DXVAHD_STREAM_STATE_ALPHA_DATA structure (dxvahd.h)
Specifies the planar alpha value for an input stream, when using Microsoft DirectX Video Acceleration High Definition (DXVA-HD).
Syntax
typedef struct _DXVAHD_STREAM_STATE_ALPHA_DATA {
BOOL Enable;
FLOAT Alpha;
} DXVAHD_STREAM_STATE_ALPHA_DATA;
Members
Enable
If TRUE, alpha blending is enabled. Otherwise, alpha blending is disabled. The default state value is FALSE.
Alpha
Specifies the planar alpha value as a floating-point number from 0.0 (transparent) to 1.0 (opaque).
If the Enable member is FALSE, this member is ignored.
Remarks
For each pixel, the destination color value is computed as follows:
Cd = Cs * (As * Ap * Ae) + Cd * (1.0 - As * Ap * Ae)
where
Cd= Color value of the destination pixel.Cs= Color value of source pixel.As= Per-pixel source alpha.Ap= Planar alpha value.Ae= Palette-entry alpha value, or 1.0 (see Note).
Note Palette-entry alpha values apply only to palettized color formats, and only when the device supports the DXVAHD_FEATURE_CAPS_ALPHA_PALETTE capability. Otherwise, this factor equals 1.0.
To get the device capabilities, call IDXVAHD_Device::GetVideoProcessorDeviceCaps and check the FeatureCaps member of the DXVAHD_VPDEVCAPS structure.
Examples
HRESULT DXVAHD_SetPlanarAlpha(
IDXVAHD_VideoProcessor *pVP,
UINT stream,
BOOL bEnable,
float fAlpha
)
{
DXVAHD_STREAM_STATE_ALPHA_DATA alpha = { bEnable, fAlpha };
HRESULT hr = pVP->SetVideoProcessStreamState(
stream,
DXVAHD_STREAM_STATE_ALPHA,
sizeof(alpha),
&alpha
);
return hr;
}
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 7 [desktop apps only] |
| Minimum supported server | Windows Server 2008 R2 [desktop apps only] |
| Header | dxvahd.h |