The following code demonstrates how to enumerate, add, and select ltmmCapture object target formats:
#include "ltmm.h" #include "resource.h" #include "tchar.h" #include "stdio.h" HINSTANCE g_hInstance; // application instance handle IltmmCapture* g_pCapture; // capture object's interface pointer // // BuildTargetFormatList // fills a listbox to match the contents of the collection // // pTargetFormats = format collection's interface pointer // hwndListBox = listbox window handle // void BuildTargetFormatList(IltmmTargetFormats* pTargetFormats, HWND hwndListBox) { long i; long count; int selected = -1; // reset the listbox contents SendMessage(hwndListBox, LB_RESETCONTENT, 0, 0); // get the collection's item count pTargetFormats->get_Count(&count); for(i = 0; i < count; i++) { IltmmTargetFormat* pTargetFormat; BSTR bstr; TCHAR sz[256]; int index; VARIANT_BOOL f; // retrieve collection item pTargetFormats->Item(i, &pTargetFormat); // get displayable name pTargetFormat->get_Name(&bstr); // capture from unicode _stprintf(sz, _T("%ls"), bstr); // free name SysFreeString(bstr); // add the name to the listbox index = SendMessage(hwndListBox, LB_ADDSTRING, 0, (LPARAM) (LPCTSTR) sz); // associate the listbox item with the collection item index SendMessage(hwndListBox, LB_SETITEMDATA, index, i); // remember this listbox item, if it is selected in the collection pTargetFormat->get_Selected(&f); if(f) selected = i; // free the collection item pTargetFormat->Release(); } // select the appropriate listbox item for(i = 0; i < count; i++) { if(selected == (long) SendMessage(hwndListBox, LB_GETITEMDATA, i, 0)) { SendMessage(hwndListBox, LB_SETCURSEL, i, 0); break; } } } // // TargetFormatSelectionChanged // called to reflect changes in the listbox selection // // pTargetFormats = format collection's interface pointer // hwndListBox = listbox window handle // void TargetFormatSelectionChanged(IltmmTargetFormats* pTargetFormats, HWND hwndListBox) { int index; long item; int i; int count; HRESULT hr; // get the index of current listbox selection index = (int) SendMessage(hwndListBox, LB_GETCURSEL, 0, 0); if(index < 0) { // clear selection pTargetFormats->put_Selection(-1); } else { // get the collection item index item = (long) SendMessage(hwndListBox, LB_GETITEMDATA, index, 0); // select the item #ifdef _DEBUG { IltmmTargetFormat* pTargetFormat; pTargetFormats->Item(item, &pTargetFormat); hr = pTargetFormat->put_Selected(VARIANT_TRUE); pTargetFormat->Release(); } #else hr = pTargetFormats->put_Selection(item); #endif // if new selection failed, we need to force the listbox to match the actual selection if(FAILED(hr)) { // get the real selection pTargetFormats->get_Selection(&item); // find the matching listbox item count = (int) SendMessage(hwndListBox, LB_GETCOUNT, 0, 0); for(i = 0; i < count; i++) { if(item == (long) SendMessage(hwndListBox, LB_GETITEMDATA, i, 0)) { SendMessage(hwndListBox, LB_SETCURSEL, i, 0); break; } } } } #ifdef _DEBUG { long item; pTargetFormats->get_Selection(&item); if(item >= 0) { IltmmTargetFormat* pTargetFormat; TCHAR sz[2048]; LPTSTR p; VARIANT_BOOL b; BSTR bstr; sz[0] = _T('\0'); p = sz; pTargetFormats->Item(item, &pTargetFormat); pTargetFormat->get_AudioCompressor(&bstr); p += _stprintf(p, _T("AComp = %ls"), bstr); SysFreeString(bstr); pTargetFormat->get_VideoCompressor(&bstr); p += _stprintf(p, _T(", VComp = %ls"), bstr); SysFreeString(bstr); pTargetFormat->get_AVMux(&bstr); p += _stprintf(p, _T(", AVMux = %ls"), bstr); SysFreeString(bstr); pTargetFormat->get_Mux(&bstr); p += _stprintf(p, _T(", Mux = %ls"), bstr); SysFreeString(bstr); pTargetFormat->get_SinkSubType(&bstr); p += _stprintf(p, _T(", SubType = %ls"), bstr); SysFreeString(bstr); pTargetFormat->get_Sink(&bstr); p += _stprintf(p, _T(", Sink = %ls"), bstr); SysFreeString(bstr); pTargetFormat->get_ReadOnly(&b); p += _stprintf(p, _T(", ReadOnly = %s"), b != 0 ? _T("Yes") : _T("No")); pTargetFormat->Release(); MessageBox(NULL, sz, _T("Target Format"), MB_OK); } } #endif } // // AddCustomTargetFormats // called to append custom target formats // // pTargetFormats = format collection's interface pointer // void AddCustomTargetFormats(IltmmTargetFormats* pTargetFormats) { BSTR bstr; long index; IltmmTargetFormat* pTargetFormat; // remove all custom formats #ifdef _DEBUG pTargetFormats->get_Count(&index); pTargetFormats->Remove(index - 1); #else pTargetFormats->RemoveAll(); #endif bstr = SysAllocString(L"CUSTOM FORMAT 1"); pTargetFormats->Add(bstr, -1); pTargetFormats->Find(bstr, &index); SysFreeString(bstr); pTargetFormats->Item(index, &pTargetFormat); // assign an optional audio compressor // this case: MP3 bstr = SysAllocString(L"@device:cm:{33D9A761-90C8-11D0-BD43-00A0C911CE86}\\85MPEG Layer-3"); pTargetFormat->put_AudioCompressor(bstr); SysFreeString(bstr); // assign an optional video compressor // this case: LEAD MCMP bstr = SysAllocString(L"@device:sw:{33D9A760-90C8-11D0-BD43-00A0C911CE86}\\LEAD MCMP/MJPEG Codec (2.0)"); pTargetFormat->put_VideoCompressor(bstr); SysFreeString(bstr); // assign an optional AVMux compressor // this case: no premux bstr = SysAllocString(L""); pTargetFormat->put_AVMux(bstr); SysFreeString(bstr); // assign the required Mux // this case: AVI bstr = SysAllocString(L"@device:sw:{083863F1-70DE-11D0-BD40-00A0C911CE86}\\{E2510970-F137-11CE-8B67-00AA00A3F1A6}"); pTargetFormat->put_Mux(bstr); SysFreeString(bstr); // assign the optional SinkSubType // this case: MEDIASUBTYPE_Avi bstr = SysAllocString(L"{E436EB88-524F-11CE-9F53-0020AF0BA770}"); pTargetFormat->put_SinkSubType(bstr); SysFreeString(bstr); // assign an optional Sink // this case: default bstr = SysAllocString(L""); pTargetFormat->put_Sink(bstr); SysFreeString(bstr); pTargetFormat->Release(); } // // TargetFormatDlgProc // selects object formats // BOOL CALLBACK TargetFormatDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) { IltmmTargetFormats* pTargetFormats; switch (msg) { case WM_INITDIALOG: // initialize the target format listbox g_pCapture->get_TargetFormats(&pTargetFormats); AddCustomTargetFormats(pTargetFormats); BuildTargetFormatList(pTargetFormats, GetDlgItem(hwnd, IDC_TARGETFORMATS)); pTargetFormats->Release(); return TRUE; break; case WM_COMMAND: switch(LOWORD(wParam)) { case IDC_TARGETFORMATS: if(HIWORD(wParam) == LBN_SELCHANGE) { // select the target format g_pCapture->get_TargetFormats(&pTargetFormats); TargetFormatSelectionChanged(pTargetFormats, GetDlgItem(hwnd, IDC_TARGETFORMATS)); pTargetFormats->Release(); } break; case IDOK: EndDialog(hwnd, IDOK); return TRUE; break; } break; } return FALSE; } int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { HRESULT hr; g_hInstance = hInstance; // initialize COM library hr = CoInitialize(NULL); if(FAILED(hr)) goto error; // create the capture object hr = CoCreateInstance(CLSID_ltmmCapture, NULL, CLSCTX_INPROC_SERVER, IID_IltmmCapture, (void**) &g_pCapture); if(FAILED(hr)) goto error; DialogBox(g_hInstance, (LPCTSTR)IDD_TARGETFORMATDLG, NULL, TargetFormatDlgProc); error: // cleanup if(g_pCapture) g_pCapture->Release(); CoUninitialize(); return 0; }