CBaseOutputPin Class

Article
06/30/2006

This is an abstract base class derived from the CBasePin class that provides support for the common memory transport. CBaseOutputPin connects only to an input pin that supplies an IMemInputPin interface (such as a pin class derived from the CBaseInputPin class), and provides methods for the filter to access that interface. Derive your output pins from this class for the easiest implementation.

An output pin must provide one or more media types when connected to an input pin. If the media type that returns an index size, for example, is not currently available, the output pin should return S_FALSE in the CBasePin::GetMediaType member function, and the base class will skip it.

Your output pin class methods (represented here with the class name CYourPin) should call CBaseOutputPin. For example, CYourPin::Active should call CBaseOutputPin::Active first, to see if it should proceed. CYourPin::Inactive should call CBaseOutputPin::Inactive first, to decommit the sample allocator and avoid deadlock problems with CBaseOutputPin::GetDeliveryBuffer.

All member functions in this class that return HRESULT and accept a pointer as a parameter return E_POINTER when passed a null pointer.

All IQualityControl method implementations are inherited from the CBasePin class and are not overridden by this class.

Protected Data Members

Member	Description
m_pAllocator	Pointer to the IMemAllocator interface for this pin.
m_pInputPin	Pointer to the input pin to which this pin is connected.

Member Functions

Member function	Description
CBaseOutputPin	Constructs a CBaseOutputPin object.

Overrideable Member Functions

Member function	Description
Active	Switches the pin to the active (running) mode.
BreakConnect	Releases the allocator and the IMemInputPin interface.
CheckConnect	Calls QueryInterface to retrieve an IMemInputPin interface.
CompleteConnect	Completes the connection.
DecideAllocator	Negotiates the allocator.
DecideBufferSize	Retrieves the number and size of buffers required for the transfer.
Deliver	Delivers an IMediaSample buffer to the connecting pin.
DeliverBeginFlush	Calls the IPin::BeginFlush method on the connected pin.
DeliverEndFlush	Calls IPin::EndFlush on the connected input pin to pass an end-flushing notification.
DeliverEndOfStream	Calls IPin::EndOfStream on the connected input pin to pass an end-of-stream notification.
DeliverNewSegment	Calls IPin::NewSegment on the connected input pin to pass a segment.
GetDeliveryBuffer	Returns an IMediaSample buffer suitable for passing across the connection.
Inactive	Switches the pin to the inactive (stopped) mode.
InitAllocator	Creates a default memory allocator. Override this to provide your own allocator or to provide no allocator.

Implemented IPin Methods

Method	Description
BeginFlush	Informs the pin to begin a flush operation. Implemented to return E_UNEXPECTED because it is an error to call this on an output pin.
EndFlush	Informs the pin to end a flush operation. Implemented to return E_UNEXPECTED because it is an error to call this on an output pin.
EndOfStream	Informs the pin that no additional data is expected until a new run command is issued. Implemented to return E_UNEXPECTED because it is an error to call this on an output 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.
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Last updated on Wednesday, April 13, 2005

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