Simple Media Player for C++

#include "stdafx.h" 
 
// 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 
   g_pPlay->get_VideoWindowFrame ((long*) &hwnd);  
 
   // get the video dimensions 
   g_pPlay->get_VideoWidth (&cx);  
   g_pPlay->get_VideoHeight (&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;  
 
   g_pPlay->get_SourceType (&type);  
   if(type == ltmmPlay_Source_Array)  
   { 
      g_pPlay->get_SourceArray (&var);  
      g_pPlay->ResetSource (); 
      VariantClear(&var);  
   } 
   else if(type == ltmmPlay_Source_HGlobal)  
   { 
      g_pPlay->get_SourceHGlobal ((long*) &hglobal);  
      g_pPlay->ResetSource (); 
      GlobalFree(hglobal);  
   } 
   else 
   { 
      g_pPlay->ResetSource (); 
   } 
 
} 
 
// 
// 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(_T("c:\\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 = g_pPlay->put_SourceArray (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(_T("c:\\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 = g_pPlay->put_SourceHGlobal ((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 
      g_pPlay->put_VideoWindowFrame ((long) hwnd);  
 
      // want notification messages as well 
      g_pPlay->SetNotifyWindow ((long) hwnd, WM_PLAYNOTIFY);  
 
      // make sure we start playing immediately 
 
      g_pPlay->put_AutoStart (VARIANT_TRUE);  
 
      // set the source file 
      bstr = SysAllocString(L"c:\\source.avi"); 
      g_pPlay->put_SourceFile(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 
         g_pPlay->get_State (&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 
         g_pPlay->CheckSeekingCapabilities (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 
         g_pPlay->get_Rate (&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 
         g_pPlay->get_VideoWindowSizeMode(&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 
         g_pPlay->get_Volume (&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 
         g_pPlay->get_Balance (&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 
         g_pPlay->get_Mute(&f);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_MUTE, f ? MF_CHECKED : MF_UNCHECKED);  
    
         // check auto rewind 
         g_pPlay->get_AutoRewind (&f);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_AUTOREWIND, f ? MF_CHECKED : MF_UNCHECKED);  
    
         // check loop 
         g_pPlay->get_PlayCount (&l);  
         CheckMenuItem((HMENU) wParam, ID_CONTROL_LOOP, (l == 0) ? MF_CHECKED : MF_UNCHECKED);  
       
         // enable processors 
         g_pPlay->HasDialog (ltmmPlay_Dlg_VideoProcessors, &f);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PROCESSORS_VIDEO, f ? MF_ENABLED : MF_GRAYED);  
         g_pPlay->HasDialog (ltmmPlay_Dlg_AudioProcessors, &f);  
         EnableMenuItem((HMENU) wParam, ID_CONTROL_PROCESSORS_AUDIO, f ? MF_ENABLED : MF_GRAYED);  
 
         // check source 
         g_pPlay->get_SourceType (&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);  
 
         g_pPlay->get_AutoStart (&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 = g_pPlay->get_CurrentTrackingPosition (&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 = g_pPlay->get_TrackingSelectionStart(&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= g_pPlay->get_TrackingSelectionEnd(&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 = g_pPlay->get_CurrentFramePosition (&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 = g_pPlay->get_FrameDuration (&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 = g_pPlay->get_CurrentPosition (&d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Position: %f"), d);  
            }    
 
            // display the total duration 
            hr = g_pPlay->get_Duration(&d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Duration: %f"), d);  
            } 
 
            // display current selection start 
            hr = g_pPlay->get_SelectionStart (&d);  
            if(SUCCEEDED(hr))  
            { 
               if(p != sz)  
                  p += _stprintf(p, _T(", ")); 
               p += _stprintf(p, _T("Start: %f"), d);  
            } 
 
            // display current selection end 
            hr = g_pPlay->get_SelectionEnd (&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 
 
