IStreamBuilder::Render method (strmif.h)

Article
02/22/2024

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The Render method completes rendering of the stream originating with this pin. This can involve adding filters to the filter graph and connecting them.

Syntax

HRESULT Render(
  [in] IPin          *ppinOut,
  [in] IGraphBuilder *pGraph
);

Parameters

[in] ppinOut

Pointer to the IPin interface of this pin.

[in] pGraph

Pointer to the IGraphBuilder interface of the Filter Graph Manager.

Return value

Returns an HRESULT value. A return code of S_OK indicates that the stream was successfully rendered.

Remarks

The following code illustrates how to implement this method on an output pin. This example assumes that the filter requires a custom renderer downstream from it.

C++

C++
STDMETHODIMP CMyOutputPin::Render(IPin pPin, IGraphBuilder pGraph) { CheckPointer(pPin, E_POINTER); CheckPointer(pGraph, E_POINTER); // This filter needs a special renderer connected to it. IBaseFilter pMyRenderer = NULL; // Create the renderer. HRESULT hr = CoCreateInstance(CLSID_MyRenderer, NULL, CLSCTX_INPROC, IID_IBaseFilter, (void )&pMyRenderer); if (FAILED(hr)) { return hr; } // Add my renderer to the filter graph. hr = pGraph->AddFilter(pMyRenderer, L"My Renderer"); if (FAILED(hr)) { pMyRenderer->Release(); return hr; } IEnumPins pEnumPins; IPin *pMyRendererInputPin = NULL; hr = pMyRenderer->EnumPins(&pEnumPins); if (SUCCEEDED(hr)) { if (S_OK != pEnumPins->Next(1, &pMyRendererInputPin, 0)) { hr = E_UNEXPECTED; } } if (SUCCEEDED(hr)) { // Connect my renderer to my output pin. hr = pGraph->ConnectDirect(pPin, pMyRendererInputPin); pMyRendererInputPin->Release(); } if (FAILED(hr)) { // Could not connect to my renderer. Remove it from the graph. pGraph->RemoveFilter(pMyRenderer); } pMyRenderer->Release(); return hr; }

STDMETHODIMP CMyOutputPin::Render(IPin *pPin, IGraphBuilder *pGraph)
{
    CheckPointer(pPin, E_POINTER);
    CheckPointer(pGraph, E_POINTER);

    // This filter needs a special renderer connected to it.
    IBaseFilter *pMyRenderer = NULL;

    // Create the renderer.
    HRESULT hr = CoCreateInstance(CLSID_MyRenderer, NULL, CLSCTX_INPROC,
        IID_IBaseFilter, (void **)&amp;pMyRenderer);
    if (FAILED(hr))
    {
        return hr;
    }
    
    // Add my renderer to the filter graph.
    hr = pGraph-&gt;AddFilter(pMyRenderer, L"My Renderer");
    if (FAILED(hr))
    {
        pMyRenderer-&gt;Release();
        return hr;
    }

    IEnumPins *pEnumPins;
    IPin *pMyRendererInputPin = NULL;
    hr = pMyRenderer-&gt;EnumPins(&amp;pEnumPins);
    if (SUCCEEDED(hr)) 
    {
        if (S_OK != pEnumPins-&gt;Next(1, &amp;pMyRendererInputPin, 0))
        {
            hr = E_UNEXPECTED;
         }
    }
    if (SUCCEEDED(hr)) 
    {
        // Connect my renderer to my output pin.
        hr = pGraph-&gt;ConnectDirect(pPin, pMyRendererInputPin);
        pMyRendererInputPin-&gt;Release();
    }
    if (FAILED(hr)) 
    {
        // Could not connect to my renderer. Remove it from the graph.
        pGraph-&gt;RemoveFilter(pMyRenderer);
    }
    pMyRenderer-&gt;Release();
    return hr;
}

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib