Simple Media Player for C

// define helper macros for using interfaces under C 
#ifndef COBJMACROS 
   #define COBJMACROS 
#endif 
 
// include the LEAD Multimedia TOOLKIT header 
#include "ltmm.h" 
 
#include "resource.h" 
#include <tchar.h> 
#include <stdio.h> 
#include <math.h> 
 
 
#define SZ_WNDCLASS_PLAY _T("PLAY WNDCLASS") 
#define WM_PLAYNOTIFY (WM_USER + 1000)  
 
HINSTANCE g_hInstance;    // application instance handle 
HWND g_hwndPlay;      // video frame window 
IltmmPlay* g_pPlay;      // play object interface pointer 
int g_nPositionView;   // current position indicator view mode 
enum 
{ 
   POSITIONVIEW_TIME,  
   POSITIONVIEW_FRAME,  
   POSITIONVIEW_TRACKING 
}; 
 
 
// 
// SnapFrameToVideo 
// resizes the frame window to match the video width and height 
// 
void SnapFrameToVideo(void)  
{ 
   HWND hwnd;  
   RECT rcWindow, rcClient;  
   long cx, cy;  
 
   // get the frame window 
   IltmmPlay_get_VideoWindowFrame (g_pPlay, (long*) &hwnd);  
 
   // get the video dimensions 
   IltmmPlay_get_VideoWidth (g_pPlay, &cx);  
   IltmmPlay_get_VideoHeight (g_pPlay, &cy);  
 
   // adjust by the border dimensions 
   GetWindowRect(hwnd, &rcWindow);  
   GetClientRect(hwnd, &rcClient);  
   cx += ((rcWindow.right - rcWindow.left) - (rcClient.right - rcClient.left));  
   cy += ((rcWindow.bottom - rcWindow.top) - (rcClient.bottom - rcClient.top));  
 
   // resize the window 
   SetWindowPos(hwnd, NULL, 0, 0, cx, cy, SWP_NOMOVE | SWP_NOZORDER);  
} 
 
// 
// FreeSource 
// resets source and frees associated resources 
// 
void FreeSource(void)  
{ 
   long type;  
   VARIANT var;  
   HGLOBAL hglobal;  
 
   IltmmPlay_get_SourceType (g_pPlay, &type);  
   if(type == ltmmPlay_Source_Array)  
   { 
      IltmmPlay_get_SourceArray(g_pPlay, &var);  
      IltmmPlay_ResetSource(g_pPlay);  
      VariantClear(&var);  
   } 
   else if(type == ltmmPlay_Source_HGlobal)  
   { 
      IltmmPlay_get_SourceHGlobal (g_pPlay, (long*) &hglobal);  
      IltmmPlay_ResetSource(g_pPlay);  
      GlobalFree(hglobal);  
   } 
   else 
   { 
      IltmmPlay_ResetSource(g_pPlay);  
   } 
 
} 
 
// 
// SetSourceArray 
// preloads a SAFEARRAY with media data and assigns it to the play object 
// 
void SetSourceArray(void)  
 
{ 
   HRESULT hr;  
   HANDLE hfile;    
   DWORD size, cb;  
   void* buffer;  
   VARIANT var;  
   SAFEARRAY* psaSource;  
 
   // open the source file 
   hfile = CreateFile(MAKE_MEDIA_PATH("source.avi"), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);  
   if(hfile == INVALID_HANDLE_VALUE)  
      return;  
 
   // allocate same-sized SAFEARRAY 
   size = GetFileSize(hfile, NULL);  
 
   psaSource = SafeArrayCreateVector(VT_UI1, 0, size);  
   if(!psaSource)  
   { 
      CloseHandle(hfile);  
      return;  
   } 
 
   // read entire source into array 
   SafeArrayAccessData(psaSource, (void**) &buffer);  
   if(!ReadFile(hfile, buffer, size, &cb, NULL) || cb != size)  
   { 
      SafeArrayUnaccessData(psaSource);  
      CloseHandle(hfile);  
      SafeArrayDestroy(psaSource);  
      return;  
   } 
   SafeArrayUnaccessData(psaSource);  
 
   // close file 
   CloseHandle(hfile);  
 
