Using Media Foundation Transform Attributes

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.