GB28181学习（十七）——基于jrtplib实现tcp被动和主动发流

前言

GB/T28181-2022实时流的传输方式介绍：https://blog.csdn.net/www_dong/article/details/134255185

基于jrtplib实现tcp被动和主动收流介绍：https://blog.csdn.net/www_dong/article/details/134451387

本文主要介绍下级平台或设备发流功能，用于对接特定的SIP服务器或上级平台。

UDP发流

流程图

发送端流程：

• 初始化rtp参数；
• 裸流数据做PS复用；
• 组RTP包发送；

设计

1. 初始化rtp参数

int CUdp::InitRtp_()
{
	RTPSessionParams sessionParams;
	sessionParams.SetMinimumRTCPTransmissionInterval(10);
	sessionParams.SetOwnTimestampUnit(1.0 / 90000.0);
	sessionParams.SetAcceptOwnPackets(true);
	sessionParams.SetMaximumPacketSize(1450);

	RTPUDPv4TransmissionParams transParams;
	transParams.SetRTPSendBuffer(2*1024*1024);
	transParams.SetBindIP(m_ip);
	transParams.SetPortbase((uint16_t)m_port);

	if (0 != Create(sessionParams, &transParams))
	{
		return -1;
	}

	SetDefaultPayloadType((uint8_t)m_payload);
	SetDefaultTimestampIncrement(3600);
	SetDefaultMark(true);

	RTPIPv4Address addr(ntohl(inet_addr(m_ip), (uint16_t)m_port);
	if(0 != AddDestination(addr))
    {
		return -1;
	}

	return 0;
}

2. 流数据复用为PS

// 使用ireader开源库进行ps复用
// 初始化
CData2PS::CData2PS()
{
	struct ps_muxer_func_t func;
	func.alloc = Alloc;
	func.free = Free;
	func.write = Packet;
	m_ps = ps_muxer_create(&func, this);
	// TODO codecid待补充
	m_ps_stream = ps_muxer_add_stream(m_ps, PSI_STREAM_H264, nullptr, 0);
}


// 塞数据
int CData2PS::InputData(void* data, int len)
{
	if (!m_ps)
		return -1;

	uint64_t clock = time64_now();
	if (0 == m_ps_clock)
		m_ps_clock = clock;

	return ps_muxer_input(m_ps, m_ps_stream, 0, (clock - m_ps_clock) * 90, (clock - m_ps_clock) * 90, data, len);
}

3. 发送rtp包

// 调用jrtplib中SendPacket(data, len);接口发送数据

// 以下为SendPacket部分源码
// 主要流程:
// 1. 构建packet
// 2. 发送rtp数据
int RTPSession::SendPacket(const void *data,size_t len,
                uint8_t pt,bool mark,uint32_t timestampinc)
{
	int status;

	if (!created)
		return ERR_RTP_SESSION_NOTCREATED;
	
	BUILDER_LOCK
	if ((status = packetbuilder.BuildPacket(data,len,pt,mark,timestampinc)) < 0)
	{
		BUILDER_UNLOCK
		return status;
	}
	if ((status = SendRTPData(packetbuilder.GetPacket(),packetbuilder.GetPacketLength())) < 0)
	{
		BUILDER_UNLOCK
		return status;
	}
	BUILDER_UNLOCK
	
	SOURCES_LOCK
	sources.SentRTPPacket();
	SOURCES_UNLOCK
	PACKSENT_LOCK
	sentpackets = true;
	PACKSENT_UNLOCK
	return 0;
}

// 构建包
int RTPPacketBuilder::PrivateBuildPacket(const void *data,size_t len,
	                  uint8_t pt,bool mark,uint32_t timestampinc,bool gotextension,
	                  uint16_t hdrextID,const void *hdrextdata,size_t numhdrextwords)
{
	RTPPacket p(pt,data,len,seqnr,timestamp,ssrc,mark,numcsrcs,csrcs,gotextension,hdrextID,
	            (uint16_t)numhdrextwords,hdrextdata,buffer,maxpacksize,GetMemoryManager());
	int status = p.GetCreationError();

	if (status < 0)
		return status;
	packetlength = p.GetPacketLength();

	if (numpackets == 0) // first packet
	{
		lastwallclocktime = RTPTime::CurrentTime();
		lastrtptimestamp = timestamp;
		prevrtptimestamp = timestamp;
	}
	else if (timestamp != prevrtptimestamp)
	{
		lastwallclocktime = RTPTime::CurrentTime();
		lastrtptimestamp = timestamp;
		prevrtptimestamp = timestamp;
	}
	
