CSALLOCATOR_FRAMING (Windows Embedded CE 6.0)

1/6/2010

This structure is used to query framing requirements and submit allocator creation requests.

Syntax

typedef struct {
  union {
    ULONG OptionsFlags;
    ULONG RequirementsFlags;
  };
  ULONG   PoolType;
  ULONG   Frames;
  ULONG   FrameSize;
  ULONG   FileAlignment;
  ULONG   Reserved;
} CSALLOCATOR_FRAMING, *PCSALLOCATOR_FRAMING;

Members

• OptionsFlags
  Not used. Set to 0.

• RequirementsFlags
  Not used. Set to 0.

• PoolType
  Not used. Set to 0.

• Frames
  A ULONG value that specifies the total number of frames. When the driver is the allocator, Frames identifies the number of rames that the driver will allocate. When the DirectShow middleware is the allocator, Frames is the number of frames that the driver is requesting DirectShow to allocate. Zero indicates that the filter has no requirement for this member.

  When the DirectShow is the allocator, this is the number of frames that will be allocated regardless of whether that number of frames is actually needed in practice. You should tune this value to the driver's exact needs. Doing so will maintain the driver's performance while reducing its working set.

• FrameSize
  A ULONG value that specifies the total size of the frame including prefix and postfix. Zero indicates that the filter has no requirement for this member.

• FileAlignment
  A ULONG value that specifies the allocation alignments. The value is one of the FILE ALIGNMENT Values. The minimum allocation alignment is FILE_BYTE_ALIGNMENT. Software that functions as an allocator should support FILE_QUAD_ALIGNMENT if possible. For hardware that requires 4-byte aligend data, set this value to FILE_LONG_ALIGNMENT.

• Reserved
  Reserved for system use. Set to zero.

Requirements

See Also

Reference

Camera Driver Structures
CSALLOCATOR Values
FILE ALIGNMENT Values