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:
/*** GB28181 相关参数,可以修改相关参数后测试 ***/GBSIPAgent gb28181_agent_ = null;private int gb28181_sip_local_port_ = 12070;private String gb28181_sip_server_id_ = "34020000002000000001";private String gb28181_sip_domain_ = "3402000000";private String gb28181_sip_server_addr_ = "192.168.0.105";private int gb28181_sip_server_port_ = 15060;private String gb28181_sip_user_agent_filed_ = "NT GB28181 User Agent V1.2";private String gb28181_sip_username_ = "31011500991320000069";private String gb28181_sip_password_ = "12345678";private int gb28181_reg_expired_ = 3600; // 注册有效期时间最小3600秒private int gb28181_heartbeat_interval_ = 20; // 心跳间隔GB28181默认是60, 目前调整到20秒private int gb28181_heartbeat_count_ = 3; // 心跳间隔3次失败,表示和服务器断开了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private long gb28181_rtp_sender_handle_ = 0;private int gb28181_rtp_payload_type_ = 96;private long player_handle_ = 0;private long rtp_receiver_handle_ = 0;private AtomicLong last_received_audio_data_time_ = new AtomicLong(0);/*** 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:
/** Github: https://github.com/daniulive/SmarterStreaming*/
class ButtonGB28181AgentListener implements OnClickListener {public void onClick(View v) {stopAudioPlayer();destoryRTPReceiver();gb_broadcast_source_id_ = null;gb_broadcast_target_id_ = null;btnGB28181AudioBroadcast.setText("GB28181语音广播");btnGB28181AudioBroadcast.setEnabled(false);stopGB28181Stream();destoryRTPSender();if (null == gb28181_agent_ ) {if( !initGB28181Agent() )return;}if (gb28181_agent_.isRunning()) {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gb28181_agent_.stop();btnGB28181Agent.setText("启动GB28181");}else {if ( gb28181_agent_.start() ) {btnGB28181Agent.setText("停止GB28181");}}}
}
其中,initGB2818Agent()主要是基础参数设置,对应的实现如下:
private boolean initGB28181Agent() {if ( gb28181_agent_ != null )return true;getLocation(context_);String local_ip_addr = IPAddrUtils.getIpAddress(context_);Log.i(TAG, "initGB28181Agent local ip addr: " + local_ip_addr);if ( local_ip_addr == null || local_ip_addr.isEmpty() ) {Log.e(TAG, "initGB28181Agent local ip is empty");return false;}gb28181_agent_ = GBSIPAgentFactory.getInstance().create();if ( gb28181_agent_ == null ) {Log.e(TAG, "initGB28181Agent create agent failed");return false;}gb28181_agent_.addListener(this);// 必填信息gb28181_agent_.setLocalAddressInfo(local_ip_addr, gb28181_sip_local_port_);gb28181_agent_.setServerParameter(gb28181_sip_server_addr_, gb28181_sip_server_port_, gb28181_sip_server_id_, gb28181_sip_domain_);gb28181_agent_.setUserInfo(gb28181_sip_username_, gb28181_sip_password_);// 可选参数gb28181_agent_.setUserAgent(gb28181_sip_user_agent_filed_);gb28181_agent_.setTransportProtocol(gb28181_sip_trans_protocol_==0?"UDP":"TCP");// GB28181配置gb28181_agent_.config(gb28181_reg_expired_, gb28181_heartbeat_interval_, gb28181_heartbeat_count_);com.gb28181.ntsignalling.Device gb_device = new com.gb28181.ntsignalling.Device("34020000001380000001", "安卓测试设备", Build.MANUFACTURER, Build.MODEL,"宇宙","火星1","火星", true);if (mLongitude != null && mLatitude != null) {com.gb28181.ntsignalling.DevicePosition device_pos = new com.gb28181.ntsignalling.DevicePosition();device_pos.setTime(mLocationTime);device_pos.setLongitude(mLongitude);device_pos.setLatitude(mLatitude);gb_device.setPosition(device_pos);gb_device.setSupportMobilePosition(true); // 设置支持移动位置上报}gb28181_agent_.addDevice(gb_device);if (!gb28181_agent_.initialize()) {gb28181_agent_ = null;Log.e(TAG, "initGB28181Agent gb28181_agent_.initialize failed.");return false;}return true;
}
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:
@Override
public void ntsRegisterOK(String dateString) {Log.i(TAG, "ntsRegisterOK Date: " + (dateString!= null? dateString : ""));
}@Override
public void ntsRegisterTimeout() {Log.e(TAG, "ntsRegisterTimeout");
}@Override
