IKsTopologyInfo interface (vidcap.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
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.
Inheritance
The IKsTopologyInfo interface inherits from the IUnknown interface. IKsTopologyInfo also has these types of members:
Methods
The IKsTopologyInfo interface has these methods.
| IKsTopologyInfo::CreateNodeInstance The CreateNodeInstance method creates a COM object that represents a node in the filter. |
| IKsTopologyInfo::get_Category The get_Category method returns one of the filter categories for this stream class driver. |
| IKsTopologyInfo::get_ConnectionInfo The get_ConnectionInfo method returns information about one node connection in the filter. |
| IKsTopologyInfo::get_NodeName The get_NodeName method returns the name of the node. |
| IKsTopologyInfo::get_NodeType The get_NodeType method returns the node type for a given node. |
| IKsTopologyInfo::get_NumCategories The get_NumCategories method returns the number of categories for this filter. |
| IKsTopologyInfo::get_NumConnections The get_NumConnections method returns the number of node connections within the filter. |
| IKsTopologyInfo::get_NumNodes The get_NumNodes method returns the number of nodes in the filter. |
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.
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).
Include Vidcap.h from the Windows SDK or from the DirectX 9.0 SDK Update (Summer 2004) or later.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows XP with SP2 [desktop apps only] |
| Minimum supported server | Windows Server 2003 R2 [desktop apps only] |
| Target Platform | Windows |
| Header | vidcap.h |