	numpayloadbytes += (uint32_t)p.GetPayloadLength();
	numpackets++;
	timestamp += timestampinc;
	seqnr++;

	return 0;
}

// 发送包
int RTPSession::SendRTPData(const void *data, size_t len)
{
	if (!m_changeOutgoingData)
		return rtptrans->SendRTPData(data, len);

	void *pSendData = 0;
	size_t sendLen = 0;
	int status = 0;

	status = OnChangeRTPOrRTCPData(data, len, true, &pSendData, &sendLen);
	if (status < 0)
		return status;

	if (pSendData)
	{
		status = rtptrans->SendRTPData(pSendData, sendLen);
		OnSentRTPOrRTCPData(pSendData, sendLen, true);
	}

	return status;
}

// 底层实现
int RTPUDPv4Transmitter::SendRTPData(const void *data,size_t len)	
{
	if (!init)
		return ERR_RTP_UDPV4TRANS_NOTINIT;

	MAINMUTEX_LOCK
	
	if (!created)
	{
		MAINMUTEX_UNLOCK
		return ERR_RTP_UDPV4TRANS_NOTCREATED;
	}
	if (len > maxpacksize)
	{
		MAINMUTEX_UNLOCK
		return ERR_RTP_UDPV4TRANS_SPECIFIEDSIZETOOBIG;
	}
	
	destinations.GotoFirstElement();
	while (destinations.HasCurrentElement())
	{
        // 调用sendto函数实现udp包的发送
		sendto(rtpsock,(const char *)data,len,0,(const struct sockaddr *)destinations.GetCurrentElement().GetRTPSockAddr(),sizeof(struct sockaddr_in));
		destinations.GotoNextElement();
	}
	
	MAINMUTEX_UNLOCK
	return 0;
}

tcp passive发流

流程图

发送端流程：

• 上级平台或sip服务器以主动方式连接，对于下级平台或者设备（数据发送端）为被动方式；
• 下级平台或者设备（数据发送端）启动端口监听；
• 接收上级平台或sip服务器tcp连接请求；
• 向上级平台或sip服务器发送流数据；

设计

1. 创建socket、bind、listen，启动数据接收线程；

// TcpServer为封装的socket类

int CGBTcpServer::Start()
{
	if (0 != m_localPort || m_tcpServer.get())
		return 0;

	int ret = -1;
	do 
	{
		m_tcpServer = std::make_shared<TcpServer>(nullptr, this);
		if (!m_tcpServer.get())
			break;

		ret = m_tcpServer->TcpCreate();
		if (0 != ret)
			break;

		ret = m_tcpServer->TcpBind(m_localPort);
		if (0 != ret)
			break;

		ret = m_tcpServer->TcpListen(5);
		if (0 != ret)
			break;

		m_thread = std::thread(TCPData2PSThread, this);
		return 0;
	} while (0);

	Stop();
	return ret;
}

2. 在线程内等待连接，连接成功后接收数据并回调至应用层处理

void CGBTcpServer::TCPData2PSWorker()
{
	if (!m_pspacker)
		m_pspacker = new(std::nothrow) CData2PS(PSTCPDataCB, this);

	bool bAccept = false;
	while (m_running)
	{
		if (!bAccept)
		{
			if (0 == m_tcpServer->TcpAccept())
			{
				bAccept = true;
				if (0 != InitRtp_())
				{
					break;
				}
			}

			continue;
		}

		std::this_thread::sleep_for(std::chrono::seconds(1));
	}
}

3. 初始化rtp参数

int CGBTcpServer::InitRtp_()
{
	const int packetSize = 45678;
	RTPSessionParams sessionparams;
	sessionparams.SetProbationType(RTPSources::NoProbation);
	sessionparams.SetOwnTimestampUnit(1.0 / packetSize);
	sessionparams.SetMaximumPacketSize(packetSize + 64);

	m_rtpTcpTransmitter = new RTPTCPTransmitter(nullptr);
	m_rtpTcpTransmitter->Init(true);
	m_rtpTcpTransmitter->Create(65535, 0);

	int status = Create(sessionparams, m_rtpTcpTransmitter);
	if (status < 0)
	{
		return status;
	}

	status = AddDestination(RTPTCPAddress(m_tcpServer->GetClientSocket()));
	if (0 != status)
		return status;

