diff --git a/trunk/3rdparty/st-srs/Makefile b/trunk/3rdparty/st-srs/Makefile
index 7e641d195..7102eedb4 100644
--- a/trunk/3rdparty/st-srs/Makefile
+++ b/trunk/3rdparty/st-srs/Makefile
@@ -189,10 +189,6 @@ OTHER_FLAGS = -Wall
 ifeq ($(shell test -f /usr/include/sys/epoll.h && echo yes), yes)
 DEFINES     += -DMD_HAVE_EPOLL
 endif
-# For SRS, sendmmsg
-ifeq ($(shell grep -qs sendmmsg /usr/include/sys/socket.h && echo yes), yes)
-DEFINES     += -DMD_HAVE_SENDMMSG -D_GNU_SOURCE
-endif
 endif
 
 ifeq ($(OS), NETBSD)
diff --git a/trunk/3rdparty/st-srs/io.c b/trunk/3rdparty/st-srs/io.c
index 750099450..7e05f99ae 100644
--- a/trunk/3rdparty/st-srs/io.c
+++ b/trunk/3rdparty/st-srs/io.c
@@ -742,17 +742,16 @@ int st_sendmsg(_st_netfd_t *fd, const struct msghdr *msg, int flags, st_utime_t
     return n;
 }
 
-
-#if defined(MD_HAVE_SENDMMSG) && defined(_GNU_SOURCE)
-int st_sendmmsg(st_netfd_t fd, struct mmsghdr *msgvec, unsigned int vlen, int flags, st_utime_t timeout)
+int st_sendmmsg(st_netfd_t fd, struct st_mmsghdr *msgvec, unsigned int vlen, int flags, st_utime_t timeout)
 {
+#if defined(MD_HAVE_SENDMMSG) && defined(_GNU_SOURCE)
     int n;
     int left;
     struct mmsghdr *p;
 
     left = (int)vlen;
     while (left > 0) {
-        p = msgvec + (vlen - left);
+        p = (struct mmsghdr*)msgvec + (vlen - left);
 
         if ((n = sendmmsg(fd->osfd, p, left, flags)) < 0) {
             if (errno == EINTR)
@@ -772,8 +771,30 @@ int st_sendmmsg(st_netfd_t fd, struct mmsghdr *msgvec, unsigned int vlen, int fl
         return n;
     }
     return (int)vlen - left;
-}
+#else
+    struct st_mmsghdr *p;
+    int i, n;
+
+    // @see http://man7.org/linux/man-pages/man2/sendmmsg.2.html
+    for (i = 0; i < (int)vlen; ++i) {
+        p = msgvec + i;
+        n = st_sendmsg(fd, &p->msg_hdr, flags, timeout);
+        if (n < 0) {
+            // An error is returned only if no datagrams could be sent.
+            if (i == 0) {
+                return n;
+            }
+            return i + 1;
+        }
+
+        p->msg_len = n;
+    }
+
+    // Returns the number of messages sent from msgvec; if this is less than vlen, the caller can retry with a
+    // further sendmmsg() call to send the remaining messages.
+    return vlen;
 #endif
+}
 
 
 /*
diff --git a/trunk/3rdparty/st-srs/public.h b/trunk/3rdparty/st-srs/public.h
index c54bd790a..80fd93346 100644
--- a/trunk/3rdparty/st-srs/public.h
+++ b/trunk/3rdparty/st-srs/public.h
@@ -151,7 +151,15 @@ extern int st_recvfrom(st_netfd_t fd, void *buf, int len, struct sockaddr *from,
 extern int st_sendto(st_netfd_t fd, const void *msg, int len, const struct sockaddr *to, int tolen, st_utime_t timeout);
 extern int st_recvmsg(st_netfd_t fd, struct msghdr *msg, int flags, st_utime_t timeout);
 extern int st_sendmsg(st_netfd_t fd, const struct msghdr *msg, int flags, st_utime_t timeout);
-extern int st_sendmmsg(st_netfd_t fd, struct mmsghdr *msgvec, unsigned int vlen, int flags, st_utime_t timeout);
+
+// @see http://man7.org/linux/man-pages/man2/sendmmsg.2.html
+#include <sys/socket.h>
+struct st_mmsghdr {
+   struct msghdr msg_hdr;  /* Message header */
+   unsigned int  msg_len;  /* Number of bytes transmitted */
+};
+extern int st_sendmmsg(st_netfd_t fd, struct st_mmsghdr *msgvec, unsigned int vlen, int flags, st_utime_t timeout);
+
 extern st_netfd_t st_open(const char *path, int oflags, mode_t mode);
 
 #ifdef DEBUG