public void ntsRegisterTransportError(String errorInfo) {Log.e(TAG, "ntsRegisterTransportError error:" + (errorInfo != null?errorInfo :""));
}
Catalog不再赘述,我们看看Inite处理:
@Override
public void ntsOnInvitePlay(String deviceId, PlaySessionDescription session_des) {handler_.postDelayed(new Runnable() {@Overridepublic void run() {MediaSessionDescription video_des = session_des_.getVideoDescription();SDPRtpMapAttribute ps_rtpmap_attr = video_des.getPSRtpMapAttribute();Log.i(TAG,"ntsInviteReceived, device_id:" +device_id_+", is_tcp:" + video_des.isRTPOverTCP()+ " rtp_port:" + video_des.getPort() + " ssrc:" + video_des.getSSRC()+ " address_type:" + video_des.getAddressType() + " address:" + video_des.getAddress());// 可以先给信令服务器发送临时振铃响应//sip_stack_android.respondPlayInvite(180, device_id_);long rtp_sender_handle = libPublisher.CreateRTPSender(0);if ( rtp_sender_handle == 0 ) {gb28181_agent_.respondPlayInvite(488, device_id_);Log.i(TAG, "ntsInviteReceived CreateRTPSender failed, response 488, device_id:" + device_id_);return;}gb28181_rtp_payload_type_ = ps_rtpmap_attr.getPayloadType();libPublisher.SetRTPSenderTransportProtocol(rtp_sender_handle, video_des.isRTPOverUDP()?0:1);libPublisher.SetRTPSenderIPAddressType(rtp_sender_handle, video_des.isIPv4()?0:1);libPublisher.SetRTPSenderLocalPort(rtp_sender_handle, 0);libPublisher.SetRTPSenderSSRC(rtp_sender_handle, video_des.getSSRC());libPublisher.SetRTPSenderSocketSendBuffer(rtp_sender_handle, 2*1024*1024); // 设置到2MlibPublisher.SetRTPSenderClockRate(rtp_sender_handle, ps_rtpmap_attr.getClockRate());libPublisher.SetRTPSenderDestination(rtp_sender_handle, video_des.getAddress(), video_des.getPort());if ( libPublisher.InitRTPSender(rtp_sender_handle) != 0 ) {gb28181_agent_.respondPlayInvite(488, device_id_);libPublisher.DestoryRTPSender(rtp_sender_handle);return;}int local_port = libPublisher.GetRTPSenderLocalPort(rtp_sender_handle);if (local_port == 0) {gb28181_agent_.respondPlayInvite(488, device_id_);libPublisher.DestoryRTPSender(rtp_sender_handle);return;}Log.i(TAG,"get local_port:" + local_port);String local_ip_addr = IPAddrUtils.getIpAddress(context_);gb28181_agent_.respondPlayInviteOK(device_id_,local_ip_addr, local_port);gb28181_rtp_sender_handle_ = rtp_sender_handle;}private String device_id_;private PlaySessionDescription session_des_;public Runnable set(String device_id, PlaySessionDescription session_des) {this.device_id_ = device_id;this.session_des_ = session_des;return this;}}.set(deviceId, session_des),0);
}
Ack后,开始发送打包后的ps数据:
@Override
public void ntsOnAckPlay(String deviceId) {handler_.postDelayed(new Runnable() {@Overridepublic void run() {Log.i(TAG,"ntsOnACKPlay, device_id:" +device_id_);if (!isRecording && !isRTSPPublisherRunning && !isPushingRtmp) {InitAndSetConfig();}libPublisher.SetGB28181RTPSender(publisherHandle, gb28181_rtp_sender_handle_, gb28181_rtp_payload_type_);int startRet = libPublisher.StartGB28181MediaStream(publisherHandle);if (startRet != 0) {if (!isRecording && !isRTSPPublisherRunning && !isPushingRtmp ) {if (publisherHandle != 0) {libPublisher.SmartPublisherClose(publisherHandle);publisherHandle = 0;}}destoryRTPSender();Log.e(TAG, "Failed to start GB28181 service..");return;}if (!isRecording && !isRTSPPublisherRunning && !isPushingRtmp) {if (pushType == 0 || pushType == 1) {CheckInitAudioRecorder(); //enable pure video publisher..}}startLayerPostThread();isGB28181StreamRunning = true;}private String device_id_;public Runnable set(String device_id) {this.device_id_ = device_id;return this;}}.set(deviceId),0);
}
再看看位置订阅处理:
@Overridepublic void ntsOnDevicePositionRequest(String deviceId, int interval) {handler_.postDelayed(new Runnable() {@Overridepublic void run() {getLocation(context_);Log.v(TAG, "ntsOnDevicePositionRequest, deviceId:" + this.device_id_ + ", Longitude:" + mLongitude+ ", Latitude:" + mLatitude + ", Time:" + mLocationTime);if (mLongitude != null && mLatitude != null) {com.gb28181.ntsignalling.DevicePosition device_pos = new com.gb28181.ntsignalling.DevicePosition();device_pos.setTime(mLocationTime);device_pos.setLongitude(mLongitude);device_pos.setLatitude(mLatitude);if (gb28181_agent_ != null ) {gb28181_agent_.updateDevicePosition(device_id_, device_pos);}}}private String device_id_;private int interval_;public Runnable set(String device_id, int interval) {this.device_id_ = device_id;this.interval_ = interval;return this;}}.set(deviceId, interval),0);}
