Convert DVD with Subtitles for C++

// include the LEAD Multimedia TOOLKIT header 
#include "ltmm.h" 
 
// This function will select one chapter in a certain title 
void SelectChapter(IltmmDVDTitle *pTitle, int nChapterIndex) 
{ 
   long nCount; 
   pTitle->get_ChapterCount(&nCount); 
   for(int i = 0; i < nCount; i++) 
   { 
      IltmmDVDChapter *pChapter; 
      if(pTitle->GetChapter(i, &pChapter) == S_OK) 
      { 
         pChapter->put_Selected(i == nChapterIndex ? VARIANT_TRUE : VARIANT_FALSE); 
         pChapter->Release(); 
      } 
   } 
} 
 
   //This function will select the main title for conversion. 
   //Within the main title, it will select only the second chapter. 
   //It will also select the first subtitle stream. 
 
void SelectOneChapterAndSubtitles(IltmmConvert *pConvert) 
{ 
   IUnknown *punk; 
   IltmmDVDSource* pDVDSource; 
   // Get the DVD source interface 
   pConvert->GetSubObject(ltmmConvert_Object_SourceFilter, &punk); 
   if (punk) 
   { 
      punk->QueryInterface(IID_IltmmDVDSource, (void**)&pDVDSource); 
      if (pDVDSource) 
      { 
         IltmmDVDTitle *pTitle; 
         long lCount; 
         long lVal; 
 
         // Select the main title 
         pDVDSource->put_Selected(ltmmDVDSource_Main_Selected); 
         // We now need to select one chapter and enable subtitles for this title 
         // For that, we will loop through the titles and find out which one was selected above 
         // Get the title count in the disc 
         pDVDSource->get_TitleCount(&lCount); 
         for (int i = 0; i < lCount; i++) 
         { 
            // Get the title interface 
            pDVDSource->GetTitle(i, &pTitle); 
            if (pTitle) 
            { 
               long bSelected; 
               pTitle->get_Selected(&bSelected); 
               if(bSelected) 
               { 
                  // we found the main title 
                  // (Optional step). We will convert only one chapter to speed up the conversion.  
                  // We will select the 2nd chapte, because the first chapter will sometimes have movie credits and little dialogue 
                  // Chapters are 0-based, so the second chapter has index 1 
                  SelectChapter(pTitle, 1); 
                  // Get the subpicture stream count 
                  pTitle->get_SubpictureStreamCount(&lVal); 
                  if(lVal > 0) 
                     // Select the first subpicture stream 
                     pTitle->put_SelectedSubpictureStream(0); 
               } 
               pTitle->Release(); 
            } 
         } 
         pDVDSource->Release(); 
      } 
      punk->Release(); 
   } 
} 
 
#define LEAD_MPEG2_ENCODER L"@device:sw:{33D9A760-90C8-11D0-BD43-00A0C911CE86}\\LEAD MPEG2 Encoder (3.0)" 
#define LEAD_MPEG_AUDIO_ENCODER L"@device:sw:{33D9A761-90C8-11D0-BD43-00A0C911CE86}\\LEAD MPEG Audio Encoder (2.0)" 
 
// select a certain encoder 
void SelectCompressor(IltmmCompressors *pCompressors, LPCWSTR pszCompressorName) 
{ 
   long index; 
   BSTR bstrCompressorName = SysAllocString(pszCompressorName); 
   pCompressors->Find(bstrCompressorName, &index); 
   pCompressors->put_Selection(index); 
   SysFreeString(bstrCompressorName); 
} 
 
// helper function to wait for conversion to complete 
void WaitForCompletion(IltmmConvert *pConvert) 
{ 
   long lState = ltmmConvert_State_Running; 
   MSG msg; 
 
   pConvert->get_State(&lState); 
 
   while(lState != ltmmConvert_State_Stopped) 
   {  
      if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) 
      { 
         TranslateMessage(&msg); 
         DispatchMessage(&msg); 
      } 
       
      pConvert->get_State(&lState); 
   } 
} 
 
// convert one chapter with subtitles (close captioning) 
HRESULT ConvertOneChapterWithSubtitles() 
{ 
   IltmmConvert *pConvert; 
   HRESULT hr = CoCreateInstance(CLSID_ltmmConvert, NULL, CLSCTX_INPROC_SERVER, IID_IltmmConvert, (void**) &pConvert); 
   if(FAILED(hr)) 
      return hr; 
 
   // use the DVD source for greater control over the DVD conversion process 
   pConvert->put_UseDVDSource(VARIANT_TRUE); 
 
   // set the source, compressors and target format 
   BSTR bstr = ::SysAllocString(MAKE_MEDIA_PATH("video_ts.ifo")); 
   pConvert->put_SourceFile(bstr); 
   SysFreeString(bstr); 
 
   pConvert->put_TargetFormat(ltmmConvert_TargetFormat_MPEG2_PROGRAM); 
   IltmmCompressors *pCompressors; 
 
   // select mpeg2 encoder 
   pConvert->get_VideoCompressors(&pCompressors); 
   SelectCompressor(pCompressors, LEAD_MPEG2_ENCODER); 
   pCompressors->Release(); 
 
   // select mpeg audio encoder 
   pConvert->get_AudioCompressors(&pCompressors); 
   SelectCompressor(pCompressors, LEAD_MPEG_AUDIO_ENCODER); 
   pCompressors->Release(); 
   bstr = ::SysAllocString(MAKE_MEDIA_PATH("1.mpg")); 
   pConvert->put_TargetFile(bstr); 
   SysFreeString(bstr); 
 
   // this function is the interesting part of the example 
   SelectOneChapterAndSubtitles(pConvert); 
   hr = pConvert->StartConvert(); 
 
   // wait for conversion to finish 
   WaitForCompletion(pConvert); 
 
   pConvert->Release(); 
   return hr; 
}