CTransformOutputPin.DecideBufferSize method

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 DecideBufferSize method sets the buffer requirements.

Syntax

HRESULT DecideBufferSize(
   IMemAllocator        *pAlloc,
   ALLOCATOR_PROPERTIES *ppropInputRequest
);

Parameters

pAlloc

Pointer to the allocator's IMemAllocator interface.

ppropInputRequest

Pointer an ALLOCATOR_PROPERTIES structure that contains the input pin's buffer requirements.

Return value

Returns an HRESULT value.

Remarks

This method overrides the CBaseOutputPin::DecideBufferSize method. It calls the filter's pure virtual CTransformFilter::DecideBufferSize method, which the filter's derived class must implement.

Requirements