   // assign the source array 
   VariantInit(&var);  
   V_VT(&var) = (VT_ARRAY | VT_UI1);  
   V_ARRAY(&var) = psaSource;  
 
   hr = IltmmPlay_put_SourceArray (g_pPlay, var);  
   if(FAILED(hr))  
   { 
      SafeArrayDestroy(psaSource);  
      return;  
   } 
} 
 
// 
// SetSourceArray 
// preloads global memory with media data and assigns it to the play object 
// 
void SetSourceHGlobal(void)  
{ 
   HRESULT hr;  
   HANDLE hfile;    
   DWORD size, cb;  
   void* buffer;  
   HGLOBAL hglobal;  
 
   // open the source file 
   hfile = CreateFile(MAKE_MEDIA_PATH("source.avi"), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);  
   if(hfile == INVALID_HANDLE_VALUE)  
      return;  
 
   // allocate same-sized global memory 
   size = GetFileSize(hfile, NULL);  
 
   hglobal = GlobalAlloc(GMEM_MOVEABLE, size);  
   if(!hglobal)  
   { 
      CloseHandle(hfile);  
      return;  
   } 
 
   // read entire source into memory 
   buffer = GlobalLock(hglobal);  
   if(!ReadFile(hfile, buffer, size, &cb, NULL) || cb != size)  
   { 
      GlobalUnlock(hglobal);  
      CloseHandle(hfile);  
      GlobalFree(hglobal);  
      return;  
   } 
   GlobalUnlock(hglobal);  
 
   // close file 
   CloseHandle(hfile);  
 
 
   hr = IltmmPlay_put_SourceHGlobal(g_pPlay, (long) hglobal);  
   if(FAILED(hr))  
   { 
      GlobalFree(hglobal);  
      return;  
   } 
} 
 
// 
// PlayWndProc 
// video frame window procedure 
// 
LRESULT CALLBACK PlayWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)  
{ 
   BSTR bstr;  
   VARIANT_BOOL f;  
   long l;  
   TCHAR sz[2048];  
   LPTSTR p;  
   double d;  
   HRESULT hr;  
   ltmmSizeMode sm;  
   long x, y, cx, cy;  
   RECT rc;  
   POINT pt;  
 
   switch (message)  
   { 
   case WM_CREATE:  
      g_hwndPlay = hwnd;  
      // window is the video window frame 
      IltmmPlay_put_VideoWindowFrame (g_pPlay, (long) hwnd);  
 
      // want notification messages as well 
      IltmmPlay_SetNotifyWindow (g_pPlay, (long) hwnd, WM_PLAYNOTIFY);  
 
      // make sure we start playing immediately 
 
      IltmmPlay_put_AutoStart (g_pPlay, VARIANT_TRUE);  
 
      // set the source file 
      bstr = SysAllocString((OLECHAR*)MAKE_MEDIA_PATH("source.avi")); 
      IltmmPlay_put_SourceFile (g_pPlay, bstr);  
      SysFreeString(bstr);  
 
      SnapFrameToVideo(); 
 
      return 0;  
      break;  
   case WM_INITMENUPOPUP:  
      if(GetSubMenu(GetMenu(hwnd), 0) == (HMENU)wParam)  
      { 
         // enable menu items based on the play object state 
         IltmmPlay_get_State (g_pPlay, &l);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PLAY, (l == ltmmPlay_State_Paused || l == ltmmPlay_State_Stopped) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PAUSE, (l == ltmmPlay_State_Running) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_STOP, (l == ltmmPlay_State_Running || l == ltmmPlay_State_Paused) ? MF_ENABLED : MF_GRAYED);  
 
         // enable menu items based on seeking capabilities 
         IltmmPlay_CheckSeekingCapabilities (g_pPlay, ltmmPlay_Seeking_Forward | ltmmPlay_Seeking_Backward | ltmmPlay_Seeking_FrameForward | ltmmPlay_Seeking_FrameBackward, &l);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_SEEKSTART, (l & ltmmPlay_Seeking_Backward) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_SEEKEND, (l & ltmmPlay_Seeking_Forward) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_NEXTFRAME, (l & ltmmPlay_Seeking_FrameForward) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PREVIOUSFRAME, (l & ltmmPlay_Seeking_FrameBackward) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_SEEKSELECTIONSTART, (l & (ltmmPlay_Seeking_Forward | ltmmPlay_Seeking_Backward)) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_SEEKSELECTIONEND, (l & (ltmmPlay_Seeking_Forward | ltmmPlay_Seeking_Backward)) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_LASTFRAME, (l & ltmmPlay_Seeking_FrameForward) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_FIRSTFRAME, (l & ltmmPlay_Seeking_FrameBackward) ? MF_ENABLED : MF_GRAYED);  
 
