Using Media Foundation Transform Attributes

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In order to use the Attributes of any Media Foundation transform, perform the following steps:

1.	Get an interface of type IMFTransform by calling QueryInterface over the LEAD Transform Object:

IMFTransform *pTransform = NULL;

LEADTransform->QueryInterface(IID_IMFTransform, (void**) &pTransform);

2.	Get the attribute store:

IMFAttributes *pAttributes = NULL;

pTransform->GetAttributes(&pAttributes);

3.	get or set any attribute supported by the transform:

Get a Value

for example, get a long (UINT32) value which has a CLSID of MF_CLSID_SOMEATTRIBUTE

long unVal;
pAttributes->GetUINT32(MF_CLSID_SOMEATTRIBUTE, &unVal);

Set a Value

for example, set a long (UINT32) value to an attribute which has a CLSID of MF_CLSID_SOMEATTRIBUTE

long unVal = 10;
pAttributes->SetUINT32(MF_CLSID_SOMEATTRIBUTE, unVal);

4.	Release the attribute store (and all active objects) when you are finished.