PFND3DDDI_DECODEEXECUTE callback function (d3dumddi.h)

Article
04/01/2021

The DecodeExecute function performs a decode operation by using the given Microsoft DirectX Video Accelerator (VA) decode device.

Syntax

PFND3DDDI_DECODEEXECUTE Pfnd3dddiDecodeexecute;

HRESULT Pfnd3dddiDecodeexecute(
  HANDLE hDevice,
  const D3DDDIARG_DECODEEXECUTE *unnamedParam2
)
{...}

Parameters

hDevice

A handle to the display device (graphics context).

unnamedParam2

pData [in]

A pointer to a D3DDDIARG_DECODEEXECUTE structure that describes the DirectX VA decode operation to perform.

Return value

DecodeExecute returns one of the following values:

Return code	Description
S_OK	The DirectX VA decode operation is successfully performed.
E_OUTOFMEMORY	DecodeExecute could not allocate the required memory for it to complete.

Remarks

The Microsoft Direct3D runtime calls the DecodeExecute function for all of the standard DirectX VA decode operations. When DecodeExecute is first called for each frame, the D3DDDIARG_DECODEEXECUTE structure that is specified by pData should contain all of the buffer information that is required for decoding the frame. DecodeExecute can subsequently be called for the same frame; however, these calls require only incremental data. If the GUID for the particular DirectX VA decode type does not use a buffer that is specified in D3DDDIARG_DECODEEXECUTE, the handle and description for the buffer are set to NULL. For example, because the MPEG2 decode type requires picture parameters, a macroblock buffer, and a residual-difference buffer, all of these items must be present in the first call for each frame. Depending on the size of the data, however, the Direct3D runtime might call DecodeExecute again to supply only additional residual-difference data that is required to decode the entire frame.

DirectX VA 1.0 supported an external synchronization mechanism through a call to the DdMoCompQueryStatus function. In DirectX VA 2.0, the user-mode display driver should perform its own synchronization, similar to the way it synchronizes the 3-D pipe. For more information about this synchronization, see Synchronizing Video Decode Operations.

Requirements

Requirement	Value
Minimum supported client	Available in Windows Vista and later versions of the Windows operating systems.
Target Platform	Desktop
Header	d3dumddi.h (include D3dumddi.h)