Access a Filter Interface

The example shows how to access the mosaic filter that was inserted as the first filter to the play object in the Programmatically Inserting a Processor Filter tutorial.

  1. Call the play object to retrieve the first selected video processor as follows:

C Source

IUnknown *pUnk;   
IltmmPlay_GetSubObject(pPlay, ltmmPlay_Object_SelVideoProcessor, &pUnk); 

C++ Source

IUnknown *pUnk;   
pPlay->GetSubObject(ltmmPlay_Object_SelVideoProcessor, &pUnk); 

  1. Retrieve the mosaic interface as follows:

C Source

ILMVMosaic *pVMF;   
IUnknown_QueryInterface(pUnk, &IID_ILMVMosaic, (void**) &pVMF);   
IUnknown_Release(pUnk); 

C++ Source

ILMVMosaic *pVMF;   
pUnk->QueryInterface(&IID_ILMVMosaic, (void**) &pVMF);   
pUnk->Release(); 

  1. Access the mosaic filter. For example, set the mosaic filter effect area rectangle.

C Source

CROP_ATTRIBUTES CropAttrib;   
CropAttrib.lLeft = 0;   
CropAttrib.lTop = 0;   
CropAttrib.lRight = 0;   
CropAttrib.lBottom = 0;   
CropAttrib.bEnabled = TRUE;   
ILMVMosaic_SetCropAttributes(pVMF, CropAttrib);   
IUnknown_Release(pVMF); 

C++ Source

CROP_ATTRIBUTES CropAttrib;   
CropAttrib.lLeft = 0;   
CropAttrib.lTop = 0;   
CropAttrib.lRight = 0;   
CropAttrib.lBottom = 0;   
CropAttrib.bEnabled = TRUE;   
pVMF->SetCropAttributes(CropAttrib);   
pVMF->Release(); 

  1. Clean up the play object.

C Source

IUnknown_Release(pPlay); 

C++ Source

pPlay->Release(); 

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