IVMRMixerControl9::SetMixingPrefs method (vmr9.h)

Article
4/26/2023

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 SetMixingPrefs method sets the mixing preferences for the stream.

Syntax

HRESULT SetMixingPrefs(
  [in] DWORD dwMixerPrefs
);

Parameters

[in] dwMixerPrefs

Bitwise OR combination of VMR9MixerPrefs flags.

Return value

The method returns an HRESULT. Possible values include those in the following table.

Return code	Description
S_OK	The method succeeded.

Remarks

The flags for the mixing preferences are divided into three groups: decimation, filtering, and render target. The VMR9MixerPrefs enumeration defines bitmasks to isolate these flags:

MixerPref9_DecimateMask
MixerPref9_FilteringMask
MixerPref9_RenderTargetMask

You must specify a valid flag for each group. If you want to change a single flag, you can get the current preferences, remove the flag you don't want, and add the flag you want. For example:


// Get the current mixing preferences.
DWORD dwPrefs;
pMixControl->GetMixingPrefs(&dwPrefs);  

// Remove the current render target flag.
dwPrefs &= ~MixerPref_RenderTargetMask; 

// Add the render target flag that we want.
dwPrefs |= MixerPref_RenderTargetYUV;

// Set the new flags.
pMixControl->SetMixingPrefs(dwPrefs);

If the VMR is in renderless mode, you must set the allocator-presenter before calling SetMixingPrefs. Otherwise, the VMR cannot determine the capabilities of the Direct3D device.

Include DShow.h and D3d9.h before Vmr9.h.

Requirements


Minimum supported client	Windows XP with SP2 [desktop apps only]
Minimum supported server	Windows Server 2003 R2 [desktop apps only]
Target Platform	Windows
Header	vmr9.h
Library	Strmiids.lib