            // g_pPlay->EditGraph(); 
 
            g_pPlay->get_SourceType (&l);  
            if(l == ltmmPlay_Source_Array)  
            { 
               _stprintf(sz, _T("Stopped - [array]"));  
            } 
            else if(l == ltmmPlay_Source_HGlobal)  
            { 
               _stprintf(sz, _T("Stopped - [hglobal]"));  
            } 
            else 
            { 
               g_pPlay->get_SourceFile (&bstr);  
               _stprintf(sz, _T("Stopped - [%ls]"), bstr);  
               SysFreeString(bstr);  
            } 
            SetWindowText(hwnd, sz);  
            break;  
         case ltmmPlay_State_Paused:  
            g_pPlay->get_SourceType (&l);  
            if(l == ltmmPlay_Source_Array)  
            { 
               _stprintf(sz, _T("Paused - [array]"));  
            } 
            else if(l == ltmmPlay_Source_HGlobal)  
            { 
               _stprintf(sz, _T("Paused - [hglobal]"));  
            } 
            else 
            { 
               g_pPlay->get_SourceFile (&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 
          g_pPlay->get_FullScreenMode(&f); 
          if(f) 
          { 
             g_pPlay->put_FullScreenMode(VARIANT_FALSE); 
             return 0; 
          } 
       }      break; 
    case WM_DESTROY: 
       FreeSource(); 
       // no more notifications 
       g_pPlay->SetNotifyWindow((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 
          g_pPlay->get_AutoStart(&f); 
          g_pPlay->put_AutoStart(f ? VARIANT_FALSE : VARIANT_TRUE); 
          return 0; 
          break; 
       case ID_CONTROL_PLAY: 
          // play file 
          g_pPlay->Run(); 
          return 0; 
          break; 
       case ID_CONTROL_PAUSE: 
          // pause playback 
          g_pPlay->Pause(); 
          return 0; 
          break; 
       case ID_CONTROL_STOP: 
          // stop playback 
          g_pPlay->Stop(); 
          return 0; 
          break; 
       case ID_CONTROL_HALFSPEED: 
          // set to half the normal playback speed 
          g_pPlay->put_Rate(0.5); 
          return 0; 
          break; 
       case ID_CONTROL_NORMALSPEED: 
          // set to normal speed 
          g_pPlay->put_Rate(1.0); 
          return 0; 
          break; 
       case ID_CONTROL_SEEKSTART: 
          // seek to file start 
          g_pPlay->SeekStart(); 
          return 0; 
          break; 
       case ID_CONTROL_SEEKEND: 
          // seek to file end 
          g_pPlay->SeekEnd(); 
          return 0; 
          break; 
       case ID_CONTROL_SEEKSELECTIONSTART: 
          // seek to the start of the current selection 
          g_pPlay->SeekSelectionStart(); 
          return 0; 
          break; 
       case ID_CONTROL_SEEKSELECTIONEND: 
          // seek to the end of the current selection 
          g_pPlay->SeekSelectionEnd(); 
          return 0; 
          break; 
       case ID_CONTROL_SETSELECTIONSTART: 
          // set the start of the selection to the current position 
          g_pPlay->MarkSelectionStart(); 
          return 0; 
          break; 
       case ID_CONTROL_SETSELECTIONEND: 
          // set the end of the selection to the current position 
          g_pPlay->MarkSelectionEnd(); 
          return 0; 
          break; 
       case ID_CONTROL_CLEARSELECTION: 
          // clear the current selection 
          g_pPlay->get_Duration(&d); 
          g_pPlay->put_SelectionStart(0.0); 
          g_pPlay->put_SelectionEnd(d); 
          return 0; 
          break; 
       case ID_CONTROL_NEXTFRAME: 
          // goto the next frame 
          g_pPlay->NextFrame(); 
          return 0; 
          break; 
       case ID_CONTROL_PREVIOUSFRAME: 
          // goto the previous frame 
          g_pPlay->PreviousFrame(); 
          return 0; 
          break; 
       case ID_CONTROL_FIRSTFRAME: 
          // go to the first frame 
          g_pPlay->put_CurrentFramePosition(0); 
          return 0; 
          break; 
       case ID_CONTROL_LASTFRAME: 
          // go to the last frame 
          g_pPlay->get_FrameDuration(&l); 
          g_pPlay->put_CurrentFramePosition(l - 1); 
          return 0; 
          break; 
       case ID_CONTROL_STEPFORWARD1SEC: 
          // step forward 1 second 
          g_pPlay->get_CurrentPosition(&d); 