         EnableMenuItem((HMENU) wParam, ID_CONTROL_STEPFORWARD1SEC, (l & ltmmPlay_Seeking_Forward) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_STEPFORWARD10, (l & ltmmPlay_Seeking_Forward) ? MF_ENABLED : MF_GRAYED);  
 
         // check the current speed 
         IltmmPlay_get_Rate (g_pPlay, &d);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_HALFSPEED, (fabs(d - 0.5) < 0.1) ? MF_CHECKED : MF_UNCHECKED);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_NORMALSPEED, (fabs(d - 1.0) < 0.1) ? MF_CHECKED : MF_UNCHECKED);  
 
         // check the current video size mode 
         IltmmPlay_get_VideoWindowSizeMode (g_pPlay, &sm);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_FITTOWINDOW, (sm == ltmmFit) ? MF_CHECKED : MF_UNCHECKED);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_STRETCHTOWINDOW, (sm == ltmmStretch) ? MF_CHECKED : MF_UNCHECKED);  
 
         // enable volume menu items 
         IltmmPlay_get_Volume (g_pPlay, &l);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_INCREASEVOLUME, (l < 0) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_DECREASEVOLUME, (l > -10000) ? MF_ENABLED : MF_GRAYED);  
 
         // enable balance menu items 
         IltmmPlay_get_Balance (g_pPlay, &l);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PANRIGHT, (l < 10000) ? MF_ENABLED : MF_GRAYED);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PANLEFT, (l > -10000) ? MF_ENABLED : MF_GRAYED);  
 
 
         // check mute 
         IltmmPlay_get_Mute (g_pPlay, &f);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_MUTE, f ? MF_CHECKED : MF_UNCHECKED);  
 
         // check auto rewind 
         IltmmPlay_get_AutoRewind (g_pPlay, &f);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_AUTOREWIND, f ? MF_CHECKED : MF_UNCHECKED);  
 
         // check loop 
         IltmmPlay_get_PlayCount (g_pPlay, &l);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_LOOP, (l == 0) ? MF_CHECKED : MF_UNCHECKED);  
 
         // enable processors 
         IltmmPlay_HasDialog(g_pPlay, ltmmPlay_Dlg_VideoProcessors, &f);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PROCESSORS_VIDEO, f ? MF_ENABLED : MF_GRAYED);  
         IltmmPlay_HasDialog(g_pPlay, ltmmPlay_Dlg_AudioProcessors, &f);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PROCESSORS_AUDIO, f ? MF_ENABLED : MF_GRAYED);  
 
         // check source 
         IltmmPlay_get_SourceType (g_pPlay, &l);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_SOURCE_FILE, (l == ltmmPlay_Source_File) ? MF_CHECKED : MF_UNCHECKED);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_SOURCE_ARRAY, (l == ltmmPlay_Source_Array) ? MF_CHECKED : MF_UNCHECKED);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_SOURCE_HGLOBAL, (l == ltmmPlay_Source_HGlobal) ? MF_CHECKED : MF_UNCHECKED);  
 
         IltmmPlay_get_AutoStart (g_pPlay, &f);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_AUTOSTART, f ? MF_CHECKED : MF_UNCHECKED);  
 
         // check position view 
         CheckMenuItem((HMENU) wParam, ID_CONTROL_POSITIONVIEW_FRAME, (g_nPositionView == POSITIONVIEW_FRAME) ? MF_CHECKED : MF_UNCHECKED);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_POSITIONVIEW_TIME, (g_nPositionView == POSITIONVIEW_TIME) ? MF_CHECKED : MF_UNCHECKED);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_POSITIONVIEW_TRACKING, (g_nPositionView == POSITIONVIEW_TRACKING) ? MF_CHECKED : MF_UNCHECKED);  
 
      } 
      break;  
   case WM_PLAYNOTIFY:  
      switch(wParam)  
      { 
      case ltmmPlay_Notify_TrackingSelectionChanged:  
         break;  
      case ltmmPlay_Notify_TrackingPositionChanged:  
         p = sz;  
 
