• GB/T 28181联网系统通信协议结构和技术实现

    技术回顾

    在本文开头，我们先一起回顾下GB/T28181联网系统通信协议结构：

    联网系统在进行视音频传输及控制时应建立两个传输通道：会话通道和媒体流通道。

    • 会话通道用于在设备之间建立会话并传输系统控制命令；
    • 媒体流通道用于传输视音频数据，经过压缩编码的视音频流采用流媒体协议 RTP/RTCP传输。

    具体如下图

    我们先来看看会话初始协议：

    • 安全注册、实时视音频点播、历史视音频的回放等应用的会话控制采用IETF RFC 3261规定的 Register、Invite等请求和响应方法实现；
    • 历史视音频回放控制采用SIP扩展协议IETF RFC 2976规定的INFO方法实现；
    • 前端设备控制、信息查询、报警事件通知和分发等应用的会话控制采用 SIP扩展协议IETF RFC 3428规定的Message方法实现；
    • SIP消息应支持基于UDP和 TCP的传输；
    • 互联的系统平台及设备不应向对方的SIP端口发送应用无关消息，避免应用无关消息占用系统平台及设备的SIP消息处理资源。

    接下来是会话描述协议

    联网系统有关设备之间会话建立过程的会话协商和媒体协商应采用IETF RFC 4566协议描述，主要内容包括会话描述、媒体信息描述、时间信息描述。

    会话协商和媒体协商信息应采用SIP消息的消息体携带传输。

    控制描述协议

    联网系统有关前端设备控制、报警信息、设备目录信息等控制命令应采用监控报警联网系统控制描述协议(MANSCDP)描述。

    联网系统控制命令应采用SIP消息Message的消息体携带传输。

    媒体回放控制协议

    历史视音频的回放控制命令应采用监控报警联网系统实时流协议(MANSRTSP),实现设备在端到端之间对视音频流的正常播放、快速、暂停、停止、随机拖动播放等远程控制。

    历史媒体的回放控制命令采用SIP消息Info的消息体携带传输。

    由于我们主要侧重于GB/T 28181音视频实时数据接入，这块未做实现，有相关需求的开发者，参考对应的spec章节即可。

    媒体传输和媒体编解码协议

    • 媒体流在联网系统IP网络上传输时应支持 RTP传输，媒体流发送源端应支持控制媒体流发送峰值功能；
    • RTP的负载应采用如下两种格式之一：基于 PS封装的视音频数据或视音频基本流数据；
    • 媒体流的传输应采用IETF RFC 3550规定的 RTP协议，提供实时数据传输中的时间戳信息及各数据流的同步；应采用IETFRFC3550规定的RTCP协议，为按序传输数据包提供可靠保证，提供流量控制和拥塞控制。

    技术实现

    下面以Android平台GB/T 28181设备接入实现为例，大概介绍下相关的参数配置和设计细节：

    先说参数配置，除了常规的链接sip server基础配置外，我们根据规范要求，添加了注册有效期、心跳间隔、心跳间隔失败次数、信令传输协议等配置：

    1. /*** GB28181 相关参数，可以修改相关参数后测试 ***/
    2.     GBSIPAgent     gb28181_agent_             = null;
    3.     private int    gb28181_sip_local_port_    = 12070;
    4.     private String gb28181_sip_server_id_     = "34020000002000000001";
    5.     private String gb28181_sip_domain_        = "3402000000";
    6.     private String gb28181_sip_server_addr_   = "192.168.0.105";
    7.     private int    gb28181_sip_server_port_   = 15060;
    8.  
    9.     private String gb28181_sip_user_agent_filed_  = "NT GB28181 User Agent V1.2";
    10.     private String gb28181_sip_username_   = "31011500991320000069";
    11.     private String gb28181_sip_password_   = "12345678";
    12.  
    13.     private int gb28181_reg_expired_           = 3600; // 注册有效期时间最小3600秒
    14.     private int gb28181_heartbeat_interval_    = 20; // 心跳间隔GB28181默认是60, 目前调整到20秒
    15.     private int gb28181_heartbeat_count_       = 3; // 心跳间隔3次失败，表示和服务器断开了
    16.     private int gb28181_sip_trans_protocol_    = 0; // 0表示信令用UDP传输, 1表示信令用TCP传输
    17.  
    18.     private long gb28181_rtp_sender_handle_ = 0;
    19.     private int  gb28181_rtp_payload_type_  = 96;
    20.  
    21.     private long player_handle_ = 0;
    22.     private long rtp_receiver_handle_ = 0;
    23.     private AtomicLong last_received_audio_data_time_ = new AtomicLong(0);
    24.  
    25.     /*** GB28181 相关参数，可以修改相关参数后测试 ***/

