ALLOCATOR_PROPERTIES Structure

Contains the allocator's count, size, alignment, and prefix properties.

Syntax

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.