DxApi function (dxapi.h)

Article
04/01/2021
2 minutes to read

The DxApi function accepts commands from the hardware decoder's video capture driver to access the DxApi interface functions that are implemented in a video miniport driver.

Syntax

ULONG DxApi(
  IN ULONG dwFunctionNum,
  IN PVOID lpvInBuffer,
  IN ULONG cbInBuffer,
  IN PVOID lpvOutBuffer,
  IN ULONG cbOutBuffer
);

Parameters

dwFunctionNum

Indicates the behavior of the DxApi function (function identifier). See the Remarks section for the list of function identifiers.

lpvInBuffer

Points to the input buffer.

cbInBuffer

Indicates the size in bytes of the input buffer.

lpvOutBuffer

Points to the output buffer.

cbOutBuffer

Indicates the size in bytes of the output buffer.

Return value

DxApi returns the number of bytes actually written to the output buffer.

Remarks

DxApi accepts a function identifier (dwFunctionNum), an input buffer (lpvInBuffer) and its size (cbInBuffer), and an output buffer (lpvOutBuffer) and its size (cbOutBuffer). The behavior of the function and the size and format of the input and output buffers depend on the specified function identifier. The return value is the number of actual bytes written into the output buffer.

The following function identifiers are defined for the DxApi function in the ddkmapi.h header file:

DD_DXAPI_ADDVPCAPTUREBUFFER

DD_DXAPI_CLOSEHANDLE

DD_DXAPI_FLIP_OVERLAY

DD_DXAPI_FLIP_VP

DD_DXAPI_FLUSHVPCAPTUREBUFFERS

DD_DXAPI_GET_CURRENT_VP_AUTOFLIP_SURFACE

DD_DXAPI_GET_LAST_VP_AUTOFLIP_SURFACE

DD_DXAPI_GET_POLARITY

DD_DXAPI_GET_SURFACE_STATE

DD_DXAPI_GET_VP_FIELD_NUMBER

DD_DXAPI_GETKERNELCAPS