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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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

Requirement	Value
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

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