srt学习笔记五：手写个srt的socket

参考：https://www.jianshu.com/p/3957c55a702d

实时模式用于传送实时多媒体流。

实时模式下，数据分片（默认是1316 = 7 * 188,188是单个MPEG TS大小）在一定的速率控制下发出，并且在接收端按照发送端发送的时间间隔重新组织好。

默认情况下，接收端重组会有一定的时延，默认为120ms。




参考
https://github.com/Haivision/srt/blob/master/examples/test-c-server.c
和
https://github.com/Haivision/srt/blob/master/examples/test-c-client.c

test-c-server.c

#include <stdio.h>
#include <stdlib.h>
#include "srt/srt.h"
int main(int argc, char** argv)
{
    int ss, st;
    struct sockaddr_in sa;
    int yes = 1;
    struct sockaddr_storage their_addr;

    if (argc != 3) {
      fprintf(stderr, "Usage: %s <host> <port>\n", argv[0]);
      return 1;
    }

    printf("srt startup\n");
    srt_startup();

    printf("srt socket\n");
    ss = srt_create_socket();
    if (ss == SRT_ERROR)
    {
        fprintf(stderr, "srt_socket: %s\n", srt_getlasterror_str());
        return 1;
    }

    printf("srt bind address\n");
    sa.sin_family = AF_INET;
    sa.sin_port = htons(atoi(argv[2]));
    if (inet_pton(AF_INET, argv[1], &sa.sin_addr) != 1)
    {
        return 1;
    }

    printf("srt setsockflag\n");
    srt_setsockflag(ss, SRTO_RCVSYN, &yes, sizeof yes);

    printf("srt bind\n");
    st = srt_bind(ss, (struct sockaddr*)&sa, sizeof sa);
    if (st == SRT_ERROR)
    {
        fprintf(stderr, "srt_bind: %s\n", srt_getlasterror_str());
        return 1;
    }

    printf("srt listen\n");
    st = srt_listen(ss, 2);
    if (st == SRT_ERROR)
    {
        fprintf(stderr, "srt_listen: %s\n", srt_getlasterror_str());
        return 1;
    }

    printf("srt accept\n");
    int addr_size = sizeof their_addr;
    int their_fd = srt_accept(ss, (struct sockaddr *)&their_addr, &addr_size);

    int i;
    for (i = 0; i < 100; i++)
    {
        printf("srt recvmsg #%d... ",i);
        char msg[2048];
        st = srt_recvmsg(their_fd, msg, sizeof msg);
        if (st == SRT_ERROR)
        {
            fprintf(stderr, "srt_recvmsg: %s\n", srt_getlasterror_str());
            goto end;
        }

        printf("Got msg of len %d << %s\n", st, msg);
    }

end:
    printf("srt close\n");
    st = srt_close(ss);
    if (st == SRT_ERROR)
    {
        fprintf(stderr, "srt_close: %s\n", srt_getlasterror_str());
        return 1;
    }

    printf("srt cleanup\n");
    srt_cleanup();
    return 0;
}

test-c-client.c

#include <stdio.h>
#include <stdlib.h>
#ifdef _WIN32
#define usleep(x) Sleep(x / 1000)
#else
#include <unistd.h>
#endif
#include "srt/srt.h"
int main(int argc, char** argv)
{
    int ss, st;
    struct sockaddr_in sa;
    int yes = 1;
    const char message [] = "This message should be sent to the other side";

    if (argc != 3) {
      fprintf(stderr, "Usage: %s <host> <port>\n", argv[0]);
      return 1;
    }
    printf("srt startup\n");
    srt_startup();

    printf("srt socket\n");
    ss = srt_create_socket();
    if (ss == SRT_ERROR)
    {
        fprintf(stderr, "srt_socket: %s\n", srt_getlasterror_str());
        return 1;
    }
    printf("srt remote address\n");
    sa.sin_family = AF_INET;
    sa.sin_port = htons(atoi(argv[2]));
    if (inet_pton(AF_INET, argv[1], &sa.sin_addr) != 1)
    {
        return 1;
    }
    printf("srt setsockflag\n");
    srt_setsockflag(ss, SRTO_SENDER, &yes, sizeof yes);
    // Test deprecated
    //srt_setsockflag(ss, SRTO_STRICTENC, &yes, sizeof yes);
    printf("srt connect\n");
    st = srt_connect(ss, (struct sockaddr*)&sa, sizeof sa);
    if (st == SRT_ERROR)
    {
        fprintf(stderr, "srt_connect: %s\n", srt_getlasterror_str());
        return 1;
    }

    int i;
    for (i = 0; i < 100; i++)
    {
        printf("srt sendmsg2 #%d >> %s\n",i,message);
        st = srt_sendmsg2(ss, message, sizeof message, NULL);
        if (st == SRT_ERROR)
        {
            fprintf(stderr, "srt_sendmsg: %s\n", srt_getlasterror_str());
            return 1;
        }

        usleep(1000);   // 1 ms
    }


    printf("srt close\n");
    st = srt_close(ss);
    if (st == SRT_ERROR)
    {
        fprintf(stderr, "srt_close: %s\n", srt_getlasterror_str());
        return 1;
    }

    printf("srt cleanup\n");
    srt_cleanup();
    return 0;
}

#gcc -std=c99 -lsrt testcserver.c -o server
gcc  -lsrt test-c-server.c -o server


测试：

./test-c-server 127.0.0.1 10086
./test-c-client 127.0.0.1 10086

docs/api.md要仔细看
srt.h中的接口文件
如果只想看cpp里的注释

grep -nR "//" `find . -name *.cpp`  >zhushi.txt