Nnginx RTMP publish from Envivio - Strace

{{EPOLLIN, {u32=36974464, u64=36974464}}}, 512, 4294967295) = 1

accept4(11, {sa_family=AF_INET, sin_port=htons(37878), sin_addr=inet_addr("5.6.7.8")}, [16], SOCK_NONBLOCK) = 13

recvfrom(13, 0x2333d60, 1537, 0, 0, 0)  = -1 EAGAIN (Resource temporarily unavailable)

epoll_ctl(4, EPOLL_CTL_ADD, 13, {EPOLLIN|EPOLLET|0x2000, {u32=36974656, u64=36974656}}) = 0

epoll_wait(4, {{EPOLLIN, {u32=36974656, u64=36974656}}}, 512, 60000) = 1

recvfrom(13, "\3\3$\314\v\0\0\0\0\10\0\251\0>\0W\0\304\0\225\0\32\0\343\0\300\0\301\0006\0\257"..., 1537, 0, NULL, NULL) = 1537

epoll_ctl(4, EPOLL_CTL_DEL, 13, {0, {u32=0, u64=0}}) = 0

sendto(13, "\3\3$\314\v\0\0\0\0\10\0\251\0>\0W\0\304\0\225\0\32\0\343\0\300\0\301\0006\0\257"..., 1537, 0, NULL, 0) = 1537

sendto(13, "\3$\314\v\0\0\0\0\10\0\251\0>\0W\0\304\0\225\0\32\0\343\0\300\0\301\0006\0\257\0"..., 1536, 0, NULL, 0) = 1536

recvfrom(13, 0x2333d61, 1536, 0, 0, 0)  = -1 EAGAIN (Resource temporarily unavailable)

epoll_ctl(4, EPOLL_CTL_ADD, 13, {EPOLLIN|EPOLLET|0x2000, {u32=36974656, u64=36974656}}) = 0

epoll_wait(4, {{EPOLLIN, {u32=36974656, u64=36974656}}}, 512, 60000) = 1

recvfrom(13, "\3$\314\v\0\0\0\0\10\0\251\0>\0W\0\304\0\225\0\32\0\343\0\300\0\301\0006\0\257\0"..., 1536, 0, NULL, NULL) = 1536

epoll_ctl(4, EPOLL_CTL_DEL, 13, {0, {u32=0, u64=0}}) = 0

---- This is where the main differences start ----

recvfrom(13, "\3\0\0\0\0\0\330\24\0\0\0\0\2\0\7connect\0?\360\0\0\0\0\0\0\3"..., 146, 0, NULL, NULL) = 146

recvfrom(13, "\0\6swfUrl\2\0\34rtmp://1.2.3.4"..., 140, 0, NULL, NULL) = 83

close(13)                               = 0

epoll_wait(4,