MFPKEY_EXATTRIBUTE_SUPPORTED property

Specifies whether a Media Foundation transform (MFT) copies attributes from input samples to output samples.

Data type

PROPVARIANT type (vt)

PROPVARIANT member

VARIANT_BOOL

VT_BOOL

boolVal

Remarks

This attribute can have the following values.

Value	Description
VARIANT_TRUE	The MFT copies attributes from the input samples to the output samples.
VARIANT_FALSE	The Media Session copies attributes from input samples to output samples. It does not overwrite any attributes that the MFT sets on the output samples.

 

To get this attribute, call QueryInterface on the MFT for the IPropertyStore interface.

The default value is VARIANT_FALSE. If the MFT does not expose the IPropertyStore interface, or if this property is not set, treat the value as VARIANT_FALSE.

This property is read-only.

Note

This attribute does not apply to asynchronous MFTs. Attributes will not be copied from the input samples to the output samples for asynchronous MFTs, regardless of the value of this attribute.

Examples

The following example returns VARIANT_TRUE if an MFT copies sample attributes.

BOOL TransformCopiesSampleAttributes(IMFTransform *pMFT)
{
    BOOL bCopiesAttributes = FALSE;

    IPropertyStore *pProps = NULL;

    HRESULT hr = pMFT->QueryInterface(IID_PPV_ARGS(&pProps));
    
    if (SUCCEEDED(hr))
    {
        PROPVARIANT var;
        hr = pProps->GetValue(MFPKEY_EXATTRIBUTE_SUPPORTED, &var);

        if (SUCCEEDED(hr))
        {
            bCopiesAttributes = 
                (var.vt == VT_BOOL && var.boolVal == VARIANT_TRUE);

            PropVariantClear(&var);
        }
        pProps->Release();
    }
    return bCopiesAttributes;
}

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Header	Mftransform.h

See also

Media Foundation Properties

Sample Attributes

IMFTransform::ProcessOutput