Hier das test Prg,

Code:
if( fMPEG2 )
    {
        hr = pBuilder->RenderStream(&PIN_CATEGORY_PREVIEW,
                                         &MEDIATYPE_Stream, pVCap, pGrabBase, NULL);
        if( FAILED( hr ) )
        {
            ErrMsg(TEXT("Cannot build MPEG2 preview graph!"));
        }

    }
    else
    {
        hr = pBuilder->RenderStream(&PIN_CATEGORY_PREVIEW,
                                         &MEDIATYPE_Interleaved, pVCap, pGrabBase, NULL);
        if(hr == VFW_S_NOPREVIEWPIN)
        {
            // preview was faked up for us using the (only) capture pin
            fPreviewFaked = TRUE;
        }
        else if(hr != S_OK)
        {
            // maybe it's DV?
            hr = pBuilder->RenderStream(&PIN_CATEGORY_PREVIEW,
                                             &MEDIATYPE_Video, pVCap, pGrabBase, NULL);
            if(hr == VFW_S_NOPREVIEWPIN)
            {
                // preview was faked up for us using the (only) capture pin
                fPreviewFaked = TRUE;
            }
            else if(hr != S_OK)
            {
                ErrMsg(TEXT("This graph cannot preview!"));
                fPreviewGraphBuilt = FALSE;
                return FALSE;
            }
        }

        //
        // Render the closed captioning pin? It could be a CC or a VBI category pin,
        // depending on the capture driver
        //

        if(fCapCC)
        {
            hr = pBuilder->RenderStream(&PIN_CATEGORY_CC, NULL,
                                             pVCap, NULL, NULL);
            if(hr != NOERROR)
            {
                hr = pBuilder->RenderStream(&PIN_CATEGORY_VBI, NULL,
                                                 pVCap, NULL, NULL);
                if(hr != NOERROR)
                {
                    ErrMsg(TEXT("Cannot render closed captioning"));
                }
            }
        }
    }
MS:

// build the preview graph!
//
// !!! PLEASE NOTE !!! Some new WDM devices have totally separate capture
// and preview settings. An application that wishes to preview and then
// capture may have to set the preview pin format using IAMStreamConfig on the
// preview pin, and then again on the capture pin to capture with that format.
// In this sample app, there is a separate page to set the settings on the
// capture pin and one for the preview pin. To avoid the user
// having to enter the same settings in 2 dialog boxes, an app can have its own
// UI for choosing a format (the possible formats can be enumerated using
// IAMStreamConfig) and then the app can programmatically call IAMStreamConfig