jrtplib开源库系列之二:jrtplib库example1分析说明

源代码

void checkerror(int rtperr)
{
	if (rtperr < 0)
	{
		std::cout << "ERROR: " << RTPGetErrorString(rtperr) << std::endl;
		exit(-1);
	}
}
//
// The main routine
//
int main(void)
{
#ifdef RTP_SOCKETTYPE_WINSOCK
	WSADATA dat;
	WSAStartup(MAKEWORD(2,2),&dat);
#endif // RTP_SOCKETTYPE_WINSOCK
	
	RTPSession sess;
	uint16_t portbase,destport;
	uint32_t destip;
	std::string ipstr;
	int status,i,num;

	std::cout << "Using version " << RTPLibraryVersion::GetVersion().GetVersionString() << std::endl;

	// First, we'll ask for the necessary information
		
	std::cout << "Enter local portbase:" << std::endl;
	std::cin >> portbase; //设置端口
	std::cout << std::endl;
	
	std::cout << "Enter the destination IP address" << std::endl;
	std::cin >> ipstr;
	destip = inet_addr(ipstr.c_str());
	if (destip == INADDR_NONE)
	{
		std::cerr << "Bad IP address specified" << std::endl;
		return -1;
	}
	
	// The inet_addr function returns a value in network byte order, but
	// we need the IP address in host byte order, so we use a call to
	// ntohl
	destip = ntohl(destip);//转换为主机地址序
	
	std::cout << "Enter the destination port" << std::endl;
	std::cin >> destport;//设置目的地址的端口，如果测试自己给自己发送的包，请和portbase设置一致
	std::cout << std::endl;
	std::cout << "Number of packets you wish to be sent:" << std::endl;
	std::cin >> num;
	// Now, we'll create a RTP session, set the destination, send some
	// packets and poll for incoming data.
	
	RTPUDPv4TransmissionParams transparams;
	RTPSessionParams sessparams;
	
	// IMPORTANT: The local timestamp unit MUST be set, otherwise
	//            RTCP Sender Report info will be calculated wrong
	// In this case, we'll be sending 10 samples each second, so we'll
	// put the timestamp unit to (1.0/10.0)
	//在其他应用中，必须设置这个参数，比如使用RTP协议传输H264,这里必须设置为1/90000，关于如何使用RTP传输H264，请参考RFC3984协议规范
	sessparams.SetOwnTimestampUnit(1.0/10.0);	
	
	sessparams.SetAcceptOwnPackets(true);//注意，如果想测试自己调用自己发送的包，需要设置为true
	transparams.SetPortbase(portbase);
	status = sess.Create(sessparams,&transparams);	
	checkerror(status);
	
	RTPIPv4Address addr(destip,destport);
	
	status = sess.AddDestination(addr);
	checkerror(status);
	
	for(int i = 0; i < num; ++i)
	{
		
		// send the packet
		status = sess.SendPacket((void *)"1234567890",10,0,false,10);
       checkerror(status);
		
	   //由于可能使用多线程，需要保证数据源数据在多线程下是安全的
	   //用户在获取其他数据源发送数据之前需要调用这个接口
	   //在调用完成之后需要调用EndDataAccess()接口
		sess.BeginDataAccess();
		
		// check incoming packets
		if (sess.GotoFirstSourceWithData()) //判断是否有其他数据源发送的数据
		{
			do
			{
				RTPPacket *pack;
				
				while ((pack = sess.GetNextPacket()) != NULL)
				{
					// You can examine the data here
					printf("Got packet !\n");
					
					// we don't longer need the packet, so
					// we'll delete it
					sess.DeletePacket(pack);
				}
			} while (sess.GotoNextSourceWithData());
		}
		sess.EndDataAccess();//由于可能使用多线程，需要保证数据源数据在多线程下是安全的

#ifndef RTP_SUPPORT_THREAD
		status = sess.Poll();
		checkerror(status);
#endif // RTP_SUPPORT_THREAD
		
		RTPTime::Wait(RTPTime(1,0));
	}
	sess.BYEDestroy(RTPTime(10,0),0,0);
#ifdef RTP_SOCKETTYPE_WINSOCK
	WSACleanup();
#endif // RTP_SOCKETTYPE_WINSOCK
	return 0;
}

代码说明

这个官方example还是比较简单的，主要是测试发一个数据包，然后自己接收发出的包，注意，这里需要注意将目的地址的端口和基端口(portbase)设置为相同，同时需要将这个参数设置为真sessparams.SetAcceptOwnPackets(true);