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UID title description helpviewer_keywords old-location tech.root ms.assetid ms.date ms.keywords req.header req.include-header req.target-type req.target-min-winverclnt req.target-min-winversvr req.kmdf-ver req.umdf-ver req.ddi-compliance req.unicode-ansi req.idl req.max-support req.namespace req.assembly req.type-library req.lib req.dll req.irql targetos req.typenames req.redist ms.custom f1_keywords dev_langs topic_type api_type api_location api_name
NF:d3d11.ID3D11VideoContext.VideoProcessorSetStreamAlpha
ID3D11VideoContext::VideoProcessorSetStreamAlpha (d3d11.h)
Sets the planar alpha for an input stream on the video processor.
ID3D11VideoContext interface [Media Foundation]
VideoProcessorSetStreamAlpha method
ID3D11VideoContext.VideoProcessorSetStreamAlpha
ID3D11VideoContext::VideoProcessorSetStreamAlpha
VideoProcessorSetStreamAlpha
VideoProcessorSetStreamAlpha method [Media Foundation]
VideoProcessorSetStreamAlpha method [Media Foundation]
ID3D11VideoContext interface
d3d11/ID3D11VideoContext::VideoProcessorSetStreamAlpha
mf.id3d11videocontext_videoprocessorsetstreamalpha
mf\id3d11videocontext_videoprocessorsetstreamalpha.htm
mf
DA869E3F-25BB-4794-B7AE-A3C2DA968800
12/05/2018
ID3D11VideoContext interface [Media Foundation],VideoProcessorSetStreamAlpha method, ID3D11VideoContext.VideoProcessorSetStreamAlpha, ID3D11VideoContext::VideoProcessorSetStreamAlpha, VideoProcessorSetStreamAlpha, VideoProcessorSetStreamAlpha method [Media Foundation], VideoProcessorSetStreamAlpha method [Media Foundation],ID3D11VideoContext interface, d3d11/ID3D11VideoContext::VideoProcessorSetStreamAlpha, mf.id3d11videocontext_videoprocessorsetstreamalpha
d3d11.h
Windows
Windows 8 [desktop apps \| UWP apps]
Windows Server 2012 [desktop apps \| UWP apps]
Windows
19H1
ID3D11VideoContext::VideoProcessorSetStreamAlpha
d3d11/ID3D11VideoContext::VideoProcessorSetStreamAlpha
c++
APIRef
kbSyntax
COM
d3d11.h
ID3D11VideoContext.VideoProcessorSetStreamAlpha

ID3D11VideoContext::VideoProcessorSetStreamAlpha

-description

Sets the planar alpha for an input stream on the video processor.

-parameters

-param pVideoProcessor [in]

A pointer to the ID3D11VideoProcessor interface. To get this pointer, call ID3D11VideoDevice::CreateVideoProcessor.

-param StreamIndex [in]

The zero-based index of the input stream. To get the maximum number of streams, call ID3D11VideoProcessorEnumerator::GetVideoProcessorCaps and check the MaxStreamStates structure member.

-param Enable [in]

Specifies whether alpha blending is enabled.

-param Alpha [in]

The planar alpha value. The value can range from 0.0 (transparent) to 1.0 (opaque). If Enable is FALSE, this parameter is ignored.

-remarks

To use this feature, the driver must support stereo video, indicated by the D3D11_VIDEO_PROCESSOR_FEATURE_CAPS_ALHPA_STREAM capability flag. To query for this capability, call ID3D11VideoProcessorEnumerator::GetVideoProcessorCaps.

Alpha blending is disabled by default.

For each pixel, the destination color value is computed as follows:

Cd = Cs * (As * Ap * Ae) + Cd * (1.0 - As * Ap * Ae)

where:

  • Cd = The color value of the destination pixel
  • Cs = The color value of the source pixel
  • As = The per-pixel source alpha
  • Ap = The planar alpha value
  • Ae = The 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 D3D11_VIDEO_PROCESSOR_FEATURE_CAPS_ALPHA_PALETTE capability. Otherwise, this factor equals 1.0.
 
The destination alpha value is computed according to the alpha fill mode. For more information, see ID3D11VideoContext::VideoProcessorSetOutputAlphaFillMode.

-see-also

ID3D11VideoContext