IWMEncDataView::Stop

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The Stop method stops displaying a specific media stream.

Syntax

HRESULT Stop(
  DWORD  dwStreamCookie
);

Parameters

dwStreamCookie

[in]  DWORD containing the ID of the stream.

Return Values

If the method succeeds, it returns S_OK. If it fails, it supports the IErrorInfo interface and returns an HRESULT error code.

Example Code

// Include libraries.

#include <windows.h>
#include <atlbase.h>
#include "wmencode.h"
#include "wmencvu.h"

// Declare variables.

    HRESULT hr;
    IWMEncoder* pEncoder;
    IWMEncDataView* pPreview;
    IWMEncDataViewCollection* pPreviewColl;
    IWMEncSourceGroupCollection* pSrcGrpColl;
    IWMEncSourceGroup* pSrcGrp;
    IWMEncSource* pAudSrc;
    IWMEncSource* pVidSrc;
    IWMEncProfileCollection* pProColl;
    IWMEncProfile* pPro;

    long lCount;
    int i;

// Initialize the COM library and retrieve a pointer
// to an IWMEncoder interface.
hr = CoInitialize(NULL);
if ( SUCCEEDED( hr ) )
{
    hr = CoCreateInstance(CLSID_WMEncoder,
                          NULL,
                          CLSCTX_INPROC_SERVER,
                          IID_IWMEncoder,
                          (void**) &pEncoder);
}

// Retrieve a pointer to an IWMEncSourceGroupCollection
// interface.

if ( SUCCEEDED( hr ) )
{
    hr = pEncoder->get_SourceGroupCollection(&pSrcGrpColl);
}

// Add a source group to the collection.

if ( SUCCEEDED( hr ) )
{
    hr = pSrcGrpColl->Add(CComBSTR("SG_1"), &pSrcGrp);
}

// Add a video and an audio source to the source group.

if ( SUCCEEDED( hr ) )
{
    hr = pSrcGrp->AddSource(WMENC_VIDEO, &pVidSrc);
}
if ( SUCCEEDED( hr ) )
{
    hr = pSrcGrp->AddSource(WMENC_AUDIO, &pAudSrc);
}

// Identify the capture cards.

if ( SUCCEEDED( hr ) )
{
    hr = pVidSrc->SetInput(CComBSTR("DEVICE://Default_Video_Device"));
}
if ( SUCCEEDED( hr ) )
{
    hr = pAudSrc->SetInput(CComBSTR("DEVICE://Default_Audio_Device"));
}

// Choose a profile from the collection.

    CComBSTR bstrName = NULL;
if ( SUCCEEDED( hr ) )
{
    hr = pEncoder->get_ProfileCollection(&pProColl);
}
if ( SUCCEEDED( hr ) )
{
    hr = pProColl->get_Count(&lCount);
}

for (i=0; i<lCount; i++)
{
 if ( SUCCEEDED( hr ) )
    {
        hr = pProColl->Item(i, &pPro);
    }

 if ( SUCCEEDED( hr ) )
    {
        hr = pPro->get_Name(&bstrName);
    }

    if (_wcsicmp(bstrName,CComBSTR("Windows Media Video 8 for Local Area Network (384 Kbps)"))==0)
    {
        // Set the profile in the source group.
     if ( SUCCEEDED( hr ) )
        {
            hr = pSrcGrp->put_Profile(CComVariant(pPro));
        }
        break;
    }
}

// Retrieve a pointer to a preview object.

if ( SUCCEEDED( hr ) )
{
    hr = CoCreateInstance( CLSID_WMEncPreview,
                           NULL,
                           CLSCTX_INPROC_SERVER,
                           IID_IWMEncDataView,
                           (void**)&pPreview);
}

// Retrieve the preview collection.

if ( SUCCEEDED( hr ) )
{
    hr = pVidSrc->get_PreviewCollection( &pPreviewColl );
}

// Add the preview object to the data view collection. If you set the
// cookie to -1, the encoding process automatically generates a unique
// cookie.

    long lCookie = -1;
if ( SUCCEEDED( hr ) )
{
    hr = pPreviewColl->Add( pPreview, &lCookie);
}

// Continue configuring the encoding session.

// Initialize the encoding process.

if ( SUCCEEDED( hr ) )
{
    hr = pEncoder->PrepareToEncode(VARIANT_TRUE);
}

// Create a parent window for the preview object, and specify the window
// settings for the encoding session. For instance, you can create a
// window by using the Win32 API function CreateWindow() and pass the
// window handle retrieved from this function to the
// SetViewSetting() method.
// Windows Media Encoder embeds the preview window in the parent window.
// If you do not create a parent window and specify the display
// settings, Windows Media Encoder creates a default window for the
// preview.

    HWND hWnd;
if ( SUCCEEDED( hr ) )
{
    hr = pPreview->SetViewSetting((DWORD) lCookie,
                                   sizeof(hWnd),
                                  (BYTE*)&hWnd);
}

// Start the encoding process.

if ( SUCCEEDED( hr ) )
{
    hr = pEncoder->Start();
}

// Start viewing the stream in a pop-up window.

if ( SUCCEEDED( hr ) )
{
    hr = pPreview->Start(lCookie);
}

// When finished, stop the preview.

if ( SUCCEEDED( hr ) )
{
    hr = pPreview->Stop(lCookie);
}

// Stop the encoding process.

if ( SUCCEEDED( hr ) )
{
    hr = pEncoder->Stop();
}

// Release pointers.
if ( pEncoder )
{
    pEncoder->Release();
    pEncoder = NULL;
}
if ( pPreview )
{
    pPreview->Release();
    pPreview = NULL;
}
if ( pPreviewColl )
{
    pPreviewColl->Release();
    pPreviewColl = NULL;
}
if ( pSrcGrpColl )
{
    pSrcGrpColl->Release();
    pSrcGrpColl = NULL;
}
if ( pSrcGrp )
{
    pSrcGrp->Release();
    pSrcGrp = NULL;
}
if ( pAudSrc )
{
    pAudSrc->Release();
    pAudSrc = NULL;
}
if ( pVidSrc )
{
    pVidSrc->Release();
    pVidSrc = NULL;
}
if ( pProColl )
{
    pProColl->Release();
    pProColl = NULL;
}
if ( pPro )
{
    pPro->Release();
    pPro = NULL;
}

Requirements

Header: wmencvu.h

Library: wmprevu.dll

See Also