多媒体网络通信技术大作业.doc

.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）评分标准系统原理分析（20分）1.系统原理概述（10分）2.关键技术分析（10分）系统总体方案设计（30分）1.按模块化设计要求画系统结构图（15分）2数据流分析（15分）系统具体设计（30分）呼叫处理模块流程图与关键代码（6分）音视频采集与播放模块流程图与关键代码（6分）音视频处理（编解码）模块流程图与关键代码（6分）音视频封包与解析模块流程图与关键代码（6分）音视频发送与接收模块流程图与关键代码（6分）系统测试与评价（20）实现语音通信（6分）实现视频通信（6分）实现音视频同步（8分）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 65535 ) AfxMessageBox(_T(请输入合适的端口：1 - 65535);goto _Error_End;char szIpAddr16 = 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 szBufMAX_BUF_SIZE = 0;int iRet = recv (pChatRoom-m_ConnectSock, (char*)szBuf, MAX_BUF_SIZE, 0);if ( iRet 0 ) pChatRoom-ShowMsg(szBuf);elsepChatRoom-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 devname128=0,devversion128=0; int index=0; BOOL ret = TRUE, ret1 = TRUE, ret2 = TRUE, ret3 = TRUE; TRACE(VideoCapture:Initializen); /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 Format capGetVideoFormat(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。MPEG-4编码算法的完整源代码如下：class CVideoEncoderX264 :public:CVideoEncoderX264(void);CVideoEncoderX264(void);virtual bool Connect(CVideoEnDecodeNotify* pNotify, const CVideoEnDecodeItem& Item);virtual void Release(void);virtual void Encode(BYTE* pInData, int nLen, BYTE* pOutBuf, int& nOutLen, int& nKeyFrame);private: x264_picture_t m_Pic;x264_t *h; x264_param_t param; void Flush(void);文件：VideoEncoderX264.cppbool CVideoEncoderX264:Connect(CVideoEnDecodeNotify* pNotify, const CVideoEnDecodeItem& Item)CBase:Connect(pNotify, Item);ParseSize(Item.m_stSize);x264_param_default( ¶m );param.i_threads = 1;param.i_frame_total = 0;param.i_width = m_nWidth;param.i_height = m_nHeight;param.i_keyint_min = Item.m_nKeyInterval;param.i_keyint_max = Item.m_nKeyInterval * 10;param.i_fps_num = Item.m_nFps;*/param.i_log_level = X264_LOG_NONE;if( ( h = x264_encoder_open( ¶m ) ) = NULL ) return false; /* Create a new pic */x264_picture_alloc( &m_Pic, X264_CSP_I420, param.i_width, param.i_height );return true;void CVideoEncoderX264:Release(void)Flush();x264_picture_clean( &m_Pic );x264_encoder_close( h );CBase:Release();void CVideoEncoderX264:Encode(BYTE* pInData, int nLen, BYTE* pOutBuf, int& nOutLen, int& nKeyFrame)if(nLen != param.i_width * param.i_height * 3)return;param.i_frame_total +;memcpy(m_Pic.img.plane0, pInData, param.i_width * param.i_height);memcpy(m_Pic.img.plane1, pInData + param.i_width * param.i_height, param.i_width * param.i_height / 4);memcpy(m_Pic.img.plane2, pInData + param.i_width * param.i_height * 5 / 4, param.i_width * param.i_height / 4);m_Pic.i_pts = (int64_t)param.i_frame_total * param.i_fps_den;static x264_picture_t pic_out;x264_nal_t *nal = NULL;int i_nal, i;if( &m_Pic )m_Pic.i_type = X264_TYPE_AUTO;m_Pic.i_qpplus1 = 0;/TraceTime(x264_encoder_encode begin);if( x264_encoder_encode( h, &nal, &i_nal, &m_Pic, &pic_out ) 0 ) return;/TraceTime(x264_encoder_encode end);int nOutCanUse = nOutLen;nOutLen = 0;for( i = 0; i 0 )nOutLen += i_size;nOutCanUse -= i_size;nKeyFrame = pic_out.i_type=X264_TYPE_IDR;/ | (pic_out.i_type=X264_TYPE_I & coCfg-x264_max_ref_frames=1)void CVideoEncoderX264:Flush(void)x264_picture_t pic_out;x264_nal_t *nal;int i_nal, i;int i_file = 0;if( x264_encoder_encode( h, &nal, &i_nal, NULL, &pic_out ) 0 )不妨假设创建的线程名为sendThread，发送代码如下：while(1)isOK=true; /准备就绪SuspendThread(sendThread); /挂起线程isOK=false; /线程正在发送数据int length=frameLength; /待发数据长度if(length0) n=send(sock,(char*)imageBuf+sendCount,length,0); /发送数据，/imageBuf是指针，指向待发数据帧if(n=SOCKET_ERROR) /网络出现异常，则退出线程break;length-=n;sendCount+=n;接收端创建一个线程专门用来执行数据接收。不妨假设线程名为recThread，核心代码实现如下：while(temp!=SOCKET_ERROR)if(!isStart) /帧数据是否开始，true表示开始if(endNum3) /endNum纪录当前接收未处理的数据endNum=0;temp=recv(clisock,(char*)(recBuf+endNum),1000,0);/从缓冲区读取数据startPos=serchStr(temp+endNum); /查找帧开始标志if(startPo