callback

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Date: Tue, 10 Aug 2004 06:48:44 +0200

Hi,
I an writing an application that capture live video and display it to a
window i am using monikor and it work fine.
I try to derived a class from ISampleGrabberCB and catch the event callback
BufferCB function but it didnt work why??
How can i catch the BufferCB function???

Here is my code plesh tell me what i need to do to chact this event function
(i need every step)

//----------------For cam-----------------//

IVideoWindow* m_pVWMoniker ;

IMediaControl* m_pMCMoniker ;

IMediaEventEx* m_pMEMoniker ;

ICaptureGraphBuilder2* m_pCaptureMoniker ;

IFilterGraph2* m_pFilterGraph ;// IFilterGraph2 provides
AddSourceFileForMoniker()

//------------------------------------

class SampleGrabberCallback : public ISampleGrabberCB{// Fake referance
counting.... STDMETHODIMP SampleCB(double Time, IMediaSample *pSample) {
return E_NOTIMPL; } STDMETHODIMP BufferCB(double Time, BYTE *pBuffer,
long BufferLen) { ... }}//--------------------------
SampleGrabberCallback m_callBack;

where should i use m_callBack in the code below????

HRESULT hr;

IMoniker *pMoniker =NULL;

// Create the filter graph

hr = CoCreateInstance (CLSID_FilterGraph, NULL, CLSCTX_INPROC,

                                     IID_IFilterGraph2, (void **)
&m_pFilterGraph);

// Create the capture graph builder

hr = CoCreateInstance (CLSID_CaptureGraphBuilder2 , NULL, CLSCTX_INPROC,

                                    IID_ICaptureGraphBuilder2, (void **)
&m_pCaptureMoniker);

// Obtain interfaces for media control and Video Window

 hr = m_pFilterGraph->QueryInterface(IID_IMediaControl,(LPVOID *)
_pMCMoniker);

hr = m_pFilterGraph->QueryInterface(IID_IVideoWindow, (LPVOID *)
pVWMoniker);

hr = m_pFilterGraph->QueryInterface(IID_IMediaEvent, (LPVOID *)
m_pMEMoniker);

hr = m_pMEMoniker->SetNotifyWindow((OAHWND)m_hApp, M_GRAPHNOTIFY,0);

FindCaptureDeviceMoniker(IMoniker **ppMoniker)

{. while ((pClassEnum->Next (1.))..}//Get the capture device

IBaseFilter *pBaseFilter=0;

hr = m_pFilterGraph->AddSourceFilterForMoniker(pMoniker, pContext,
strMonikerName, &pBaseFilter);

// Attach the filter graph to the capture graph

 hr = m_pCaptureMoniker->SetFiltergraph(m_pFilterGraph);

// Render the preview pin on the video capture filter

// Use this instead of m_pGraph->RenderFile

 hr = m_pCaptureMoniker->RenderStream (&PIN_CATEGORY_PREVIEW,
&MEDIATYPE_Video,pBaseFilter, NULL, NULL);

SAFE_RELEASE(pContext);

SAFE_RELEASE(pBaseFilter);

// Release the IMoniker interface for the capture source filter

pMoniker->Release();

 // Set video window style and position

 hr = SetupVideoWindowMoniker();

// Start previewing video data

 hr = m_pMCMoniker->Run();

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