ALLOCATOR_PROPERTIES structure (strmif.h)

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 ALLOCATOR_PROPERTIES structure describes an allocator's count, size, alignment, and prefix properties.

Syntax

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

Members

cBuffers

Number of buffers created by the 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 IMediaSample::GetPointer method returns a pointer 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.

Requirements

Requirement	Value
Header	strmif.h (include Dshow.h)

See also

DirectShow Structures