ALLOCATOR_PROPERTIES

  • Article

This structure contains the allocator's count, size, alignment, and prefix properties.

typedef struct _AllocatorProperties {
  long cBuffers;
  long cbBuffer;
  long cbAlign;
  long cbPrefix;
} ALLOCATOR_PROPERTIES;

Members

  • cBuffers
    Count of buffers at this allocator.
  • cbBuffer
    Size of each buffer in bytes, excluding any prefix.
  • cbAlign
    Alignment of the buffer; buffer start will be aligned on a multiple of this value.
  • cbPrefix
    Each buffer is preceded by a prefix of this many bytes.

Remarks

The CMediaSample::GetPointer member function points to the beginning of the buffer, not including the prefix bytes designated by cbPrefix.

The alignment is applied to the prefix data, if any. If a nonzero prefix is used, the beginning of the prefix is aligned according to cbAlign. Since the buffer pointer returned by IMediaSample::GetPointer points to the area immediately following the prefix, the cbPrefix address (the value returned by IMediaSample::GetPointer minus cbPrefix) should be aligned on an address that is a multiple of cbAlign bytes.

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: Dshow.h.

Last updated on Wednesday, April 13, 2005

© 2005 Microsoft Corporation. All rights reserved.