The following code demonstrates how to enumerate, add, and select ltmmCapture object target formats:
#ifndef COBJMACROS
#define COBJMACROS
#endif
#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
IltmmTargetFormats_get_Count (pTargetFormats, &count);
for(i = 0; i < count; i++)
{
IltmmTargetFormat* pTargetFormat;
BSTR bstr;
TCHAR sz[256];
int index;
VARIANT_BOOL f;
// retrieve collection item
IltmmTargetFormats_Item (pTargetFormats, i, &pTargetFormat);
// get displayable name
IltmmTargetFormat_get_Name(pTargetFormat, &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
IltmmTargetFormat_get_Selected(pTargetFormat, &f);
if(f)
selected = i;
// free the collection item
IUnknown_Release(pTargetFormat);
}
// 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
IltmmTargetFormats_put_Selection(pTargetFormats, -1);
}
else
{
// get the collection item index
item = (long) SendMessage(hwndListBox, LB_GETITEMDATA, index, 0);
// select the item
#ifdef _DEBUG
{
IltmmTargetFormat* pTargetFormat;
IltmmTargetFormats_Item (pTargetFormats, item, &pTargetFormat);
hr = IltmmTargetFormat_put_Selected(pTargetFormat, VARIANT_TRUE);
IUnknown_Release(pTargetFormat);
}
#else
hr = IltmmTargetFormats_put_Selection(pTargetFormats, item);
#endif
// if new selection failed, we need to force the listbox to match the actual selection
if(FAILED(hr))
{
// get the real selection
IltmmTargetFormats_get_Selection (pTargetFormats, &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;
IltmmTargetFormats_get_Selection (pTargetFormats, &item);
if(item >= 0)
{
IltmmTargetFormat* pTargetFormat;
TCHAR sz[2048];
LPTSTR p;
VARIANT_BOOL b;
BSTR bstr;
sz[0] = _T('\0');
p = sz;
IltmmTargetFormats_Item (pTargetFormats, item, &pTargetFormat);
IltmmTargetFormat_get_AudioCompressor(pTargetFormat, &bstr);
p += _stprintf(p, _T("AComp = %ls"), bstr);
SysFreeString(bstr);
IltmmTargetFormat_get_VideoCompressor(pTargetFormat, &bstr);
p += _stprintf(p, _T(", VComp = %ls"), bstr);
SysFreeString(bstr);
IltmmTargetFormat_get_AVMux(pTargetFormat, &bstr);
p += _stprintf(p, _T(", AVMux = %ls"), bstr);
SysFreeString(bstr);
IltmmTargetFormat_get_Mux(pTargetFormat, &bstr);
p += _stprintf(p, _T(", Mux = %ls"), bstr);
SysFreeString(bstr);
IltmmTargetFormat_get_SinkSubType (pTargetFormat, &bstr);
p += _stprintf(p, _T(", SubType = %ls"), bstr);
SysFreeString(bstr);
IltmmTargetFormat_get_Sink(pTargetFormat, &bstr);
p += _stprintf(p, _T(", Sink = %ls"), bstr);
SysFreeString(bstr);
IltmmTargetFormat_get_ReadOnly(pTargetFormat, &b);
p += _stprintf(p, _T(", ReadOnly = %s"), b != 0 ? _T("Yes") : _T("No"));
IUnknown_Release(pTargetFormat);
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
IltmmTargetFormats_get_Count (pTargetFormats, &index);
IltmmTargetFormats_Remove(pTargetFormats, index - 1);
#else
IltmmTargetFormats_RemoveAll(pTargetFormats);
#endif
bstr = SysAllocString(L"CUSTOM FORMAT 1");
IltmmTargetFormats_Add(pTargetFormats, bstr, -1);
IltmmTargetFormats_Find(pTargetFormats, bstr, &index);
SysFreeString(bstr);
IltmmTargetFormats_Item(pTargetFormats, index, &pTargetFormat);
// assign an optional audio compressor
// this case: MP3
bstr = SysAllocString(L"@device:cm:{33D9A761-90C8-11D0-BD43-00A0C911CE86}\\85MPEG Layer-3");
IltmmTargetFormat_put_AudioCompressor (pTargetFormat, 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)");
IltmmTargetFormat_put_VideoCompressor (pTargetFormat, bstr);
SysFreeString(bstr);
// assign an optional AVMux compressor
// this case: no premux
bstr = SysAllocString(L"");
IltmmTargetFormat_put_AVMux(pTargetFormat, 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}");
IltmmTargetFormat_put_Mux(pTargetFormat, bstr);
SysFreeString(bstr);
// assign the optional SinkSubType
// this case: MEDIASUBTYPE_Avi
bstr = SysAllocString(L"{E436EB88-524F-11CE-9F53-0020AF0BA770}");
IltmmTargetFormat_put_SinkSubType(pTargetFormat, bstr);
SysFreeString(bstr);
// assign an optional Sink
// this case: default
bstr = SysAllocString(L"");
IltmmTargetFormat_put_Sink(pTargetFormat, bstr);
SysFreeString(bstr);
IUnknown_Release(pTargetFormat);
}
//
// TargetFormatDlgProc
// selects object formats
//
BOOL CALLBACK TargetFormatDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
IltmmTargetFormats* pTargetFormats;
lParam = lParam ;
switch (msg)
{
case WM_INITDIALOG:
// initialize the target format listbox
IltmmCapture_get_TargetFormats(g_pCapture, &pTargetFormats);
AddCustomTargetFormats(pTargetFormats);
BuildTargetFormatList(pTargetFormats, GetDlgItem(hwnd, IDC_TARGETFORMATS));
IUnknown_Release(pTargetFormats);
return TRUE;
break;
case WM_COMMAND:
switch(LOWORD(wParam))
{
case IDC_TARGETFORMATS:
if(HIWORD(wParam) == LBN_SELCHANGE)
{
// select the target format
IltmmCapture_get_TargetFormats(g_pCapture, &pTargetFormats);
TargetFormatSelectionChanged(pTargetFormats, GetDlgItem(hwnd, IDC_TARGETFORMATS));
IUnknown_Release(pTargetFormats);
}
break;
case IDOK:
EndDialog(hwnd, IDOK);
return TRUE;
break;
}
break;
}
return FALSE;
}
void SelectingltmmCaptureObjectTargetFormats_Example ( HINSTANCE hInstance )
{
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)
IUnknown_Release(g_pCapture);
CoUninitialize();
}