1. |
Create an instance of the ltmmCapture class. This is accomplished using the Win32 CoCreateInstance function, as follows: |
C Source
IltmmCapture* pCapture;
CoCreateInstance(&CLSID_ltmmCapture, NULL, CLSCTX_INPROC_SERVER,&IID_IltmmCapture,(void**) &pCapture);
C++ Source
IltmmCapture* pCapture;
CoCreateInstance(&CLSID_ltmmCapture, NULL, CLSCTX_INPROC_SERVER,&IID_IltmmCapture, (void**) &pCapture);
2. |
Define the notification window, which receives the capture status notifications: |
C Source
HWND hwndNotify;
#define WM_CAPTURENOTIFY (WM_USER + 1000)
IltmmCapture_SetNotifyWindow(pCapture, (long) hwndNotify, WM_CAPTURENOTIFY);
C++ Source
HWND hwndNotify;
#define WM_CAPTURENOTIFY (WM_USER + 1000)
pCapture->SetNotifyWindow((long) hwndNotify, WM_CAPTURENOTIFY);
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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. |
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Note: A capture can be accomplished without using a notification window, but the user would be required to poll the object’s state to determine when the capture has finished. |
3. |
Define a frame window for the video preview: |
C Source
HWND hwndFrame;
IltmmCapture_put_VideoWindowFrame(pCapture, (long) hwndFrame);
C++ Source
HWND hwndFrame;
pCapture->put_VideoWindowFrame((long) hwndFrame);
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The user is required to create the window that serves as the video frame. ltmmCapture will subclass this window, so there is no need to forward any messages to the ltmmCapture object. By default, ltmmCapture will automatically maximize the video within the frame window. The video will automatically resize when the frame window size changes. |
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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.asf");
IltmmCapture_put_TargetFile(pCapture, bstr);
SysFreeString(bstr);
C++ Source
BSTR bstr;
::SysAllocString(L"c:\\captured.asf");
pCapture->put_TargetFile(bstr);
::SysFreeString(bstr);
5. |
Set the video device: |
C Source
IltmmDevices* devices;
IltmmCapture_get_VideoDevices(pCapture, &devices);
IltmmDevices_put_Selection(devices, 0);
IltmmDevices_Release(devices);
C++ Source
IltmmDevices* devices;
pCapture->get_VideoDevices(&devices);
devices->put_Selection(0);
devices->Release();
6. |
Set the audio device: |
C Source
HIltmmDevices* devices;
IltmmCapture_get_AudioDevices(pCapture, &devices);
IltmmDevices__put_Selection(devices, 0);
IltmmDevices_Release(devices);
C++ Source
IltmmDevices* devices;
pCapture->get_AudioDevices(&devices);
devices->put_Selection(0);
devices->Release();
7. |
Set the target format: |
C Source
IltmmCapture_put_TargetFormat(pCapture, ltmmCapture_TargetFormat_Asf);
C++ Source
pCapture->put_TargetFormat(ltmmCapture_TargetFormat_Asf);
8. |
When you want to start capturing, call the StartCapture function as follows: |
C Source
IltmmCapture_StartCapture(pCapture, ltmmCapture_Mode_VideoAndAudio)
C++ Source
pCapture->StartCapture(ltmmCapture_Mode_VideoAndAudio);
9. |
When you want to stop capturing, call the StopCapture function as follows: |
C Source
IltmmCapture_StopCapture(pCapture);
C++ Source
pCapture->StopCapture();
10. |
Release the capture object (and all active objects) when you are done. |