Simple Media Player for C++

The following code demonstrates a simple media player application. It utilizes most of the functions available in the ltmmPlay object.

#define MAKE_MEDIA_PATH(pFileName) (TEXT("C:\\LEADTOOLS 17.5\\Media\\")TEXT(pFileName))


#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 preferred renderer
      g_pPlay->put_PreferredVideoRenderer(ltmmVideoRenderer_VMR9); 

      // 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 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;
}