compression.cpp

本系统可以在局域网内实现C/S形式的语音聊天。原理简单易懂

		HACMSTREAM hstr = NULL;
		mmr = acmStreamOpen(&hstr,
						NULL, // any driver
						&m_wfSrc, // source format
						pwfPCM, // destination format
						NULL, // no filter
						NULL, // no callback
						0, // instance data (not used)
						ACM_STREAMOPENF_NONREALTIME); // flags
		if (mmr) {
			AfxMessageBox("Failed to open a stream to do PCM to PCM conversion\n");
			return 0;
		}
		// fill in the conversion info
		ACMSTREAMHEADER strhdr;
		memset(&strhdr, 0, sizeof(strhdr));
		strhdr.cbStruct = sizeof(strhdr);
		strhdr.pbSrc = m_pSrcData; // the source data to convert
		strhdr.cbSrcLength = m_dwSrcBytes;
		strhdr.pbDst = pDst1Data;
		strhdr.cbDstLength = dwDst1Bytes;

		// prep the header
		mmr = acmStreamPrepareHeader(hstr, &strhdr, 0); 
	
		// convert the data
		TRACE("Converting to intermediate PCM format...\n");
		mmr = acmStreamConvert(hstr, &strhdr, 0);
		if (mmr) {
			AfxMessageBox("Failed to do PCM to PCM conversion\n");
			return 0;
		}
		TRACE("Converted OK\n");
	
		// close the stream
		acmStreamClose(hstr, 0);

		///////////////////////////////////////////////////////////////////////////////////
		// convert the intermediate PCM format to the final format
		// open the driver
		HACMDRIVER had = NULL;
		mmr = acmDriverOpen(&had, hadid, 0);
		if (mmr) {
			AfxMessageBox("Failed to open driver\n");
			return 0;
		}

		// open the conversion stream
		// Note the use of the ACM_STREAMOPENF_NONREALTIME flag. Without this
		// some software compressors will report error 512 - not possible
		mmr = acmStreamOpen(&hstr,
						had, // driver handle
						pwfPCM, // source format
						pwfDrv, // destination format
						NULL, // no filter
						NULL, // no callback
						0, // instance data (not used)
						ACM_STREAMOPENF_NONREALTIME ); // flags
		if (mmr) {
			AfxMessageBox("Failed to open a stream to do PCM to driver format conversion\n");
			return 0;
		}

		// fill in the conversion info
		ACMSTREAMHEADER strhdr2;
		memset(&strhdr2, 0, sizeof(strhdr2));
		strhdr2.cbStruct = sizeof(strhdr2);
		strhdr2.pbSrc = pDst1Data; // the source data to convert
		strhdr2.cbSrcLength = dwDst1Bytes;
		strhdr2.pbDst = pDst2Data;
		strhdr2.cbDstLength = dwDst2Bytes;

		// prep the header
		mmr = acmStreamPrepareHeader(hstr, &strhdr2, 0); 

		// convert the data
		TRACE("Converting to final format...\n");
		mmr = acmStreamConvert(hstr, &strhdr2, 0);
		if (mmr) {
			AfxMessageBox("Failed to do PCM to driver format conversion\n");
			return 0;
		}
		TRACE("Converted OK\n");

		// close the stream and driver
		mmr = acmStreamClose(hstr, 0);
		mmr = acmDriverClose(had, 0);

		// show the conversion stats
		TRACE("Source wave had %lu bytes\n", m_dwSrcBytes);
		TRACE("Converted wave has %lu bytes\n", strhdr2.cbDstLengthUsed);
		TRACE("Compression ratio is %f\n", (double)m_dwSrcBytes / (double) strhdr2.cbDstLengthUsed); 
		length=strhdr2.cbDstLengthUsed;
		
		return length;
	}
	else{
		if(detLength<length){
			AfxMessageBox("Error using the function!");
			return 0;
		}
		memcpy(pDetData,pDst2Data,length);
		return length;
	}
}


BOOL CCompression::ConvertSend(SOCKET s, SOCKADDR_IN addr)
{
	MyConvert(TRUE,NULL,0);
	int iError=sendto(s,(char *)pDst2Data,length,0,(LPSOCKADDR)&addr,sizeof(addr));
	if(iError==SOCKET_ERROR)
		return FALSE;
	return TRUE;
}

void CCompression::SetDstSamples(long bytes, unsigned char *pDstData)
{
	dwDst2Bytes=bytes;
	pDst2Data=(BYTE*)malloc(dwDst2Bytes);
	memcpy(pDst2Data,pDstData,dwDst2Bytes);
}

BOOL CCompression::PrepareSpace(BOOL bCompression)
{
	if(bCompression){
		dwDst1Samples = m_dwSrcSamples * pwfPCM->nSamplesPerSec / m_wfSrc.nSamplesPerSec;
		dwDst1Bytes = dwDst1Samples * pwfPCM->wBitsPerSample / 8;
 		pDst1Data =(BYTE*)malloc(dwDst1Bytes);
	
