DirectShow Events Sample Code (Compact 2013)

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3/26/2014

The following sample code renders a file named boys.avi inside a video window. The sample shows how to respond to events that occur in a DirectShow application.

The following code does not include the functions WinMain or WindowProc. See the sample code in Sample DirectShow Video Window Program for these functions.

Note

For readability, the following code example does not contain security checking or error handling. Do not use the following code in a production environment.
Filenames in Windows Embedded Compact start with "\", not a drive letter.

#include <windows.h>
#include <streams.h>

#define WM_GRAPHNOTIFY  WM_APP + 1
#define CLASSNAME "EventNotify"

IGraphBuilder   *pGraph = NULL;
IMediaControl   *pMediaControl = NULL;
IMediaEventEx   *pEvent = NULL;
HWND            g_hwnd;

void PlayFile(void)
{
    // Create the filter graph manager and render the file.
    CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC, IID_IGraphBuilder, (void **)&pGraph);
    // Filenames start with a \\ instead of a drive letter.
    pGraph->RenderFile(L"\\Media\\Boys.wmv", NULL);

    // Specify the owner window.
    IVideoWindow    *pVidWin = NULL;
    pGraph->QueryInterface(IID_IVideoWindow, (void **)&pVidWin);
    pVidWin->put_Owner((OAHWND)g_hwnd);
    pVidWin->put_WindowStyle( WS_CHILD | WS_CLIPSIBLINGS);

    // Set the owner window to receive event notices.
    pGraph->QueryInterface(IID_IMediaEventEx, (void **)&pEvent);
    pEvent->SetNotifyWindow((OAHWND)g_hwnd, WM_GRAPHNOTIFY, 0);

    // Run the graph.
    pGraph->QueryInterface(IID_IMediaControl, (void **)&pMediaControl);
    pMediaControl->Run();
}

void CleanUp(void)
{
    IVideoWindow    *pVidWin = NULL;
    pGraph->QueryInterface(IID_IVideoWindow, (void **)&pVidWin);
    pVidWin->put_Visible(OAFALSE);
    pVidWin->put_Owner(NULL);

    // Stop the graph.
    pMediaControl->Stop();

    long evCode;
    pEvent->WaitForCompletion(INFINITE, &evCode);

    pMediaControl->Release();
    pEvent->Release();
    pGraph->Release();
    pGraph = NULL;

    pVidWin->Release();
    pVidWin = NULL;
    pMediaControl = NULL;
    pEvent = NULL;

    PostQuitMessage(0);
}

void HandleEvent() 
{
    long evCode, param1, param2;
    HRESULT hr;
    while (hr = pEvent->GetEvent(&evCode, &param1, &param2, 0), SUCCEEDED(hr))
    { 
        hr = pEvent->FreeEventParams(evCode, param1, param2);
        if ((EC_COMPLETE == evCode) || (EC_USERABORT == evCode))
        { 
            CleanUp();
            break;
        } 
    } 
}

/* WindowProc goes here. Add the following case statement:
        case WM_GRAPHNOTIFY:
            HandleEvent();
            break;
*/

// WinMain goes here.

See Also

Tasks

DirectShow Samples