         *p = _T('\0');  
 
         if(g_nPositionView == POSITIONVIEW_TRACKING)   // tracking position based 
         { 
            // display current tracking position 
            hr = IltmmPlay_get_CurrentTrackingPosition (g_pPlay, &l);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Trk. Pos.: %d"), l);  
            }    
 
            // display current tracking selection start 
            hr = IltmmPlay_get_TrackingSelectionStart(g_pPlay, &l);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Trk. Start: %d"), l);  
            } 
 
            // display current tracking selection end 
            hr= IltmmPlay_get_TrackingSelectionEnd (g_pPlay, &l);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Trk. End: %d"), l);  
            } 
         } 
         else if(g_nPositionView == POSITIONVIEW_FRAME)   // frame based 
         { 
            // display current frame position 
            hr = IltmmPlay_get_CurrentFramePosition (g_pPlay, &l);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Frame: %d"), l + 1);  
            } 
 
            // display total number of frames 
            hr = IltmmPlay_get_FrameDuration (g_pPlay, &l);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Total Frames: %d"), l);  
            } 
 
 
         } 
         else // time based 
         { 
            // display the current position 
            hr = IltmmPlay_get_CurrentPosition (g_pPlay, &d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Position: %f"), d);  
            }    
 
            // display the total duration 
            hr = IltmmPlay_get_Duration (g_pPlay, &d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Duration: %f"), d);  
            } 
 
            // display current selection start 
            hr = IltmmPlay_get_SelectionStart (g_pPlay, &d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Start: %f"), d);  
            } 
 
            // display current selection end 
            hr = IltmmPlay_get_SelectionEnd (g_pPlay, &d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("End: %f"), d);  
            } 
 
