How to Control Capture Buffer Settings using the DVR Sink Object (C++)

The following method for C++ shows how to get the DVR Sink object from the ltmmPlayControl object, using it to set DVR settings.

void StartDVRCapture(IltmmCapture *pCapture, LPTSTR szBufferFile, long fileCount, double bufferSize)  
{  
   USES_CONVERSION;  
   HRESULT hr = S_OK;  
 
   pCapture->EnterEdit();  
   BSTR bstrBufferFile = SysAllocString(T2OLE(szBufferFile));  
 
    // Tell the capture control where to store the captured data  
   pCapture->put_TargetFile(bstrBufferFile);  
   SysFreeString(bstrBufferFile);  
 
   // Get the graph ready to capture video and audio, but don't start capturing yet  
   hr = pCapture->ReadyCapture(ltmmCapture_Mode_VideoAndAudio | ltmmCapture_Mode_InhibitRun);  
   if(SUCCEEDED(hr))  
   {  
      IUnknown *punk = NULL;  
      // Get the sink object unknown interface  
      hr = pCapture->GetSubObject(ltmmCapture_Object_Sink, &punk);  
      if(SUCCEEDED(hr) && NULL != punk)  
      { 
         ILMDVRSink *pDvrSink = NULL;  
         // Get the sink interface from the unknown object  
         HRESULT hr = punk->QueryInterface(IID_ILMDVRSink, (LPVOID*)&pDvrSink);  
          
         if (SUCCEEDED(hr))  
         {  
            // Tell the sink that settings are going to change  
            pDvrSink->StartChangingAttributes(); 
  
            // Set the folder count (one buffer folder) and number of buffer files and their maximum size  
            pDvrSink->put_FolderCount(1);  
            pDvrSink->SetBufferSize(0, fileCount, bufferSize);  
             
            // Apply the DVR settings  
            pDvrSink->StopChangingAttributes(FALSE); 
             
            // Release the sink interface  
            pDvrSink->Release();  
         } 
         // Release the unknown interface   
         punk->Release();  
      } 
      // Start the graph capturing data   
      hr = pCapture->RunCapture();  
   }  
   pCapture->LeaveEdit();  
}

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