The following code demonstrates how to copy a media sample's attributes and data to another media sample.
// 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 error if NULL if(!pSource || !pDest) return E_POINTER; // get the source actual data length hr = IltmmMediaSampleDisp_get_ActualDataLength (pSource, &cbData); if(FAILED(hr)) return hr; // now the dest 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 dest data length to 0 IltmmMediaSampleDisp_put_ActualDataLength (pDest, 0); } // copy the 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 dest time IltmmMediaSampleDisp_ResetTime (pDest); } else { // yes, copy to the dest 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 dest media time IltmmMediaSampleDisp_ResetMediaTime (pDest); } else { // yes, copy to the dest IltmmMediaSampleDisp_SetMediaTime (pDest, starttime.HighPart, starttime.LowPart, stoptime.HighPart, stoptime.LowPart); } return S_OK; }