Share via

CBaseOutputPin::DecideAllocator

  • Article

Negotiates the allocator to use.

virtual HRESULT DecideAllocator(
  IMemInputPin* pPin,
  IMemAllocator** pAlloc
);

Parameters

  • pPin
    Pointer to the IPin interface of the connecting pin.
  • pAlloc
    Pointer to the negotiated IMemAllocator interface.

Return Values

Returns NOERROR if successful; otherwise, returns an HRESULT value.

Remarks

This member function calls the CBaseOutputPin::DecideBufferSize member function, which is not implemented by this base class. Override DecideBufferSize to call IMemAllocator::SetProperties.

If the connected input pin fails a call to IMemInputPin::GetAllocator, this member function constructs a CMemAllocator object and calls CBaseOutputPin::DecideBufferSize on that object. If the call to DecideBufferSize is successful, this member function notifies the input pin of the selected allocator. This function is called by the base class implementation of the IPin::Connect method, which is responsible for locking the object's critical section.

Override this member function if you want to use your own allocator. The input pin gets the first choice for the allocator, and the output pin agrees or forces it to use another allocator.

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.
Header:

Last updated on Wednesday, April 13, 2005

© 2005 Microsoft Corporation. All rights reserved.