ALLOCATOR_PROPERTIES (Compact 2013)

3/26/2014

This 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.

Requirements

See Also

Reference

DirectShow Structures