Use ltmfCapture to Perform a Capture and Save It as a WMV File

  1. Create an instance of the ltmfCapture class. This is accomplished using the Win32 CoCreateInstance function,  as follows:

    //C Source 
    IltmfCapture* pCapture; 
    CoCreateInstance(&CLSID_ltmfCapture, NULL, CLSCTX_INPROC_SERVER,&IID_IltmfCapture,(void**) &pCapture); 
     
    //C++ Source 
    IltmfCapture* pCapture; 
    CoCreateInstance(&CLSID_ltmfCapture, NULL, CLSCTX_INPROC_SERVER,&IID_IltmfCapture, (void**) &pCapture); 

  2. Define the notification window, which receives the capture status notifications:

    //C Source 
    HWND hwndNotify; 
    #define WM_CAPTURENOTIFY (WM_USER + 1000) 
    IltmfCapture_SetNotifyWindow(pCapture, (long)hwndNotify, WM_CAPTURENOTIFY); 
     
    // C++ Source 
    HWND hwndNotify; 
    #define WM_CAPTURENOTIFY (WM_USER + 1000)  
    pCapture->SetNotifyWindow((long)hwndNotify, WM_CAPTURENOTIFY); 
    The above code instructs the capture object to send WM_CAPTURENOTIFY messages to the window procedure of hwndNotify. The wParam parameter of the window message will contain the notification code.

    ✎ NOTE

    A capture can be accomplished without using a notification window, but the user would be required to poll the objects state to determine when the capture has finished.

  3. Define a frame window for the video preview:

    //C Source 
    HWND  hwndFrame; 
    IltmfCapture_put_VideoWindowFrame(pCapture, (long)hwndFrame); 
     
    // C++ Source 
    HWND hwndFrame; 
    pCapture->put_VideoWindowFrame((long)hwndFrame); 

    The user is required to create the window that serves as the video frame. ltmfCapture will subclass this window, so there is no need to forward any messages to the ltmfCapture object. By default, ltmfCapture will automatically maximize the video within the frame window. The video will automatically resize when the frame window size changes.

    ✎ NOTE

    The notification window and the video frame window can be the same.

  4. Set the Target file:

    //C Source 
    BSTR bstr; 
    bstr = SysAllocString(L"c:\\captured.wmv"); 
    IltmfCapture_put_Target 
     
    // C++ Source 
    BSTR bstr; 
    ::SysAllocString(L"c:\\captured.wmv"); 
    pCapture->put_TargetFile(bstr); 
    ::SysFreeString(bstr); 

  5. Set the video device:

    //C Source 
    IltmfDevices* devices; 
    IltmfCapture_get_VideoDevices(pCapture, &devices); 
    IltmfDevices_put_Selection(devices, 0); 
    IltmfDevices_Release(devices); 
     
    // C++ Source 
    IltmfDevices* devices; 
    pCapture->get_VideoDevices(&devices); 
    devices->put_Selection(0); 
    devices->Release(); 

  6. Set the audio device:

    //C Source 
    HIltmfDevices* devices; 
    IltmfCapture_get_AudioDevices(pCapture, &devices); 
    IltmfDevices_put_Selection(devices, 0); 
    IltmfDevices_Release(devices); 
     
    //C++ Source 
    IltmfDevices* devices; 
    pCapture->get_AudioDevices(&devices); 
    devices->put_Selection(0); 
    devices->Release(); 

  7. Set the target format :

    //C Source 
    IltmfCapture_put_TargetFormat(pCapture, ltmfCapture_TargetFormat_WMV); 
     
    //C++ Source 
    pCapture->put_TargetFormat(ltmfCapture_TargetFormat_WMV); 

  8. To start capturing, call the StartCapture function as follows:

    //C Source 
    IltmfCapture_StartCapture(pCapture, ltmfCapture_Mode_VideoAndAudio) 
     
    //C++ Source 
    pCapture->StartCapture(ltmfCapture_Mode_VideoAndAudio); 

  9. To stop capturing, call the StopCapture function as follows:

    //C Source 
    IltmfCapture_StopCapture(pCapture); 
     
    //C++ Source 
    pCapture->StopCapture(); 

  10. Release the capture object (and all active objects) when you are done.

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