Programmatically Inserting a Processor Filter

Assume you want to insert the mosaic as the first filter to the play object.

  1. Create an instance of the ltmmPlay class. This is accomplished using the Win32 CoCreateInstance function as follows:

C Source

IltmmPlay* pPlay;   
CoCreateInstance(&CLSID_ltmmPlay, NULL, CLSCTX_INPROC_SERVER, &IID_IltmmPlay, (void**) &pPlay); 

C++ Source

IltmmPlay* pPlay;   
CoCreateInstance(CLSID_ltmmPlay, NULL, CLSCTX_INPROC_SERVER, IID_IltmmPlay, (void**) &pPlay); 

  1. Get the registered processors collection as follows:

C Source

IltmmProcessors* pProcessors;   
IltmmPlay_get_VideoProcessors (pPlay, &pProcessors); 

C++ Source

IltmmProcessors* pProcessors;   
pPlay->get_VideoProcessors(&pProcessors); 

  1. Find the processor index by name as follows:

C Source

long index; 
BSTR bstr; 
// The string below is retrieved from the Filters List utility 
bstr = SysAllocString(L"@device:sw:{E526D606-22E7-494C-B81E-AC0A94BFE603}\\{E2B7DB28-38C5-11D5-91F6-00104BDB8FF9}"); 
IltmmProcessors_Find (pProcessors, bstr, &index); 
SysFreeString(bstr); 

C++ Source

long index; 
BSTR bstr; 
// The string below is retrieved from the Filters List utility 
bstr = SysAllocString(L"@device:sw:{E526D606-22E7-494C-B81E-AC0A94BFE603}\\{E2B7DB28-38C5-11D5-91F6-00104BDB8FF9}"); 
pProcessors->Find (bstr, &index); 
SysFreeString(bstr); 

  1. Get the processor interface and the selected processors collection as follows:

C Source

IltmmProcessors* pSelProcessors;    
IltmmProcessor* pProcessor;   
// get the processor interface   
IltmmProcessors_Item(pProcessors, index, &pProcessor);    
// get the selected processors collection   
IltmmPlay_get_SelectedVideoProcessors (pPlay, &pSelProcessors); 

C++ Source

IltmmProcessors* pSelProcessors;    
IltmmProcessor* pProcessor;   
// get the processor interface   
pProcessors->Item (index, &pProcessor);    
// get the selected processors collection   
pPlay->get_SelectedVideoProcessors (&pSelProcessors); 

  1. Finally, add the processor to the selected processors collection as the first filter as follows:

C Source

IltmmProcessors_Add (pSelProcessors, pProcessor, 0);    
// release interfaces   
IUnknown_Release(pProcessor);    
IUnknown_Release(pProcessors);    
IUnknown_Release(pSelProcessors); 

C++ Source

pSelProcessors->Add (pProcessor, 0);    
// release interfaces   
pProcessor->Release();   
pProcessors->Release();   
pSelProcessors->Release(); 

Note: If you want to know how to use the interface of the filter, refer to Access the Interface of Filters.

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