[FFmpeg-trac] #9294(avformat:new): Multi-client SRT server

[FFmpeg]

#9294: Multi-client SRT server
-------------------------------------+-------------------------------------
             Reporter:  a_sheetov    |                     Type:
                                     |  enhancement
               Status:  new          |                 Priority:  normal
            Component:  avformat     |                  Version:  git-
             Keywords:  libsrt srt   |  master
  multi-client                       |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 I’m using ffmpeg as a library from within my app. I’m currently developing
 an SRT server that accepts client connections and streams video to them. I
 compiled ffmpeg with libsrt and implemented SRT server based on a standard
 muxer (options: mode=listener, transtype=live).

 During testing, I found two problems:
 1. Data transfer doesn’t start until the first client connects
 2. The second client can’t connect after the first one

 So it looks like ffmpeg implementation of SRT server does not support
 multiple concurrent client connections.

 I looked at the source code (libavformat/libsrt.c) and my assumptions were
 confirmed:

 {{{
 static int libsrt_listen(int eid, int fd, const struct sockaddr *addr,
 socklen_t addrlen, URLContext *h, int64_t timeout)
 {
     int ret;
     int reuse = 1;
     if (srt_setsockopt(fd, SOL_SOCKET, SRTO_REUSEADDR, &reuse,
 sizeof(reuse))) {
         av_log(h, AV_LOG_WARNING, "setsockopt(SRTO_REUSEADDR) failed\n");
     }
     if (srt_bind(fd, addr, addrlen))
         return libsrt_neterrno(h);

     if (srt_listen(fd, 1))
         return libsrt_neterrno(h);

     ret = libsrt_network_wait_fd_timeout(h, eid, 1, timeout,
 &h->interrupt_callback);
     if (ret < 0)
         return ret;

     ret = srt_accept(fd, NULL, NULL);
     if (ret < 0)
         return libsrt_neterrno(h);
     if (libsrt_socket_nonblock(ret, 1) < 0)
         av_log(h, AV_LOG_DEBUG, "libsrt_socket_nonblock failed\n");

     return ret;
 }

 static int libsrt_setup(URLContext *h, const char *uri, int flags)
 {
     // ...
     if (s->mode == SRT_MODE_LISTENER) {
         // multi-client
         ret = libsrt_listen(write_eid, fd, cur_ai->ai_addr,
 cur_ai->ai_addrlen, h, s->listen_timeout);
         srt_epoll_release(write_eid);
         if (ret < 0)
             goto fail1;
         srt_close(fd);
         fd = ret;
     }
     // ...
 }
 }}}

 After the first client connects, server socket is closed and its
 descriptor is replaced with the client socket descriptor.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9294>
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