    为了测试方便，我们在界面加了个启动/停止GB28181的按钮：

    1. /*
    2.  * Github: https://github.com/daniulive/SmarterStreaming
    3.  */
    4. class ButtonGB28181AgentListener implements OnClickListener {
    5.   public void onClick(View v) {
    6.     stopAudioPlayer();
    7.     destoryRTPReceiver();
    8.  
    9.     gb_broadcast_source_id_ = null;
    10.     gb_broadcast_target_id_ = null;
    11.     btnGB28181AudioBroadcast.setText("GB28181语音广播");
    12.     btnGB28181AudioBroadcast.setEnabled(false);
    13.  
    14.     stopGB28181Stream();
    15.     destoryRTPSender();
    16.  
    17.     if (null == gb28181_agent_ ) {
    18.       if( !initGB28181Agent() )
    19.         return;
    20.     }
    21.  
    22.     if (gb28181_agent_.isRunning()) {
    23.       gb28181_agent_.terminateAllPlays(true);// 目前测试下来,发送BYE之后,有些服务器会立即发送INVITE,是否发送BYE根据实际情况看
    24.       gb28181_agent_.stop();
    25.       btnGB28181Agent.setText("启动GB28181");
    26.     }
    27.     else {
    28.       if ( gb28181_agent_.start() ) {
    29.         btnGB28181Agent.setText("停止GB28181");
    30.       }
    31.     }
    32.   }
    33. }

    其中，initGB2818Agent()主要是基础参数设置，对应的实现如下：

    1. private boolean initGB28181Agent() {
    2.   if ( gb28181_agent_ != null )
    3.     return  true;
    4.  
    5.   getLocation(context_);
    6.  
    7.   String local_ip_addr = IPAddrUtils.getIpAddress(context_);
    8.   Log.i(TAG, "initGB28181Agent local ip addr: " + local_ip_addr);
    9.  
    10.   if ( local_ip_addr == null || local_ip_addr.isEmpty() ) {
    11.     Log.e(TAG, "initGB28181Agent local ip is empty");
    12.     return  false;
    13.   }
    14.  
    15.   gb28181_agent_ = GBSIPAgentFactory.getInstance().create();
    16.   if ( gb28181_agent_ == null ) {
    17.     Log.e(TAG, "initGB28181Agent create agent failed");
    18.     return false;
    19.   }
    20.  
    21.   gb28181_agent_.addListener(this);
    22.  
    23.   // 必填信息
    24.   gb28181_agent_.setLocalAddressInfo(local_ip_addr, gb28181_sip_local_port_);
    25.   gb28181_agent_.setServerParameter(gb28181_sip_server_addr_, gb28181_sip_server_port_, gb28181_sip_server_id_, gb28181_sip_domain_);
    26.   gb28181_agent_.setUserInfo(gb28181_sip_username_, gb28181_sip_password_);
    27.  
    28.   // 可选参数
    29.   gb28181_agent_.setUserAgent(gb28181_sip_user_agent_filed_);
    30.   gb28181_agent_.setTransportProtocol(gb28181_sip_trans_protocol_==0?"UDP":"TCP");
    31.  
    32.   // GB28181配置
    33.   gb28181_agent_.config(gb28181_reg_expired_, gb28181_heartbeat_interval_, gb28181_heartbeat_count_);
    34.  
    35.   com.gb28181.ntsignalling.Device gb_device = new com.gb28181.ntsignalling.Device("34020000001380000001", "安卓测试设备", Build.MANUFACTURER, Build.MODEL,
    36.                                                                                   "宇宙","火星1","火星", true);
    37.  
    38.   if (mLongitude != null && mLatitude != null) {
    39.     com.gb28181.ntsignalling.DevicePosition device_pos = new com.gb28181.ntsignalling.DevicePosition();
    40.  
    41.     device_pos.setTime(mLocationTime);
    42.     device_pos.setLongitude(mLongitude);
    43.     device_pos.setLatitude(mLatitude);
    44.     gb_device.setPosition(device_pos);
    45.  
    46.     gb_device.setSupportMobilePosition(true); // 设置支持移动位置上报
    47.   }
    48.  
    49.   gb28181_agent_.addDevice(gb_device);
    50.  
    51.   if (!gb28181_agent_.initialize()) {
    52.     gb28181_agent_ = null;
    53.     Log.e(TAG, "initGB28181Agent gb28181_agent_.initialize failed.");
    54.     return  false;
    55.   }
    56.  
    57.   return true;
    58. }

