Convert DVD with Subtitles for C

// This function will select one chapter in a specified title 
void SelectChapter(IltmmDVDTitle *pTitle, int nChapterIndex) 
{ 
   long nCount, i; 
   IltmmDVDTitle_get_ChapterCount(pTitle, &nCount); 
   for(i = 0; i < nCount; i++) 
   { 
      IltmmDVDChapter *pChapter; 
      if(IltmmDVDTitle_GetChapter(pTitle, i, &pChapter) == S_OK) 
      { 
         IltmmDVDChapter_put_Selected(pChapter, i == nChapterIndex ? VARIANT_TRUE : VARIANT_FALSE); 
         IltmmDVDChapter_Release(pChapter); 
      } 
   } 
} 
/* 
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 
   IltmmConvert_GetSubObject(pConvert, ltmmConvert_Object_SourceFilter, &punk); 
   if (punk) 
   { 
      IUnknown_QueryInterface(punk, &IID_IltmmDVDSource, (void**)&pDVDSource); 
      if (pDVDSource) 
      { 
         IltmmDVDTitle *pTitle; 
         long lCount, i; 
         long lVal; 
         // Select the main title 
         IltmmDVDSource_put_Selected(pDVDSource, 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. 
         IltmmDVDSource_get_TitleCount(pDVDSource, &lCount); 
         for (i = 0; i < lCount; i++) 
         { 
            // Get the title interface 
            IltmmDVDSource_GetTitle(pDVDSource, i, &pTitle); 
            if (pTitle) 
            { 
               long bSelected; 
               IltmmDVDTitle_get_Selected(pTitle, &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 
                  IltmmDVDTitle_get_SubpictureStreamCount(pTitle, &lVal); 
                  if(lVal > 0) 
                     // Select the first subpicture stream 
                  IltmmDVDTitle_put_SelectedSubpictureStream(pTitle, 0); 
               } 
               IltmmDVDTitle_Release(pTitle); 
            } 
         } 
         IltmmDVDSource_Release(pDVDSource); 
      } 
      IUnknown_Release(punk); 
   } 
} 
#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); 
   IltmmCompressors_Find(pCompressors, bstrCompressorName, &index); 
   IltmmCompressors_put_Selection(pCompressors, index); 
   SysFreeString(bstrCompressorName); 
} 
// convert one chapter with subtitles (close captioning) 
HRESULT ConvertOneChapterWithSubtitles() 
{ 
   IltmmConvert *pConvert; 
   IltmmCompressors *pCompressors; 
   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 
   IltmmConvert_put_UseDVDSource(pConvert, VARIANT_TRUE); 
   // set the source, compressors and target format 
   IltmmConvert_put_SourceFile(pConvert, L"e:\\video_ts\\video_ts.ifo"); 
   IltmmConvert_put_TargetFormat(pConvert, ltmmConvert_TargetFormat_MPEG2_PROGRAM); 
   // select the mpeg2 encoder 
   IltmmConvert_get_VideoCompressors(pConvert, &pCompressors); 
   SelectCompressor(pCompressors, LEAD_MPEG2_ENCODER); 
   IltmmCompressors_Release(pCompressors); 
   // select the mpeg audio encoder 
   IltmmConvert_get_AudioCompressors(pConvert, &pCompressors); 
   SelectCompressor(pCompressors, LEAD_MPEG_AUDIO_ENCODER); 
   IltmmCompressors_Release(pCompressors); 
   IltmmConvert_put_TargetFile(pConvert, L"c:\\i\\1.mpg"); 
   // this function is the interesting part of the example 
   SelectOneChapterAndSubtitles(pConvert); 
   hr = IltmmConvert_StartConvert(pConvert); 
   // wait for conversion to finish... Not very elegant, but we want to keep the example simple 
   MessageBox(NULL, TEXT("Wait to finish"), TEXT("wait"), MB_OK); 
   IltmmConvert_Release(pConvert); 
   return hr; 
}