          g_pPlay->put_CurrentPosition(d + 1.0); 
          return 0; 
          break; 
       case ID_CONTROL_STEPFORWARD10: 
          // step forward 10% 
          g_pPlay->get_CurrentTrackingPosition(&l); 
          g_pPlay->put_CurrentTrackingPosition(l + 1000); 
          return 0; 
          break; 
       case ID_CONTROL_FITTOWINDOW: 
          // fit the video to the window 
          g_pPlay->put_VideoWindowSizeMode(ltmmFit); 
          return 0; 
          break; 
       case ID_CONTROL_STRETCHTOWINDOW: 
          // stretch the video to the window 
          g_pPlay->put_VideoWindowSizeMode(ltmmStretch); 
          return 0; 
          break; 
       case ID_CONTROL_MUTE: 
          // toggle mute 
          g_pPlay->get_Mute(&f); 
          g_pPlay->put_Mute(f ? VARIANT_FALSE : VARIANT_TRUE); 
          return 0; 
          break; 
       case ID_CONTROL_INCREASEVOLUME: 
          // increase the volume 
          g_pPlay->get_Volume(&l); 
          g_pPlay->put_Volume(min(0, l + 300)); 
          return 0; 
          break; 
       case ID_CONTROL_DECREASEVOLUME: 
          // decrease the volume 
          g_pPlay->get_Volume(&l); 
          g_pPlay->put_Volume(max(-10000, l - 300)); 
          return 0; 
          break; 
       case ID_CONTROL_PANRIGHT: 
          // pan balance to the right 
          g_pPlay->get_Balance(&l); 
          g_pPlay->put_Balance(min(10000, l + 300)); 
          return 0; 
          break; 
       case ID_CONTROL_PANLEFT: 
          // pan balance to the left 
          g_pPlay->get_Balance(&l); 
          g_pPlay->put_Balance(max(-10000, l - 300)); 
          return 0; 
          break; 
       case ID_CONTROL_LOOP: 
          // toggle looping 
          g_pPlay->get_PlayCount(&l); 
          g_pPlay->put_PlayCount(l ? 0 : 1); 
          return 0; 
          break; 
       case ID_CONTROL_FULLSCREEN: 
          // toggle fullscreen mode 
          g_pPlay->ToggleFullScreenMode(); 
          return 0; 
          break; 
       case ID_CONTROL_AUTOREWIND: 
          // toggle auto rewind 
          g_pPlay->get_AutoRewind(&f); 
          g_pPlay->put_AutoRewind(f ? VARIANT_FALSE : VARIANT_TRUE); 
          return 0; 
          break; 
       case ID_CONTROL_PROCESSORS_VIDEO: 
          // invoke video processor dialog box 
          g_pPlay->ShowDialog(ltmmPlay_Dlg_VideoProcessors, (long) hwnd); 
          return 0; 
          break; 
       case ID_CONTROL_PROCESSORS_AUDIO: 
          // invoke audio processor dialog box 
          g_pPlay->ShowDialog(ltmmPlay_Dlg_AudioProcessors, (long) hwnd); 
          return 0; 
          break; 
       case ID_CONTROL_SOURCE_FILE: 
          // set the source file 
          FreeSource(); 
          bstr = SysAllocString(MAKE_MEDIA_PATH("source.avi")); 
          g_pPlay->put_SourceFile(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; 
          g_pPlay->get_Title(&bstr); 
          p += _stprintf(p, _T("Title = '%ls'"), bstr ? bstr : L""); 
          SysFreeString(bstr); 
          g_pPlay->get_Author(&bstr); 
          p += _stprintf(p, _T(", Author = '%ls'"), bstr ? bstr : L""); 
          SysFreeString(bstr); 
          g_pPlay->get_Copyright(&bstr); 
          p += _stprintf(p, _T(", Copyright = '%ls'"), bstr ? bstr : L""); 
          SysFreeString(bstr); 
          g_pPlay->get_Description(&bstr); 
          p += _stprintf(p, _T(", Description = '%ls'"), bstr ? bstr : L""); 
          SysFreeString(bstr); 
          g_pPlay->get_Rating(&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 
       g_pPlay->get_VideoWindowLeft(&x); 
       g_pPlay->get_VideoWindowTop(&y); 
       g_pPlay->get_VideoWindowWidth(&cx); 
       g_pPlay->get_VideoWindowHeight(&cy); 
       SetRect(&rc, x, y, x + cx, y + cy); 
       pt.x = (short) LOWORD(lParam); 
       pt.y = (short) HIWORD(lParam); 
       if(PtInRect(&rc, pt)) 
       { 
          g_pPlay->get_State(&l); 
          if(l == ltmmPlay_State_Stopped || l == ltmmPlay_State_Paused) 
             g_pPlay->Run(); 
          else if(l == ltmmPlay_State_Running) 
             g_pPlay->Pause(); 
       }      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; 
   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 = (LPCWSTR)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) 
      g_pPlay->Release(); 
   CoUninitialize(); 
   return 0; 
}