    参数设定后，开始发送Regiter到平台端，Android设备端，针对Register的处理如下：

    1. @Override
    2. public void ntsRegisterOK(String dateString) {
    3.   Log.i(TAG, "ntsRegisterOK Date: " + (dateString!= null? dateString : ""));
    4. }
    5.  
    6. @Override
    7. public void ntsRegisterTimeout() {
    8.   Log.e(TAG, "ntsRegisterTimeout");
    9. }
    10.  
    11. @Override
    12. public void ntsRegisterTransportError(String errorInfo) {
    13.   Log.e(TAG, "ntsRegisterTransportError error:" + (errorInfo != null?errorInfo :""));
    14. }

    Catalog不再赘述，我们看看Inite处理：

    1. @Override
    2. public void ntsOnInvitePlay(String deviceId, PlaySessionDescription session_des) {
    3.   handler_.postDelayed(new Runnable() {
    4.     @Override
    5.     public void run() {
    6.       MediaSessionDescription video_des = session_des_.getVideoDescription();
    7.       SDPRtpMapAttribute ps_rtpmap_attr = video_des.getPSRtpMapAttribute();
    8.  
    9.       Log.i(TAG,"ntsInviteReceived, device_id:" +device_id_+", is_tcp:" + video_des.isRTPOverTCP()
    10.             + " rtp_port:" + video_des.getPort() + " ssrc:" + video_des.getSSRC()
    11.             + " address_type:" + video_des.getAddressType() + " address:" + video_des.getAddress());
    12.  
    13.       // 可以先给信令服务器发送临时振铃响应
    14.       //sip_stack_android.respondPlayInvite(180, device_id_);
    15.  
    16.       long rtp_sender_handle = libPublisher.CreateRTPSender(0);
    17.       if ( rtp_sender_handle == 0 ) {
    18.         gb28181_agent_.respondPlayInvite(488, device_id_);
    19.         Log.i(TAG, "ntsInviteReceived CreateRTPSender failed, response 488, device_id:" + device_id_);
    20.         return;
    21.       }
    22.  
    23.       gb28181_rtp_payload_type_ = ps_rtpmap_attr.getPayloadType();
    24.  
    25.       libPublisher.SetRTPSenderTransportProtocol(rtp_sender_handle, video_des.isRTPOverUDP()?0:1);
    26.       libPublisher.SetRTPSenderIPAddressType(rtp_sender_handle, video_des.isIPv4()?0:1);
    27.       libPublisher.SetRTPSenderLocalPort(rtp_sender_handle, 0);
    28.       libPublisher.SetRTPSenderSSRC(rtp_sender_handle, video_des.getSSRC());
    29.       libPublisher.SetRTPSenderSocketSendBuffer(rtp_sender_handle, 2*1024*1024); // 设置到2M
    30.       libPublisher.SetRTPSenderClockRate(rtp_sender_handle, ps_rtpmap_attr.getClockRate());
    31.       libPublisher.SetRTPSenderDestination(rtp_sender_handle, video_des.getAddress(), video_des.getPort());
    32.  
    33.       if ( libPublisher.InitRTPSender(rtp_sender_handle) != 0 ) {
    34.         gb28181_agent_.respondPlayInvite(488, device_id_);
    35.         libPublisher.DestoryRTPSender(rtp_sender_handle);
    36.         return;
    37.       }
    38.  
    39.       int local_port = libPublisher.GetRTPSenderLocalPort(rtp_sender_handle);
    40.       if (local_port == 0) {
    41.         gb28181_agent_.respondPlayInvite(488, device_id_);
    42.         libPublisher.DestoryRTPSender(rtp_sender_handle);
    43.         return;
    44.       }
    45.  
    46.       Log.i(TAG,"get local_port:" + local_port);
    47.  
    48.       String local_ip_addr = IPAddrUtils.getIpAddress(context_);
    49.       gb28181_agent_.respondPlayInviteOK(device_id_,local_ip_addr, local_port);
    50.  
    51.       gb28181_rtp_sender_handle_ = rtp_sender_handle;
    52.     }
    53.  
    54.     private String device_id_;
    55.     private PlaySessionDescription session_des_;
    56.  
    57.     public Runnable set(String device_id, PlaySessionDescription session_des) {
    58.       this.device_id_ = device_id;
    59.       this.session_des_ = session_des;
    60.       return this;
    61.     }
    62.   }.set(deviceId, session_des),0);
    63. }

