IPin Interface
This interface represents a single, unidirectional connection point on a filter. A pin connects to exactly one other pin on another filter. Other objects can use this interface on this pin. The interface between the filter and the pin is private to the implementation of a specific filter.
During the connection process, one pin takes the lead. The base classes assume that this is the output pin of the upstream connecting filter. The filter graph manager calls the IPin::Connect method on this pin's IPin interface, passing the IPin pointer for the connecting pin. This connecting pin then calls the IPin::ReceiveConnection method located on the other pin, in addition to its format-enumeration, IUnknown::QueryInterface, and possibly IPin::QueryAccept methods, to establish whether the connection is possible.
When to Implement
All filters must implement this interface on each of its pins. Which methods are implemented depends on whether the pin is an input pin or an output pin. Use the CBasePin, CBaseInputPin, or CBaseOutputPin class, or classes derived from these classes, to implement this interface.
When to Use
This interface is used by other connecting pins and by the filter graph manager. Applications should not use this interface directly but should go through the filter graph manager. Connecting pins use the IPin interface on the opposite pin to negotiate a common media type and an agreed allocator to use for passing samples.
Methods in Vtable Order
The following table shows the methods that appear in the Vtable beneath the standard COM methods inherited from IUnknown.
| Method | Description |
|---|---|
| Connect | Makes a connection to another pin. |
| ReceiveConnection | Makes a connection to this pin and is called by a connecting pin. |
| Disconnect | Breaks a connection. |
| ConnectedTo | Returns a pointer to the connecting pin. |
| ConnectionMediaType | Returns the media type of this pin's connection. |
| QueryPinInfo | Retrieves information about this pin (for example, the name, owning filter, and direction). |
| QueryId | Retrieves an identifier for the pin. |
| QueryAccept | Queries whether a given media type is acceptable by the pin. |
| EnumMediaTypes | Provides an enumerator for this pin's preferred media types. |
| QueryInternalConnections | Provides an array of the pins to which this pin internally connects. |
| EndOfStream | Informs the pin that no additional data is expected until a new run command is issued. |
| BeginFlush | Informs the pin to begin a flush operation. |
| EndFlush | Informs the pin to end a flush operation. |
| NewSegment | Specifies that samples following this call are grouped as a segment with a given start time, stop time, and rate. |
| QueryDirection | Retrieves the direction for this pin. |
Requirements
DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.
OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.
See Also
Last updated on Wednesday, April 13, 2005
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