         } 
         SetWindowText(hwnd, sz);  
         break;  
      case ltmmPlay_Notify_StateChanged:  
         switch(LOWORD(lParam))  
         { 
         case ltmmPlay_State_NotReady:  
            _stprintf(sz, _T("Not Ready")); 
            SetWindowText(hwnd, sz);  
            break;  
         case ltmmPlay_State_Stopped:  
            // uncomment the following line to view the graph in DirectShow GraphEdit 
            // IltmmPlay_EditGraph(g_pPlay); 
            IltmmPlay_get_SourceType (g_pPlay, &l);  
            if(l == ltmmPlay_Source_Array)  
            { 
               _stprintf(sz, _T("Stopped - [array]"));  
            } 
            else if(l == ltmmPlay_Source_HGlobal)  
            { 
               _stprintf(sz, _T("Stopped - [hglobal]"));  
            } 
            else 
            { 
               IltmmPlay_get_SourceFile(g_pPlay, &bstr);  
               _stprintf(sz, _T("Stopped - [%ls]"), bstr);  
               SysFreeString(bstr);  
            } 
            SetWindowText(hwnd, sz);  
            break;  
         case ltmmPlay_State_Paused:  
            IltmmPlay_get_SourceType (g_pPlay, &l);  
            if(l == ltmmPlay_Source_Array)  
            { 
               _stprintf(sz, _T("Paused - [array]"));  
            } 
            else if(l == ltmmPlay_Source_HGlobal)  
            { 
               _stprintf(sz, _T("Paused - [hglobal]"));  
            } 
            else 
            { 
               IltmmPlay_get_SourceFile (g_pPlay, &bstr);  
               _stprintf(sz, _T("Paused - [%ls]"), bstr);  
               SysFreeString(bstr);  
            } 
            SetWindowText(hwnd, sz);  
            break;  
         case ltmmPlay_State_Running:  
            _stprintf(sz, _T("Playing")); 
            SetWindowText(hwnd, sz);  
            break;  
         } 
         break;  
      case ltmmPlay_Notify_Error:  
         _stprintf(sz, _T("Error 0x%.8X. Playback stopped."), lParam);  
         MessageBox(hwnd, sz, _T("Play"), MB_ICONEXCLAMATION | MB_OK);  
         break;  
      } 
      return 0;  
      break;  
   case WM_KEYDOWN:  
      if(wParam == VK_ESCAPE)  
      { 
         // if fullscreen mode then exit it 
         IltmmPlay_get_FullScreenMode (g_pPlay, &f);  
         if(f)  
         { 
            IltmmPlay_put_FullScreenMode (g_pPlay, VARIANT_FALSE);  
            return 0;  
         } 
      } 
      break;  
   case WM_DESTROY:  
      FreeSource(); 
      // no more notifications 
      IltmmPlay_SetNotifyWindow (g_pPlay, (long) NULL, 0);  
      PostQuitMessage(0);  
      break;  
   case WM_COMMAND:  
      switch(LOWORD(wParam))  
      { 
      case ID_CONTROL_POSITIONVIEW_TIME:  
         g_nPositionView = POSITIONVIEW_TIME;  
         break;  
      case ID_CONTROL_POSITIONVIEW_FRAME:  
         g_nPositionView = POSITIONVIEW_FRAME;  
         break;  
      case ID_CONTROL_POSITIONVIEW_TRACKING:  
         g_nPositionView = POSITIONVIEW_TRACKING;  
         break;  
      case ID_CONTROL_AUTOSTART:  
         // toggle auto start 
         IltmmPlay_get_AutoStart (g_pPlay, &f);    
         IltmmPlay_put_AutoStart (g_pPlay, f ? VARIANT_FALSE : VARIANT_TRUE);  
         return 0;  
         break;  
      case ID_CONTROL_PLAY:  
         // play file 
         IltmmPlay_Run (g_pPlay);    
         return 0;  
         break;  
      case ID_CONTROL_PAUSE:  
         // pause playback 
         IltmmPlay_Pause (g_pPlay);    
         return 0;  
         break;  
      case ID_CONTROL_STOP:  
         // stop playback 
         IltmmPlay_Stop (g_pPlay);    
         return 0;  
         break;  
      case ID_CONTROL_HALFSPEED:  
         // set to half the normal playback speed 
         IltmmPlay_put_Rate (g_pPlay, 0.5);  
         return 0;  
         break;  
      case ID_CONTROL_NORMALSPEED:  
         // set to normal speed 
         IltmmPlay_put_Rate (g_pPlay, 1.0);  
         return 0;  
         break;  
      case ID_CONTROL_SEEKSTART:  
         // seek to file start 
         IltmmPlay_SeekStart(g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_SEEKEND:  
         // seek to file end 
         IltmmPlay_SeekEnd (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_SEEKSELECTIONSTART:  
         // seek to the start of the current selection 
         IltmmPlay_SeekSelectionStart (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_SEEKSELECTIONEND:  
         // seek to the end of the current selection 
         IltmmPlay_SeekSelectionEnd (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_SETSELECTIONSTART:  
         // set the start of the selection to the current position 
         IltmmPlay_MarkSelectionStart (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_SETSELECTIONEND:  
         // set the end of the selection to the current position 
