IWMEncDataView2::get_ViewAvailable
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The get_ViewAvailable method retrieves a value indicating whether the stream view is available.
Syntax
HRESULT get_ViewAvailable(
DWORD dwStreamCookie,
VARIANT_BOOL* pfAvail
);
Parameters
dwStreamCookie
[in] DWORD containing the stream cookie.
pfAvail
[out] Pointer to a VARIANT_BOOL that indicates availability.
Return Values
If the method succeeds, it returns S_OK. If it fails, it supports the IErrorInfo interface and returns an HRESULT error code.
| Return code | Number | Description |
| E_POINTER | 0x80004003 | The pointer to the Boolean value is NULL. |
Example Code
#include <windows.h>
#include <atlbase.h>
#include "C:\WMSDK\WMEncSDK9\include\wmencode.h"
#include "C:\WMSDK\WMEncSDK9\include\wmencvu.h"
#include <conio.h> // for kbhit()
// Declare variables.
HRESULT hr;
IWMEncoder* pEncoder;
IWMEncDataView* pPreview;
IWMEncDataView2* pPreview2;
IWMEncDataViewCollection* pPreviewColl;
IWMEncSourceGroupCollection* pSrcGrpColl;
IWMEncSourceGroup* pSrcGrp;
IWMEncSource* pSrcAud;
IWMEncSource* pSrcVid;
IWMEncProfileCollection* pProColl;
IWMEncProfile* pPro;
IWMEncBroadcast* pBrdCst;
CComBSTR bstrName = NULL;
// 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 an audio source and a video source.
if ( SUCCEEDED( hr ) )
{
hr = pSrcGrp->AddSource(WMENC_VIDEO, &pSrcVid);
}
if ( SUCCEEDED( hr ) )
{
hr = pSrcGrp->AddSource(WMENC_AUDIO, &pSrcAud);
}
// Specify the sources.
if ( SUCCEEDED( hr ) )
{
hr = pSrcVid->SetInput(CComBSTR("Device://default_video_device"));
}
if ( SUCCEEDED( hr ) )
{
hr = pSrcAud->SetInput(CComBSTR("Device://default_audio_device"));
}
// Specify the output.
if ( SUCCEEDED( hr ) )
{
hr = pEncoder->get_Broadcast(&pBrdCst);
}
if ( SUCCEEDED( hr ) )
{
hr = pBrdCst->put_PortNumber(WMENC_PROTOCOL_HTTP, 8080);
}
// Select the 5th profile from the collection and set it into the source group.
if ( SUCCEEDED( hr ) )
{
hr = pEncoder->get_ProfileCollection(&pProColl);
}
if ( SUCCEEDED( hr ) )
{
hr = pProColl->Item(4, &pPro);
}
if ( SUCCEEDED( hr ) )
{
hr = pSrcGrp->put_Profile(CComVariant(pPro));
}
// 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 = pSrcVid->get_PreviewCollection( &pPreviewColl );
}
// Add the postiew object to the data view collection. If you set the
// cookie to -1, the encoder engine automatically generates a unique cookie.
long lCookie = -1;
if ( SUCCEEDED( hr ) )
{
hr = pPreviewColl->Add( pPreview, &lCookie);
}
// Continue configuring the encoder engine.
// Initialize the encoder engine.
if ( SUCCEEDED( hr ) )
{
hr = pEncoder->PrepareToEncode(VARIANT_TRUE);
}
// Start encoding.
if ( SUCCEEDED( hr ) )
{
hr = pEncoder->Start();
}
// Start viewing the stream in a pop-up window.
if ( SUCCEEDED( hr ) )
{
hr = pPreview->Start(lCookie);
}
// Retrieve a pointer to an IWMEncDataView2 interface.
if ( SUCCEEDED( hr ) )
{
hr = pPreview->QueryInterface(IID_IWMEncDataView2, (void**)&pPreview2);
}
// Set the view to available.
if ( SUCCEEDED( hr ) )
{
hr = pPreview2->put_ViewAvailable(lCookie, VARIANT_TRUE);
}
// Determine whether the view is available.
VARIANT_BOOL bIsViewAvailable;
if ( SUCCEEDED( hr ) )
{
hr = pPreview2->get_ViewAvailable(lCookie, &bIsViewAvailable);
}
// Set the frame rate to balanced.
if ( SUCCEEDED( hr ) )
{
hr = pPreview2->put_FrameRateBalance(lCookie, VARIANT_TRUE);
}
// Determine whether the frame rate is balanced.
VARIANT_BOOL bIsBalanced;
if ( SUCCEEDED( hr ) )
{
hr = pPreview2->get_FrameRateBalance(lCookie, &bIsBalanced);
}
// Determine whether the view is running.
VARIANT_BOOL bIsRunning;
if ( SUCCEEDED( hr ) )
{
hr = pPreview2->IsRunning(lCookie, &bIsRunning);
}
// Let the process run 10 seconds.
int i = 0;
while ( i < 100 )
{
MSG msg;
Sleep ( 100 );
while ( PeekMessage( &msg, 0, 0, 0, PM_REMOVE) )
{
TranslateMessage( &msg );
DispatchMessage( &msg );
}
i++;
}
// 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 ( pPreview )
{
pPreview->Release();
pPreview = NULL;
}
if ( pPreview2 )
{
pPreview2->Release();
pPreview2 = NULL;
}
if ( pPreviewColl )
{
pPreviewColl->Release();
pPreviewColl = NULL;
}
if ( pSrcGrpColl )
{
pSrcGrpColl->Release();
pSrcGrpColl = NULL;
}
if ( pSrcGrp )
{
pSrcGrp->Release();
pSrcGrp = NULL;
}
if ( pSrcAud )
{
pSrcAud->Release();
pSrcAud = NULL;
}
if ( pSrcVid )
{
pSrcVid->Release();
pSrcVid = NULL;
}
if ( pProColl )
{
pProColl->Release();
pProColl = NULL;
}
if ( pPro )
{
pPro->Release();
pPro = NULL;
}
if ( pEncoder )
{
pEncoder->Release();
pEncoder = NULL;
}
Requirements
Header: wmencvu.h
Library: wmprevu.dll
See Also