LEADTOOLS Media Foundation Help > Programming with LEADTOOLS Media Foundation > How To > Use ltmfCapture to Perform a Capture and Save It as a WMV File |
The format to be used to save the captured file. This includes the file format, any special settings used by that format, and which audio and/or video codec is to be used for the conversion and saving, and any special settings used by the codecs.
A COmpressor combined with a DECompressor, or encoder and a decoder, which allows you to both compress and decompress that same data.
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);
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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 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);
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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. |
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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.wmv");
IltmfCapture_put_TargetFile(pCapture, bstr);
SysFreeString(bstr);
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. |
When you want 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. |
When you want 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. |