nodes in the filter. |
Requirements
Header: Include Vidcap.h.
Library: None.
Remarks
In the Windows Driver Model, a kernel-streaming (KS) filter contains one or more nodes. Each node encapsulates a processing task that is applied to the stream. Nodes have inputs and outputs, which connect either to other nodes in the filter, or else to the filter's pins. In this way, the nodes resemble a miniature "filter graph" inside the filter, which may contain several possible data paths. Applications can use the IKsTopologyInfo interface to get information about the nodes and the node connections.
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Some devices also support the ISelector interface for selecting input nodes. For example, if a video capture device has a camera and a tape transport, these could be represented as two nodes (see the previous diagram).
Requirements
Include Vidcap.h from the DirectX 9.0 SDK Update (Summer 2004) or later.
See Also