语音广播和语音对讲处理:
@Override
public void ntsOnNotifyBroadcastCommand(String fromUserName, String fromUserNameAtDomain, String sn, String sourceID, String targetID) {handler_.postDelayed(new Runnable() {@Overridepublic void run() {Log.i(TAG, "ntsOnNotifyBroadcastCommand, fromUserName:"+ from_user_name_ + ", fromUserNameAtDomain:"+ from_user_name_at_domain_+ ", SN:" + sn_ + ", sourceID:" + source_id_ + ", targetID:" + target_id_);if (gb28181_agent_ != null ) {gb28181_agent_.respondBroadcastCommand(from_user_name_, from_user_name_at_domain_,sn_,source_id_, target_id_, true);btnGB28181AudioBroadcast.setText("收到GB28181语音广播通知");}}private String from_user_name_;private String from_user_name_at_domain_;private String sn_;private String source_id_;private String target_id_;public Runnable set(String from_user_name, String from_user_name_at_domain, String sn, String source_id, String target_id) {this.from_user_name_ = from_user_name;this.from_user_name_at_domain_ = from_user_name_at_domain;this.sn_ = sn;this.source_id_ = source_id;this.target_id_ = target_id;return this;}}.set(fromUserName, fromUserNameAtDomain, sn, sourceID, targetID),0);
}@Override
public void ntsOnAudioBroadcast(String commandFromUserName, String commandFromUserNameAtDomain, String sourceID, String targetID) {handler_.postDelayed(new Runnable() {@Overridepublic void run() {Log.i(TAG, "ntsOnAudioBroadcastPlay, fromFromUserName:" + command_from_user_name_+ " FromUserNameAtDomain:" + command_from_user_name_at_domain_+ " sourceID:" + source_id_ + ", targetID:" + target_id_);stopAudioPlayer();destoryRTPReceiver();if (gb28181_agent_ != null ) {String local_ip_addr = IPAddrUtils.getIpAddress(context_);boolean is_tcp = true; // 考虑到跨网段, 默认用TCP传输rtp包rtp_receiver_handle_ = lib_player_.CreateRTPReceiver(0);if (rtp_receiver_handle_ != 0 ) {lib_player_.SetRTPReceiverTransportProtocol(rtp_receiver_handle_, is_tcp?1:0);lib_player_.SetRTPReceiverIPAddressType(rtp_receiver_handle_, 0);if (0 == lib_player_.CreateRTPReceiverSession(rtp_receiver_handle_, 0) ) {int local_port = lib_player_.GetRTPReceiverLocalPort(rtp_receiver_handle_);boolean ret = gb28181_agent_.inviteAudioBroadcast(command_from_user_name_,command_from_user_name_at_domain_,source_id_, target_id_, "IP4", local_ip_addr, local_port, is_tcp?"TCP/RTP/AVP":"RTP/AVP");if (!ret ) {destoryRTPReceiver();btnGB28181AudioBroadcast.setText("GB28181语音广播");}else {btnGB28181AudioBroadcast.setText("GB28181语音广播呼叫中");}} else {destoryRTPReceiver();btnGB28181AudioBroadcast.setText("GB28181语音广播");}}}}private String command_from_user_name_;private String command_from_user_name_at_domain_;private String source_id_;private String target_id_;public Runnable set(String command_from_user_name, String command_from_user_name_at_domain, String source_id, String target_id) {this.command_from_user_name_ = command_from_user_name;this.command_from_user_name_at_domain_ = command_from_user_name_at_domain;this.source_id_ = source_id;this.target_id_ = target_id;return this;}}.set(commandFromUserName, commandFromUserNameAtDomain, sourceID, targetID),0);
}
Bye处理如下:
@Override
public void ntsOnByePlay(String deviceId) {handler_.postDelayed(new Runnable() {@Overridepublic void run() {Log.i(TAG, "ntsOnByePlay, stop GB28181 media stream, deviceId=" + device_id_);stopGB28181Stream();destoryRTPSender();}private String device_id_;public Runnable set(String device_id) {this.device_id_ = device_id;return this;}}.set(deviceId),0);
}
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。