         IltmmPlay_MarkSelectionEnd (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_CLEARSELECTION:  
         // clear the current selection 
         IltmmPlay_get_Duration(g_pPlay, &d);       
         IltmmPlay_put_SelectionStart (g_pPlay, 0.0);  
         IltmmPlay_put_SelectionEnd (g_pPlay, d);  
         return 0;  
         break;  
      case ID_CONTROL_NEXTFRAME:  
         // goto the next frame 
         IltmmPlay_NextFrame (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_PREVIOUSFRAME:  
         // goto the previous frame 
         IltmmPlay_PreviousFrame (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_FIRSTFRAME:  
         // goto to the first frame 
         IltmmPlay_put_CurrentFramePosition (g_pPlay, 0);  
         return 0;  
         break;  
      case ID_CONTROL_LASTFRAME:  
         // goto to the last frame 
         IltmmPlay_get_FrameDuration (g_pPlay, &l);  
         IltmmPlay_put_CurrentFramePosition (g_pPlay, l - 1);  
         return 0;  
         break;  
      case ID_CONTROL_STEPFORWARD1SEC:  
         // step forward 1 second 
         IltmmPlay_get_CurrentPosition (g_pPlay, &d);  
         IltmmPlay_put_CurrentPosition (g_pPlay, d + 1.0);  
         return 0;  
         break;  
      case ID_CONTROL_STEPFORWARD10:  
         // step forward 10% 
         IltmmPlay_get_CurrentTrackingPosition (g_pPlay, &l);  
         IltmmPlay_put_CurrentTrackingPosition(g_pPlay, l + 1000);  
         return 0;  
         break;  
      case ID_CONTROL_FITTOWINDOW:  
         // fit the video to the window 
         IltmmPlay_put_VideoWindowSizeMode (g_pPlay, ltmmFit);  
         return 0;  
         break;  
      case ID_CONTROL_STRETCHTOWINDOW:  
         // stretch the video to the window 
         IltmmPlay_put_VideoWindowSizeMode (g_pPlay, ltmmStretch);  
         return 0;  
         break;  
      case ID_CONTROL_MUTE:  
         // toggle mute 
         IltmmPlay_get_Mute (g_pPlay, &f);  
         IltmmPlay_put_Mute (g_pPlay, f ? VARIANT_FALSE : VARIANT_TRUE);  
         return 0;  
         break;  
      case ID_CONTROL_INCREASEVOLUME:  
         // increase the volume 
         IltmmPlay_get_Volume (g_pPlay, &l);  
         IltmmPlay_put_Volume (g_pPlay, min(0, l + 300));  
         return 0;  
         break;  
      case ID_CONTROL_DECREASEVOLUME:  
         // decrease the volume 
         IltmmPlay_get_Volume (g_pPlay, &l);  
         IltmmPlay_put_Volume (g_pPlay, max(-10000, l - 300));  
         return 0;  
         break;  
      case ID_CONTROL_PANRIGHT:  
         // pan balance to the right 
         IltmmPlay_get_Balance (g_pPlay, &l);  
         IltmmPlay_put_Balance(g_pPlay, min(10000, l + 300));  
         return 0;  
         break;  
      case ID_CONTROL_PANLEFT:  
         // pan balance to the left 
         IltmmPlay_get_Balance (g_pPlay, &l);  
         IltmmPlay_put_Balance (g_pPlay, max(-10000, l - 300));  
         return 0;  
         break;  
      case ID_CONTROL_LOOP:  
         // toggle looping 
         IltmmPlay_get_PlayCount(g_pPlay, &l);  
         IltmmPlay_put_PlayCount (g_pPlay, l ? 0 : 1);  
         return 0;  
         break;  
      case ID_CONTROL_FULLSCREEN:  
         // toggle fullscreen mode 
         IltmmPlay_ToggleFullScreenMode (g_pPlay);  
         return 0;  
         break;  
      case ID_CONTROL_AUTOREWIND:  
         // toggle auto rewind 
         IltmmPlay_get_AutoRewind (g_pPlay, &f);  
         IltmmPlay_put_AutoRewind (g_pPlay, f ? VARIANT_FALSE : VARIANT_TRUE);  
         return 0;  
         break;  
      case ID_CONTROL_PROCESSORS_VIDEO:  
         // invoke video processor dialog box 
         IltmmPlay_ShowDialog (g_pPlay, ltmmPlay_Dlg_VideoProcessors, (long) hwnd);  
         return 0;  
         break;  
      case ID_CONTROL_PROCESSORS_AUDIO:  
         // invoke audio processor dialog box 
         IltmmPlay_ShowDialog (g_pPlay, ltmmPlay_Dlg_AudioProcessors, (long) hwnd);  
         return 0;  
         break;  
      case ID_CONTROL_SOURCE_FILE:  
         // set the source file 
         FreeSource(); 
         bstr = SysAllocString((OLECHAR*)MAKE_MEDIA_PATH("source.avi")); 
         IltmmPlay_put_SourceFile (g_pPlay, bstr);  
         SysFreeString(bstr);  
         SnapFrameToVideo(); 
         return 0;  
         break;  
      case ID_CONTROL_SOURCE_ARRAY:  
         // set the source array 
         FreeSource(); 
         SetSourceArray(); 
         SnapFrameToVideo(); 
         return 0;  
         break;  
      case ID_CONTROL_SOURCE_HGLOBAL:  
         // set the source hglobal 
         FreeSource(); 
         SetSourceHGlobal(); 
         SnapFrameToVideo(); 
         return 0;  
         break;  
      case ID_CONTROL_MEDIAINFORMATION:  
         // display available media information          
         p = sz;  
 
