how to get audio and video when we play a .avi recorded file

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VisualC++

Hi i am using direct show filter graph in the following way.
FileSourceFilter -> AviSpliter ->AviMux -> FileWritterFilter.

then using IMediaControl Interface instance to run the Graph.After running the graph I get a recorded file but its size is bigger than the original .avi file.When i play it then it plays on window media player successfully but during playing I am not getting the voice or audio. the relevant code is pasted here.
the code for recording i implemented is as following...

BOOL CRecordingDlg::Record()
{
    UpdateData(TRUE);
	 HRESULT hr;
	 long evcode;
    
	 hr = CoInitialize(NULL);
	 if(FAILED(hr))
	 {
	   GetErrorMessage(hr);
	 }
	 
	 hr = CoCreateInstance(CLSID_FilterGraph,NULL,CLSCTX_INPROC_SERVER,IID_IGraphBuilder,(void**)&pGraph);
     if(FAILED(hr))
	 {
		 GetErrorMessage(hr);
	 }
	hr = pGraph->QueryInterface(IID_IMediaControl,(void**)&pControl);
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
    hr = pGraph->QueryInterface(IID_IMediaEvent,(void**)&pEvent);
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	hr = pGraph->AddSourceFilter( m_StrmUrl.AllocSysString(),L"Source",(IBaseFilter**)&pSource);
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	
	hr = CoCreateInstance(CLSID_AviSplitter,NULL,CLSCTX_INPROC_SERVER,IID_IBaseFilter,(void**)&pAviSpliter);  
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	hr = pGraph->AddFilter(pAviSpliter,L"AviSplitter");
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
    hr = CoCreateInstance(CLSID_AviDest,NULL,CLSCTX_INPROC_SERVER,IID_IBaseFilter,(void**)&pAviMux);
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	hr = pGraph->AddFilter(pAviMux,L"AviDest");
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	hr = CoCreateInstance(CLSID_FileWriter,NULL,CLSCTX_INPROC_SERVER,IID_IBaseFilter,(void**)&pFileWriter);
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	hr = pFileWriter->QueryInterface(IID_IFileSinkFilter2,(void**)&pSink);
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
	}
	hr = pGraph->AddFilter(pFileWriter,L"FileWriter");
	if(FAILED(hr))
	{
		AfxMessageBox(L"unable to Add");
		return FALSE;
	}
	hr = pSink->SetFileName(m_SaveFile.AllocSysString(),NULL); 
	if(FAILED(hr))
	{
		GetErrorMessage(hr);
    }
	ConnectPin(pGraph,pSource,pAviSpliter);
	ConnectPin(pGraph,pAviSpliter,pAviMux);
	ConnectPin(pGraph,pAviMux,pFileWriter);
     
        pControl->Run();
         hr = pEvent->WaitForCompletion(INFINITE,&evcode);
        if(evcode!=EC_COMPLETE)
       return FALSE;
       pControl->Stop();
      AfxMessageBox(L"File is recorded");
       return TRUE;
}
//Definition for connecting the pin
BOOL CRecordingDlg::ConnectPin(IGraphBuilder *pGraph,IBaseFilter *from,IBaseFilter *to)
{
	HRESULT hr;
	CComPtr<ipin> fPin,tPin;
	if(!(fPin = Getnextpin(from, PINDIR_OUTPUT)))
		return FALSE;
	if(!(tPin = Getnextpin(to,PINDIR_INPUT)))
		return FALSE;
	hr = pGraph->Connect(fPin,tPin);
   if(FAILED(hr))
   {
		GetErrorMessage(hr);
   }
	return TRUE;
}
//Definition for getting the next pin

Pin* CRecordingDlg::Getnextpin(IBaseFilter *base,PIN_DIRECTION dir)
{
	HRESULT hr;
    PIN_DIRECTION pindir;
    CComPtr<ienumpins> ep;
    IPin *pin, *buddy, *found = NULL;

    hr = base->EnumPins(&ep);
    if (FAILED(hr))
        return NULL;

    while (ep->Next(1, &pin, NULL) == S_OK) 
	{
        pin->QueryDirection(&pindir);
        if (pindir == dir) 
		{
            hr = pin->ConnectedTo(&buddy);
            if (FAILED(hr)) 
			{
                found = pin;
                break;
            }
            buddy->Release();
        }
        pin->Release();
    }

    return found;
}

there also some problem to stop the recording when i try to stop the recording using pcontrol->stop method then nothig is happening.so plz tell me any one how to control the recording play the recorded file with voice or audio.
thanks in advance