apps/astreamer/rtp_stream.cpp

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#include <arpa/inet.h>
#include <iostream>
#include "rtp_stream.h"
#include "helper.h"

using namespace std;

#define CNAME "elphel353"

#undef RTP_DEBUG
//#define RTP_DEBUG

#ifdef RTP_DEBUG
        #define D(a) a
#else
        #define D(a)
#endif


int RTP_Stream::_fd = -1;

RTP_Stream::RTP_Stream(void) {
        _play = false;
        pthread_mutex_init(&pthm_flow, NULL);
        stream_name = "unknown";
}

void RTP_Stream::init_pthread(void *__this) {
        pth_id = pthread_create(&pth, NULL, RTP_Stream::pthread_f, (void *)__this);
}

void *RTP_Stream::pthread_f(void *_this) {
        RTP_Stream *__this = (RTP_Stream *)_this;
        return __this->thread();
}

void RTP_Stream::Start(string ip, int port) {
D(cerr << " new " << stream_name << " UDP socket at port: " << port << endl;)
        rtp_socket = new Socket(ip, port, Socket::TYPE_UDP);
        rtcp_socket = new Socket(ip, port + 1, Socket::TYPE_UDP);
        rtp_packets = 0;
        rtp_octets = 0;
        rtcp_tv.tv_sec = 0;
        rtcp_tv.tv_usec = 0;
        rtcp_delay = 1000000;
        _play = true;
}

void RTP_Stream::Stop(void) {
D(cerr << __FILE__<< ":"<< __FUNCTION__ << ":" <<__LINE__ <<endl;)
        pthread_mutex_lock(&pthm_flow);
        _play = false;
//      delete rtcp_socket;
        delete rtp_socket;
        pthread_mutex_unlock(&pthm_flow);
}

void *RTP_Stream::thread(void) {
D(      cerr << "RTP_Stream::thread(void)" <<endl;)
        for(;;) {
                if(_play) {
                        pthread_mutex_lock(&pthm_flow);
                        long f = 0;
                        if(_play) {
                                f = process();
                        }
                        if(f>0)
                                rtcp();
                        pthread_mutex_unlock(&pthm_flow);
                        if (f<0) {
D(  cerr << __FILE__<< ":"<< __FUNCTION__ << ":" <<__LINE__<< "process exception detected: " << f << endl;)
                          Stop();
                        }
                } else
                        sched_yield();
        }
        return NULL;
}

void RTP_Stream::rtcp(void) {
        // check time for next one RTCP...
        if(f_tv.tv_sec == 0 && f_tv.tv_usec == 0)
                return;
        long td = time_delta_us(f_tv, rtcp_tv);
        if(td < 0) {
                rtcp_tv = f_tv;
                return;
        }
        if(td < rtcp_delay)
                return;
        rtcp_tv = f_tv;
        rtcp_send_sdes();
        rtcp_send_sr();
}

void RTP_Stream::rtcp_send_sr(void) {
        char packet[8 + 20]; // by RTP RFC 3550, for SR RTCP packet needed 8 + 20 bytes
        int packet_len = sizeof(packet);
        unsigned short us;
        unsigned long ul;

        // RTCP header
        packet[0] = 0x81;
        packet[1] = 200;
        us = htons(((packet_len) / 4) - 1);
        memcpy((void *)&packet[2], (void *)&us, 2);
        memcpy((void *)&packet[4], (void *)&SSRC, 4);
        // SR
char buf[64];
sprintf(buf, "%d:%06d", (int) f_tv.tv_sec, (int) f_tv.tv_usec);
        ul = htonl(f_tv.tv_sec);
        memcpy((void *)&packet[8], (void *)&ul, 4);
        ul = htonl(f_tv.tv_usec);
        memcpy((void *)&packet[12], (void *)&ul, 4);
        ul = htonl(timestamp);
        memcpy((void *)&packet[16], (void *)&ul, 4);
        ul = htonl(rtp_packets);
        memcpy((void *)&packet[20], (void *)&ul, 4);
        ul = htonl(rtp_octets);
        memcpy((void *)&packet[24], (void *)&ul, 4);
        rtcp_socket->send(packet, packet_len);
//cerr << "stream: " << stream_name << "; send SR; timestamp == " << timestamp << "; sync CLOCK == " << buf << endl;
        // fresh statistically information
//      rtp_packets = 0;
//      rtp_octets = 0;
}

void RTP_Stream::rtcp_send_sdes(void) {
        char packet[8 + 4 + 128]; // by RTP RFC 3550, for SDES RTCP packet needed 8 + 4 + ... bytes, so get additional 128 bytes for 126 CNAME field
        int packet_len = 0;

        unsigned short us;
        const char *cname = CNAME;
        int cname_len = strlen(cname);
        // RTCP header
        packet[0] = 0x81;
        packet[1] = 202;
        memcpy((void *)&packet[4], (void *)&SSRC, 4);
        packet_len += 8;
        // SDES fields
        packet[8] = 0x01;
        packet[9] = cname_len;
        memcpy((void *)&packet[10], (void *)cname, cname_len);
        packet_len += 2 + cname_len;
        us = htons((packet_len / 4) - 1);
        memcpy((void *)&packet[2], (void *)&us, 2);

        rtcp_socket->send(packet, packet_len);
}

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