    Ack后，开始发送打包后的ps数据：

    1. @Override
    2. public void ntsOnAckPlay(String deviceId) {
    3.   handler_.postDelayed(new Runnable() {
    4.     @Override
    5.     public void run() {
    6.       Log.i(TAG,"ntsOnACKPlay, device_id:" +device_id_);
    7.  
    8.       if (!isRecording && !isRTSPPublisherRunning && !isPushingRtmp) {
    9.         InitAndSetConfig();
    10.       }
    11.  
    12.       libPublisher.SetGB28181RTPSender(publisherHandle, gb28181_rtp_sender_handle_, gb28181_rtp_payload_type_);
    13.       int startRet = libPublisher.StartGB28181MediaStream(publisherHandle);
    14.       if (startRet != 0) {
    15.  
    16.         if (!isRecording && !isRTSPPublisherRunning && !isPushingRtmp ) {
    17.           if (publisherHandle != 0) {
    18.             libPublisher.SmartPublisherClose(publisherHandle);
    19.             publisherHandle = 0;
    20.           }
    21.         }
    22.  
    23.         destoryRTPSender();
    24.  
    25.         Log.e(TAG, "Failed to start GB28181 service..");
    26.         return;
    27.       }
    28.  
    29.       if (!isRecording && !isRTSPPublisherRunning && !isPushingRtmp) {
    30.         if (pushType == 0 || pushType == 1) {
    31.           CheckInitAudioRecorder();    //enable pure video publisher..
    32.         }
    33.       }
    34.  
    35.       startLayerPostThread();
    36.  
    37.       isGB28181StreamRunning = true;
    38.     }
    39.  
    40.     private String device_id_;
    41.  
    42.     public Runnable set(String device_id) {
    43.       this.device_id_ = device_id;
    44.       return this;
    45.     }
    46.  
    47.   }.set(deviceId),0);
    48. }

    再看看位置订阅处理：

    1. @Override
    2.     public void ntsOnDevicePositionRequest(String deviceId, int interval) {
    3.         handler_.postDelayed(new Runnable() {
    4.             @Override
    5.             public void run() {
    6.                 getLocation(context_);
    7.  
    8.                 Log.v(TAG, "ntsOnDevicePositionRequest, deviceId:" + this.device_id_ + ", Longitude:" + mLongitude
    9.                         + ", Latitude:" + mLatitude + ", Time:" + mLocationTime);
    10.  
    11.  
    12.                 if (mLongitude != null && mLatitude != null) {
    13.                     com.gb28181.ntsignalling.DevicePosition device_pos = new com.gb28181.ntsignalling.DevicePosition();
    14.  
    15.                     device_pos.setTime(mLocationTime);
    16.                     device_pos.setLongitude(mLongitude);
    17.                     device_pos.setLatitude(mLatitude);
    18.  
    19.                     if (gb28181_agent_ != null ) {
    20.                         gb28181_agent_.updateDevicePosition(device_id_, device_pos);
    21.                     }
    22.                 }
    23.             }
    24.  
    25.             private String device_id_;
    26.             private int interval_;
    27.  
    28.             public Runnable set(String device_id, int interval) {
    29.                 this.device_id_ = device_id;
    30.                 this.interval_ = interval;
    31.                 return this;
    32.             }
    33.  
    34.         }.set(deviceId, interval),0);
    35.     }

