IVMRMixerControl::SetAlpha method (strmif.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The SetAlpha method sets a constant alpha value that is applied to this video stream.
Syntax
HRESULT SetAlpha(
[in] DWORD dwStreamID,
[in] float Alpha
);
Parameters
[in] dwStreamID
Specifies the input stream.
[in] Alpha
Specifies the alpha blending value to be applied to all the pixels in this stream.
Return value
If the method succeeds, it returns S_OK. If it fails, it returns an error code.
| Return code | Description |
|---|---|
|
The pin is not connected. |
Remarks
The alpha value specified can be between 0.0 (fully transparent) and 1.0 (full opaque).
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows XP with SP1 [desktop apps only] |
| Minimum supported server | Windows Server 2003 [desktop apps only] |
| Target Platform | Windows |
| Header | strmif.h (include Dshow.h) |
| Library | Strmiids.lib |