         IltmmPlay_get_Title (g_pPlay, &bstr);  
         p += _stprintf(p, _T("Title = '%ls'"), bstr ? bstr : L""); 
         SysFreeString(bstr);  
 
         IltmmPlay_get_Author (g_pPlay, &bstr);  
         p += _stprintf(p, _T(", Author = '%ls'"), bstr ? bstr : L""); 
         SysFreeString(bstr);  
 
         IltmmPlay_get_Copyright (g_pPlay, &bstr);  
         p += _stprintf(p, _T(", Copyright = '%ls'"), bstr ? bstr : L""); 
         SysFreeString(bstr);  
 
         IltmmPlay_get_Description (g_pPlay, &bstr);  
         p += _stprintf(p, _T(", Description = '%ls'"), bstr ? bstr : L""); 
         SysFreeString(bstr);  
 
         IltmmPlay_get_Rating (g_pPlay, &bstr);  
         p += _stprintf(p, _T(", Rating = '%ls'"), bstr ? bstr : L""); 
         SysFreeString(bstr);  
 
         MessageBox(hwnd, sz, _T("Media Information"), MB_OK);  
 
         return 0;  
         break;  
      } 
      break;  
   case WM_LBUTTONDOWN:  
      // perform play/pause if the user clicks in the video window 
      IltmmPlay_get_VideoWindowLeft (g_pPlay, &x);  
      IltmmPlay_get_VideoWindowTop (g_pPlay, &y);  
      IltmmPlay_get_VideoWindowWidth (g_pPlay, &cx);  
      IltmmPlay_get_VideoWindowHeight (g_pPlay, &cy);  
      SetRect(&rc, x, y, x + cx, y + cy);  
      pt.x = (short) LOWORD(lParam);  
      pt.y = (short) HIWORD(lParam);  
      if(PtInRect(&rc, pt))  
      { 
         IltmmPlay_get_State (g_pPlay, &l);  
 
         if(l == ltmmPlay_State_Stopped || l == ltmmPlay_State_Paused)  
            IltmmPlay_Run (g_pPlay);  
         else if(l == ltmmPlay_State_Running)  
            IltmmPlay_Pause (g_pPlay);  
      } 
      return 0;  
      break;  
   } 
   return DefWindowProc(hwnd, message, wParam, lParam);  
} 
 
 
int APIENTRY WinMain(HINSTANCE hInstance,  
                     HINSTANCE hPrevInstance,  
                     LPSTR     lpCmdLine,  
                     int       nCmdShow)  
{ 
   MSG msg;  
   HRESULT hr;  
   WNDCLASSEX wcex;  
 
 
   hPrevInstance = hPrevInstance ; 
   lpCmdLine = lpCmdLine ; 
   nCmdShow  = nCmdShow ; 
 
   g_hInstance = hInstance;  
 
   // initialize COM library 
   hr = CoInitialize(NULL);  
   if(FAILED(hr))  
      goto error;  
 
 
   // register the video frame window class 
   wcex.cbSize = sizeof(WNDCLASSEX);  
   wcex.style = CS_HREDRAW | CS_VREDRAW;  
   wcex.lpfnWndProc = PlayWndProc;  
   wcex.cbClsExtra = 0;  
   wcex.cbWndExtra = 0;  
   wcex.hInstance = g_hInstance;  
   wcex.hIcon = NULL;  
   wcex.hCursor = LoadCursor(NULL, IDC_ARROW);  
   wcex.hbrBackground = (HBRUSH) (COLOR_APPWORKSPACE + 1);  
   wcex.lpszMenuName = (LPCSTR)IDR_MENU;  
   wcex.lpszClassName = SZ_WNDCLASS_PLAY;  
   wcex.hIconSm = NULL;  
 
   if(!RegisterClassEx(&wcex))  
      goto error;  
 
 
   // create the play object 
   hr = CoCreateInstance(&CLSID_ltmmPlay, NULL, CLSCTX_INPROC_SERVER, &IID_IltmmPlay, (void**) &g_pPlay);  
   if(FAILED(hr))  
      goto error;  
 
   // create the video frame window 
   if(!CreateWindow(SZ_WNDCLASS_PLAY, _T("Play"), WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,  
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, g_hInstance, NULL))  
      goto error;  
 
   ShowWindow(g_hwndPlay, nCmdShow);  
 
   UpdateWindow(g_hwndPlay);  
 
   // process until done 
   while (GetMessage(&msg, NULL, 0, 0))  
   { 
      TranslateMessage(&msg);  
      DispatchMessage(&msg);  
   } 
 
error:  
   if(g_pPlay)  
      IUnknown_Release(g_pPlay);  
 
   CoUninitialize(); 
 
   return 0;    
}