共用方式為

IMemAllocator::SetProperties

  • 發行項
 
Microsoft DirectShow 9.0

IMemAllocator::SetProperties

The SetProperties method specifies the number of buffers to allocate and the size of each buffer.

Syntax

  HRESULT SetProperties(
  ALLOCATOR_PROPERTIES *pRequest,
  ALLOCATOR_PROPERTIES *pActual
);

Parameters

pRequest

Pointer to an ALLOCATOR_PROPERTIES structure that contains the buffer requirements.

pActual

Pointer to an ALLOCATOR_PROPERTIES structure that receives the actual buffer properties.

Return Values

Returns an HRESULT value. Possible values include those shown in the following table.

Return code Description
S_OK Success.
E_POINTER NULL pointer argument.
VFW_E_ALREADY_COMMITTED Cannot change allocated memory while the filter is active.
VFW_E_BADALIGN An invalid alignment was specified.
VFW_E_BUFFERS_OUTSTANDING One or more buffers are still active.

Remarks

This method specifies the buffer requirements, but does not allocate any buffers. Call the IMemAllocator::Commit method to allocate buffers.

The caller allocates two ALLOCATOR_PROPERTIES structures. The pRequest parameter contains the caller's buffer requirements, including the number of buffers and the size of each buffer. When the method returns, the pActual parameter contains the actual buffer properties, as set by the allocator.

When this method is called, the allocator must not be committed or have outstanding buffers.

Requirements

Header: Declared in Strmif.h; include Dshow.h.

Library: Use Strmiids.lib.

See Also