#ifdef _DEBUG
		memset(pDst1Data, 0, dwDst1Bytes);
#endif
		dwDst2Bytes = pwfDrv->nAvgBytesPerSec * dwDst1Samples / pwfPCM->nSamplesPerSec;
		dwDst2Bytes = dwDst2Bytes * 3 / 2; // add a little room
		pDst2Data =(BYTE*)malloc(dwDst2Bytes);
#ifdef _DEBUG
		memset(pDst2Data, 0, dwDst2Bytes);
#endif
	}
	else{
		dwDst1Samples=pwfPCM->nSamplesPerSec*dwDst2Bytes/pwfDrv->nAvgBytesPerSec;
		dwDst1Bytes = dwDst1Samples* 3 / 2; // add a little room
		pDst1Data = (BYTE*)malloc(dwDst1Bytes);
#ifdef _DEBUG
		memset(pDst1Data, 0, dwDst1Bytes);
#endif
		m_dwSrcSamples=dwDst1Samples*m_wfSrc.nSamplesPerSec/pwfPCM->nSamplesPerSec;
		m_dwSrcBytes=m_dwSrcSamples*m_wfSrc.wBitsPerSample / 8;
		m_pSrcData = (BYTE*)malloc(m_dwSrcBytes);
	
#ifdef _DEBUG
		memset(m_pSrcData, 0, m_dwSrcBytes);
#endif
	}
	return TRUE;
}

long CCompression::UnConvert(BOOL bQuery, unsigned char *pSrcData, long bytes)
{
	if(bQuery){
		MMRESULT mmr;
		HACMSTREAM hstr = NULL;

		HACMDRIVER had = NULL;
		mmr = acmDriverOpen(&had, hadid, 0);
		if (mmr) {
			AfxMessageBox("Failed to open driver\n");
			return 0;
		}
		// open the conversion stream
		// Note the use of the ACM_STREAMOPENF_NONREALTIME flag. Without this
		// some software compressors will report error 512 - not possible
		mmr = acmStreamOpen(&hstr,
						had, // driver handle
						pwfDrv, // source format
						pwfPCM, // destination format
						NULL, // no filter
						NULL, // no callback
						0, // instance data (not used)
						ACM_STREAMOPENF_NONREALTIME ); // flags
		if (mmr) {
			AfxMessageBox("Failed to open a stream to do PCM to driver format conversion\n");
			return 0;
		}
		// fill in the conversion info
		ACMSTREAMHEADER strhdr2;
		memset(&strhdr2, 0, sizeof(strhdr2));
		strhdr2.cbStruct = sizeof(strhdr2);
		strhdr2.pbSrc = pDst2Data; // the source data to convert
		strhdr2.cbSrcLength = dwDst2Bytes;
		strhdr2.pbDst = pDst1Data;
		strhdr2.cbDstLength = dwDst1Bytes;

		// prep the header
		mmr = acmStreamPrepareHeader(hstr, &strhdr2, 0); 

		// convert the data
		TRACE("Converting to final format...\n");
		mmr = acmStreamConvert(hstr, &strhdr2, 0);
		if (mmr) {
			AfxMessageBox("Failed to do PCM to driver format conversion\n");
			return 0;
		}
		TRACE("Converted OK\n");
		// close the stream and driver
		mmr = acmStreamClose(hstr, 0);
		mmr = acmDriverClose(had, 0);
		
		DWORD tmpBytes=strhdr2.cbDstLengthUsed;
		// show the conversion stats
		TRACE("Source wave had %lu bytes\n", m_dwSrcBytes);
		TRACE("Converted wave has %lu bytes\n", strhdr2.cbDstLengthUsed);
		TRACE("Compression ratio is %f\n", (double)m_dwSrcBytes / (double) strhdr2.cbDstLengthUsed); 

		mmr = acmStreamOpen(&hstr,
						NULL, // any driver
						pwfPCM, // source format
						&m_wfSrc, // destination format
						NULL, // no filter
						NULL, // no callback
						0, // instance data (not used)
						ACM_STREAMOPENF_NONREALTIME ); // flags
		if (mmr) {
			AfxMessageBox("Failed to open a stream to do PCM to PCM conversion\n");
			return 0;
		}
		// fill in the conversion info
		ACMSTREAMHEADER strhdr;
		memset(&strhdr, 0, sizeof(strhdr));
		strhdr.cbStruct = sizeof(strhdr);
		strhdr.pbSrc = pDst1Data; // the source data to convert
		strhdr.cbSrcLength = tmpBytes;
		strhdr.pbDst = m_pSrcData;
		strhdr.cbDstLength = m_dwSrcBytes;
		// prep the header
		mmr = acmStreamPrepareHeader(hstr, &strhdr, 0); 
		// convert the data
		TRACE("Converting to intermediate PCM format...\n");
		mmr = acmStreamConvert(hstr, &strhdr, 0);
		if (mmr) {
			AfxMessageBox("Failed to do PCM to PCM conversion\n");
			return 0;
		}
		TRACE("Converted OK\n");
		// close the stream
		acmStreamClose(hstr, 0);

		///////////////////////////////////////////////////////////////////////////////////
		// convert the intermediate PCM format to the final format
		// open the driver
		unlength=strhdr.cbDstLengthUsed;
		
		return unlength;
	}
	else{
		if(bytes<unlength){
			memcpy(pSrcData,m_pSrcData,bytes);	
			return 0;
		}
		memcpy(pSrcData,m_pSrcData,unlength);
		return unlength;
	}
}