AVObjects Library: Samples

HRESULT CMuxedPCM::ReadFrame(ULONGLONG ullFrame, BYTE* pbFrame, DWORD cbFrame, DWORD* pcbActual, 
								  LONG* plTempOffset/* = NULL*/, bool bReverse/* = false*/,DWORD nSkip /*= 0*/, bool bDirectRead/* = false*/) 
{
	ATLASSERT(pbFrame != NULL);
	if(pbFrame == NULL) return E_INVALIDARG;
	ATLASSERT(pcbActual != NULL);
	if(pcbActual == NULL) return E_INVALIDARG;
 
	DWORD cbFrameSize = GetFrameSize();
	ATLASSERT(cbFrame >= cbFrameSize);
	if(cbFrame < cbFrameSize) return E_INVALIDARG;
 
	DWORD dwSourceCount = m_source.GetSize();
	ATLASSERT(dwSourceCount > 0);
 
	if (dwSourceCount == 1)
		return m_source[0]->ReadFrame(ullFrame, pbFrame, cbFrame, pcbActual, plTempOffset, bReverse, nSkip, bDirectRead);
 
	CMType mt;
	HRESULT hr = FillMT(mt);
	if (hr != S_OK)
		return hr;
 
	ATLASSERT(mt.IsAudio());
	const WAVEFORMATEX* pwf = mt;
 
 
	DWORD cbBuf = cbFrame / dwSourceCount;
	CMAlloc mem;
	if (!mem.Alloc(cbBuf))
		return hr;
 
	BYTE* pbBuf = mem.Memory();
	ATLASSERT(pbBuf);
 
	DWORD nBlockAlign = pwf->nBlockAlign / dwSourceCount;
	*pcbActual = 0;
 
//	ATLTRACE2(atlTraceGeneral, 2, _T("%s::ReadFrame(): ")
//		_T("MuxedReadStart: ullFrame = %I64u(0x%I64x), cbFrame = %d(0x%x)\n"), GetClassName(), ullFrame, ullFrame,
//		cbFrame, cbFrame);
 
	memset(pbFrame, 0, cbFrame);
	for(DWORD n = 0; n < dwSourceCount; n++)
	{
		DWORD cbActual = 0;
		hr = m_source[n]->ReadFrame(ullFrame, pbBuf, cbBuf, &cbActual, NULL, bReverse, nSkip, bDirectRead);
		if (hr != S_OK)
			return hr;
 
		if (cbActual > *pcbActual)
			*pcbActual = cbActual;
 
		BYTE* pbIn = pbBuf;
		BYTE* pbOut = pbFrame + nBlockAlign * n;
		BYTE* pbEnd = pbBuf + cbActual;
		for(; pbIn < pbEnd; pbIn += nBlockAlign, pbOut += pwf->nBlockAlign)
		{
			//DWORD cbLen = (pbIn + nBlockAlign >= pbEnd)? pbEnd - pbIn : nBlockAlign;
			memcpy(pbOut, pbIn, nBlockAlign);
		}
	}
 
	*pcbActual *= dwSourceCount;
//	ATLTRACE2(atlTraceGeneral, 2, _T("%s::ReadFrame(): ")
//		_T("MuxedReadAStop Actual: %d(0x%x)\n"), GetClassName(), *pcbActual, *pcbActual);
//	Debug_Dump(atlTraceGeneral, 2, *pcbActual, pbFrame);
 
	return S_OK;	
};