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| Microsoft DirectShow 9.0 | 
IVMRMixerControl9::SetAlpha
The SetAlpha method sets a constant alpha value that is applied to this video stream.
Syntax
HRESULT SetAlpha( DWORD dwStreamID, float Alpha );
Parameters
dwStreamID
[in] Specifies the input stream. This value corresponds to the input pin. For example, the first input pin is stream 0.
Alpha
[in] Specifies the alpha blending value to be applied to all the pixels in this stream.
Return Values
The method returns an HRESULT. Possible values include those in the following table.
| Value | Description | 
| S_OK | The method succeeded. | 
| VFW_E_NOT_CONNECTED | The pin is not connected. | 
Remarks
The alpha value specified can range from 0.0 (fully transparent) to 1.0 (full opaque).
Requirements
Header: Include D3d9.h, Vmr9.h.
Library: Use Strmiids.lib.
See Also