    语音广播和语音对讲处理：

    1. @Override
    2. public void ntsOnNotifyBroadcastCommand(String fromUserName, String fromUserNameAtDomain, String sn, String sourceID, String targetID) {
    3.   handler_.postDelayed(new Runnable() {
    4.     @Override
    5.     public void run() {
    6.       Log.i(TAG, "ntsOnNotifyBroadcastCommand, fromUserName:"+ from_user_name_ + ", fromUserNameAtDomain:"+ from_user_name_at_domain_
    7.             + ", SN:" + sn_ + ", sourceID:" + source_id_ + ", targetID:" + target_id_);
    8.  
    9.       if (gb28181_agent_ != null ) {
    10.         gb28181_agent_.respondBroadcastCommand(from_user_name_, from_user_name_at_domain_,sn_,source_id_, target_id_, true);
    11.         btnGB28181AudioBroadcast.setText("收到GB28181语音广播通知");
    12.       }
    13.     }
    14.  
    15.     private String from_user_name_;
    16.     private String from_user_name_at_domain_;
    17.     private String sn_;
    18.     private String source_id_;
    19.     private String target_id_;
    20.  
    21.     public Runnable set(String from_user_name, String from_user_name_at_domain, String sn, String source_id, String target_id) {
    22.       this.from_user_name_ = from_user_name;
    23.       this.from_user_name_at_domain_ = from_user_name_at_domain;
    24.       this.sn_ = sn;
    25.       this.source_id_ = source_id;
    26.       this.target_id_ = target_id;
    27.       return this;
    28.     }
    29.  
    30.   }.set(fromUserName, fromUserNameAtDomain, sn, sourceID, targetID),0);
    31. }
    32.  
    33. @Override
    34. public void ntsOnAudioBroadcast(String commandFromUserName, String commandFromUserNameAtDomain, String sourceID, String targetID) {
    35.   handler_.postDelayed(new Runnable() {
    36.     @Override
    37.     public void run() {
    38.       Log.i(TAG, "ntsOnAudioBroadcastPlay, fromFromUserName:" + command_from_user_name_
    39.             + " FromUserNameAtDomain:" + command_from_user_name_at_domain_
    40.             + " sourceID:" + source_id_ + ", targetID:" + target_id_);
    41.  
    42.       stopAudioPlayer();
    43.       destoryRTPReceiver();
    44.  
    45.       if (gb28181_agent_ != null ) {
    46.         String local_ip_addr = IPAddrUtils.getIpAddress(context_);
    47.  
    48.         boolean is_tcp = true; // 考虑到跨网段, 默认用TCP传输rtp包
    49.         rtp_receiver_handle_ = lib_player_.CreateRTPReceiver(0);
    50.         if (rtp_receiver_handle_ != 0 ) {
    51.           lib_player_.SetRTPReceiverTransportProtocol(rtp_receiver_handle_, is_tcp?1:0);
    52.           lib_player_.SetRTPReceiverIPAddressType(rtp_receiver_handle_, 0);
    53.  
    54.           if (0 == lib_player_.CreateRTPReceiverSession(rtp_receiver_handle_, 0) ) {
    55.             int local_port = lib_player_.GetRTPReceiverLocalPort(rtp_receiver_handle_);
    56.             boolean ret = gb28181_agent_.inviteAudioBroadcast(command_from_user_name_,command_from_user_name_at_domain_,
    57.                                                               source_id_, target_id_, "IP4", local_ip_addr, local_port, is_tcp?"TCP/RTP/AVP":"RTP/AVP");
    58.  
    59.             if (!ret ) {
    60.               destoryRTPReceiver();
    61.               btnGB28181AudioBroadcast.setText("GB28181语音广播");
    62.             }
    63.             else {
    64.               btnGB28181AudioBroadcast.setText("GB28181语音广播呼叫中");
    65.             }
    66.           } else {
    67.             destoryRTPReceiver();
    68.             btnGB28181AudioBroadcast.setText("GB28181语音广播");
    69.           }
    70.         }
    71.       }
    72.     }
    73.  
    74.     private String command_from_user_name_;
    75.     private String command_from_user_name_at_domain_;
    76.     private String source_id_;
    77.     private String target_id_;
    78.  
    79.     public Runnable set(String command_from_user_name, String command_from_user_name_at_domain, String source_id, String target_id) {
    80.       this.command_from_user_name_ = command_from_user_name;
    81.       this.command_from_user_name_at_domain_ = command_from_user_name_at_domain;
    82.       this.source_id_ = source_id;
    83.       this.target_id_ = target_id;
    84.       return this;
    85.     }
    86.  
    87.   }.set(commandFromUserName, commandFromUserNameAtDomain, sourceID, targetID),0);
    88. }

    Bye处理如下：

    1. @Override
    2. public void ntsOnByePlay(String deviceId) {
    3.   handler_.postDelayed(new Runnable() {
    4.     @Override
    5.     public void run() {
    6.       Log.i(TAG, "ntsOnByePlay, stop GB28181 media stream, deviceId=" + device_id_);
    7.  
    8.       stopGB28181Stream();
    9.       destoryRTPSender();
    10.     }
    11.  
    12.     private String device_id_;
    13.  
    14.     public Runnable set(String device_id) {
    15.       this.device_id_ = device_id;
    16.       return this;
    17.     }
    18.  
    19.   }.set(deviceId),0);
    20. }

    考虑到篇幅有限，上面仅展示基础的处理，如各种异常情况处理等，可单独沟通我，获取相关demo。

    总的来说，GB/T 28181接入，资料相对全面，但是好多都是基于demo的验证，经不住推敲，如果要产品化，开发者还需要很长的路要走。 

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  • 原文地址：https://blog.csdn.net/renhui1112/article/details/126687389