多媒体网络通信技术大作业电信1203朱银啸01212093103091、题目：基于局域网的可视对讲系统设计2、系统开发环境与工具：（1）、硬件环境：实验室局域网（2）、软件环境：WindowsXP操作系统（3）、开发工具：自己熟悉的面向对象的网络通信编程工具与平台，相关音频、视频编码与传输协议类库3、要求与评分标准：（1）要求：在以上硬软件环境下，利用合适的开发工具，设计一套可视对讲软件，实现局域网内两台计算机之间的可视对讲功能，要求音视频信号连续性、实时性较好，满足正常交流需要。
（2）评分标准代码客户端请求连接线程（呼叫处理）关键代码如下：DWORD WINAPI ConnectThreadFunc(LPVOID pParam){CChatRoomDlg *pChatRoom = (CChatRoomDlg *)pParam; ASSERT(pChatRoom ! = NULL);pChatRoom ->m_ConnectSock = socket (AF_INET ,SOCK_STREAM , IPPROTO_TCP);if ( pChatRoom->m_ConnectSock == INVALID_SOCKET) { AfxMessageBox(_T("新建Socket 失败！"));return FALSE;}CString strServIp;pChatRoom->GetDlgItemText(IDC_IP_ADDR, strServIp);int iPort = pChatRoom ->GetDlgItemInt (IDC_CONNECT_PORT);if( iPort <= 0 || iPort > 65535 ) {AfxMessageBox(_T("请输入合适的端口：1 - 65535"));goto __Error_End;}char szIpAddr[16] = {0};USES_CONVERSION;strcpy_s(szIpAddr, 16, T2A(strServIp));sockaddr_in server;server.sin_family = AF_INET;server.sin_port = htons(iPort);server.sin_addr.s_addr = inet_addr(szIpAddr);if(connect(pChatRoom->m_ConnectSock,(struct sockaddr*)&server, sizeof(struct sockaddr)) == SOCKET_ERROR ){AfxMessageBox(_T("连接失败，请重试！"));goto __Error_End;}pChatRoom->ShowMsg(_T(" 系统信息：连接服务器成功！"));while( TRUE ) {if ( SOCKET_Select(pChatRoom->m_ConnectSock) ) {TCHAR szBuf[MAX_BUF_SIZE] = {0};int iRet = recv (pChatRoom->m_ConnectSock, (char*)szBuf, MAX_BUF_SIZE, 0);if ( iRet > 0 ) {pChatRoom->ShowMsg(szBuf);}else{pChatRoom->ShowMsg(_T("聊天服务器已停止，请重新进行连接！")); break;}}Sleep(500);}__Error_End:closesocket(pChatRoom->m_ConnectSock);return TRUE;}//捕获窗口BOOL VideoCapture::Initialize(){char devname[128]={0},devversion[128]={0};int index=0;BOOL ret = TRUE, ret1 = TRUE, ret2 = TRUE, ret3 = TRUE;TRACE("VideoCapture::Initialize\n");//创建一个AVICap捕获窗口m_capwnd = capCreateCaptureWindow("Capture",WS_POPUP,0,0,1,1,0,0); if(!m_capwnd){return FALSE;}//connect callback functionsret = capSetUserData(m_capwnd,this);//Change destroy functions also........ret1 = capSetCallbackOnVideoStream(m_capwnd,OnCaptureVideo);//得到已安装的捕获设备的名称及版本ret2 = capGetDriverDescription(index,devname,100,devversion,100);// Connect to webcam driver//使一个捕获窗口与一个捕获设备连接或关联ret3 = capDriverConnect(m_capwnd,index);if(!(ret && ret1 && ret2 && ret3)){// Device may be open already or it may not have been// closed properly last time.AfxMessageBox("Unable to open Video Capture Device");// log.WriteString("\n Unable to connect driver to the window");m_capwnd=NULL;return FALSE;}// Set the capture parametersif(SetCapturePara()==FALSE){// log.WriteString("\n Setting capture parameters failed"); capDriverDisconnect(m_capwnd); //使捕获窗口与一个捕获设备断开return FALSE;}return TRUE;}下面程序为设置CAPTUREPARAMS结构的实现代码：BOOL VideoCapture::SetCapturePara(){CAPTUREPARMS CapParms={0};capCaptureGetSetup(m_capwnd,&CapParms,sizeof(CapParms));//得到当前的捕获速度CapParms.fAbortLeftMouse = FALSE;CapParms.fAbortRightMouse = FALSE;CapParms.fYield = TRUE;CapParms.fCaptureAudio = FALSE;CapParms.wPercentDropForError = 80;if(!capCaptureSetSetup(m_capwnd,&CapParms,sizeof(CapParms))){// log.WriteString("\n Failed to set the capture parameters "); return FALSE;}// Set Video FormatcapGetVideoFormat(m_capwnd,&m_bmpinfo,sizeof(m_bmpinfo));m_bmpinfo.bmiHeader.biWidth=IMAGE_WIDTH;m_bmpinfo.bmiHeader.biHeight=IMAGE_HEIGHT;BOOL ret=capSetVideoFormat(m_capwnd,&m_bmpinfo,sizeof(m_bmpinfo)); // log.WriteString("\n Video parameters set properly");return ret;}//终止一个捕获任务BOOL VideoCapture::StopCapture(){capCaptureStop(m_capwnd);capCaptureAbort(m_capwnd);Sleep(500);return TRUE;}音视频编码处理就是对音视频进行压缩。