	SetDefaultPayloadType(96);
	SetDefaultMark(false);
	SetDefaultTimestampIncrement(160);
	return 0;
}

4. 将数据复用为PS；
5. tcp方式发包

// 调用jrtplib中SendPacket(data, len);接口发送数据

// 以下为tcp方式SendPacket部分源码
int RTPTCPTransmitter::SendRTPData(const void *data,size_t len)	
{
	return SendRTPRTCPData(data, len);
}

int RTPTCPTransmitter::SendRTPRTCPData(const void *data, size_t len)
{
	if (!m_init)
		return ERR_RTP_TCPTRANS_NOTINIT;

	MAINMUTEX_LOCK
	
	if (!m_created)
	{
		MAINMUTEX_UNLOCK
		return ERR_RTP_TCPTRANS_NOTCREATED;
	}
    
    // #define RTPTCPTRANS_MAXPACKSIZE							65535
	if (len > RTPTCPTRANS_MAXPACKSIZE)
	{
		MAINMUTEX_UNLOCK
		return ERR_RTP_TCPTRANS_SPECIFIEDSIZETOOBIG;
	}
	
	std::map<SocketType, SocketData>::iterator it = m_destSockets.begin();
	std::map<SocketType, SocketData>::iterator end = m_destSockets.end();

	vector<SocketType> errSockets;
	int flags = 0;
#ifdef RTP_HAVE_MSG_NOSIGNAL
	flags = MSG_NOSIGNAL;
#endif // RTP_HAVE_MSG_NOSIGNAL

	while (it != end)
	{
		uint8_t lengthBytes[2] = { (uint8_t)((len >> 8)&0xff), (uint8_t)(len&0xff) };
		SocketType sock = it->first;

        // 调用send接口发送数据
        // 1. 先发送2字节头(固定格式)
        // 2. 再发送数据
		if (send(sock,(const char *)lengthBytes,2,flags) < 0 ||
			send(sock,(const char *)data,len,flags) < 0)
			errSockets.push_back(sock);
		++it;
	}
	
	MAINMUTEX_UNLOCK

	if (errSockets.size() != 0)
	{
		for (size_t i = 0 ; i < errSockets.size() ; i++)
			OnSendError(errSockets[i]);
	}

	// Don't return an error code to avoid the poll thread exiting
	// due to one closed connection for example

	return 0;
}

tcp active发流

流程图

发送端流程：

• 上级平台或sip服务器启动tcp监听连接，对于下级平台或者设备（数据发送端）为主动方式；
• 下级平台或者设备（数据发送端）发起tcp连接；
• 接收上级平台或sip服务器tcp响应；
• 向上级平台或sip服务器发送流数据；

设计

1. 创建socket、connect、初始化rtp，启动数据接收线程

// TcpClient为封装的客户端socket类

int CGBTcpClient::Start()
{
	if (0 != m_localPort || m_tcpClient.get())
		return 0;

	int ret = -1;
	do
	{
		m_tcpClient = std::make_shared<TcpClient>(nullptr, this);
		if (!m_tcpClient.get() || 0 != m_tcpClient->TcpCreate())
			break;

		ret = m_tcpClient->TcpConnectByTime(m_localIP.c_str(), m_localPort, 5);
		if (0 != ret)
			break;

		ret = InitRtp_();
		if (0 != ret)
			break;

		m_thread = std::thread(RTPPackerThread, this);
		return 0;
	} while (0);

	Stop();
	return ret;
}

2. 初始化rtp参数

int CGBTcpClient::InitRtp_()
{
	const int packSize = 45678;
	RTPSessionParams sessionParams;
	sessionParams.SetProbationType(RTPSources::NoProbation);
	sessionParams.SetOwnTimestampUnit(90000.0 / 25.0);
	sessionParams.SetMaximumPacketSize(packSize + 64);

	m_rtpTcpTransmitter = new RTPTCPTransmitter(nullptr);
	m_rtpTcpTransmitter->Init(true);
	m_rtpTcpTransmitter->Create(65535, 0);

	if (0 != Create(sessionParams, m_rtpTcpTransmitter))
		return -1;

	if (0 != AddDestination(RTPTCPAddress(m_tcpClient->GetClientSocket())))
		return -1;

	return 0;
}

3. 视音频数据复用为PS
4. 发送数据，同tcp passive发流