DXVADDI_DECODEBUFFERDESC structure (d3dumddi.h)

The DXVADDI_DECODEBUFFERDESC structure describes a buffer that is currently passed from the host decoder to the accelerator.

Syntax

typedef struct _DXVADDI_DECODEBUFFERDESC {
  [in] HANDLE            hBuffer;
  [in] D3DDDIFORMAT      CompressedBufferType;
  [in] UINT              BufferIndex;
  [in] UINT              DataOffset;
  [in] UINT              DataSize;
  [in] UINT              FirstMBaddress;
  [in] UINT              NumMBsInBuffer;
  [in] UINT              Width;
  [in] UINT              Height;
  [in] UINT              Stride;
  [in] UINT              ReservedBits;
  [in] DXVADDI_PVP_HW_IV *pCipherCounter;
} DXVADDI_DECODEBUFFERDESC;

Members

[in] hBuffer

A handle to the buffer.

[in] CompressedBufferType

A D3DDDIFORMAT-typed value that indicates the pixel format of the buffer.

[in] BufferIndex

Reserved. Do not use this member. For more information, see the Remarks section.

[in] DataOffset

The offset of the relevant data from the beginning of the buffer, in bytes. The use of this member is currently restricted to the value zero.

[in] DataSize

The amount of relevant data in the buffer, in bytes. The location of the last byte of content in the buffer is the value of DataOffset plus the value of DataSize minus 1.

[in] FirstMBaddress

The macroblock address of the first macroblock in the buffer that is passed to the accelerator. The macroblock address is given in raster scan order. The address is determined by the members of the DXVA_PictureParameters structure. The following table shows examples of macroblock addresses.

The FirstMBaddress member must be zero if the data buffer is one of the following types: picture decoding parameters, inverse-quantization matrix, slice control, bitstream data, AYUV, IA44/AI44, DPXD, Highlight, and DCCMD.

If the data buffer is a residual difference block data buffer, FirstMBaddress must have the same value as for the corresponding macroblock control command buffer.

[in] NumMBsInBuffer

The number of macroblocks of data in the buffer, including skipped macroblocks. This member must be zero if the data buffer is one of the following types: picture decoding parameters, inverse-quantization matrix, AYUV, IA44/AI44, DPXD, Highlight, or DCCMD.

The value for NumMBsInBuffer depends on the type of data buffer that is being used, as shown in the following table.

[in] Width

Reserved. Do not use this member. For more information, see the Remarks section.

[in] Height

Reserved. Do not use this member. For more information, see the Remarks section.

[in] Stride

Reserved. Do not use this member. For more information, see the Remarks section.

[in] ReservedBits

Reserved bits that are used for packing and alignment. This member must be zero.

[in] pCipherCounter

A pointer to a DXVADDI_PVP_HW_IV structure that contains a 128-bit protected video path (PVP) value.

Remarks

An array of DXVADDI_DECODEBUFFERDESC structures is referred to as a buffer description list. When a set of buffers is sent from the host decoder to the hardware accelerator, a buffer description list is sent to describe the buffers. The buffer description list contains one DXVADDI_DECODEBUFFERDESC structure for each buffer in this set. The buffer description list starts with a DXVADDI_DECODEBUFFERDESC structure for the first buffer of the first type, followed by a DXVADDI_DECODEBUFFERDESC structure for the next buffer of the same type, and so on. The buffer description list then continues with a DXVADDI_DECODEBUFFERDESC structure for the first buffer of the next type, and so on. This entire list is contained in a D3DDDIARG_DECODEEXECUTE structure.

Because Microsoft DirectX Video Acceleration (VA) version 2.0 uses Microsoft Direct3D surfaces rather than the private surfaces that DirectX VA 1.0 uses, the user-mode display driver obtains values for the index, width, height, and stride from the given compressed buffer type rather than from the values in the BufferIndex, Width, Height, and Stride members. In fact, the Microsoft Direct3D runtime sets these members to zero.

Requirements

See also

D3DDDIARG_DECODEEXECUTE

DXVADDI_PVP_HW_IV

DXVA_PictureParameters

DXVA_SliceInfo