Copying ltmmMediaSample Attributes and Data for C

// define helper macros for using interfaces under C 
#ifndef COBJMACROS 
   #define COBJMACROS 
#endif 
 
// include the LEAD Multimedia TOOLKIT header 
#include "ltmm.h"  
 
///////////////////////////////////////////////////////////////// 
// CopyMediaSampleAttributes 
// copies data and attributes from one sample to another 
// pDest - destination sample interface 
// pSource - source sample interface 
// 
HRESULT CopyMediaSampleAttributesExample (IltmmMediaSampleDisp* pDest, IltmmMediaSampleDisp* pSource) 
{ 
   HRESULT hr; 
   VARIANT_BOOL f; 
   LARGE_INTEGER starttime; 
   LARGE_INTEGER stoptime; 
   VARIANT var; 
   long cbData; 
   long cbBuffer; 
   IltmmMediaTypeDisp* pMediaType; 
 
   // return an error if NULL 
   if(!pSource || !pDest) 
      return E_POINTER; 
 
   // get the source's actual data length 
   hr = IltmmMediaSampleDisp_get_ActualDataLength (pSource, &cbData); 
   if(FAILED(hr)) 
      return hr; 
 
   // now the destination maximum buffer size 
   hr = IltmmMediaSampleDisp_get_BufferSize(pDest, &cbBuffer); 
   if(FAILED(hr)) 
      return hr; 
 
   // if no room for the data, return an error 
   if(cbData > cbBuffer) 
      return E_OUTOFMEMORY; 
 
   // any data to copy? 
   if(cbData) 
   { 
      // yes, then copy away 
      hr = IltmmMediaSampleDisp_GetData (pSource, cbData, &var); 
      if(FAILED(hr)) 
         return hr; 
      hr = IltmmMediaSampleDisp_SetData (pDest, cbData, var); 
      VariantClear(&var); 
      if(FAILED(hr)) 
         return hr; 
   } 
   else 
   { 
      // no, just set the destination data length to 0 
      IltmmMediaSampleDisp_put_ActualDataLength (pDest, 0); 
   } 
 
   // copy the media type, if there is one 
   pMediaType = NULL; 
   IltmmMediaSampleDisp_GetMediaType (pSource, &pMediaType); 
   if(pMediaType) 
   { 
      IltmmMediaSampleDisp_SetMediaType (pDest, pMediaType); 
      IUnknown_Release(pMediaType); 
   } 
 
   // copy discontinuity 
   f = VARIANT_FALSE; 
   IltmmMediaSampleDisp_get_Discontinuity(pSource, &f); 
   IltmmMediaSampleDisp_put_Discontinuity (pDest, f); 
 
   // copy preroll 
   f = VARIANT_FALSE; 
   IltmmMediaSampleDisp_get_Preroll(pSource, &f); 
   IltmmMediaSampleDisp_put_Preroll (pDest, f); 
 
   // copy syncpoint 
   f = VARIANT_FALSE; 
   IltmmMediaSampleDisp_get_SyncPoint(pSource, &f); 
   IltmmMediaSampleDisp_put_SyncPoint (pDest, f); 
 
   // is the time available? 
   hr = IltmmMediaSampleDisp_GetTime (pSource, &starttime.HighPart, (long*) &starttime.LowPart, &stoptime.HighPart, (long*) &stoptime.LowPart); 
   if(FAILED(hr)) 
   { 
      // no, then reset the destination time 
      IltmmMediaSampleDisp_ResetTime (pDest); 
   } 
   else 
   { 
      // yes, copy to the destination 
      IltmmMediaSampleDisp_SetTime (pDest, starttime.HighPart, starttime.LowPart, stoptime.HighPart, stoptime.LowPart); 
   } 
 
   // is the media time available? 
   hr = IltmmMediaSampleDisp_GetMediaTime (pSource, &starttime.HighPart, (long*) &starttime.LowPart, &stoptime.HighPart, (long*) &stoptime.LowPart); 
   if(FAILED(hr)) 
   { 
      // no, then reset the destination media time 
      IltmmMediaSampleDisp_ResetMediaTime (pDest); 
   } 
   else 
   { 
      // yes, copy to the destination 
      IltmmMediaSampleDisp_SetMediaTime (pDest, starttime.HighPart, starttime.LowPart, stoptime.HighPart, stoptime.LowPart); 
   } 
 
   return S_OK; 
}