[FFmpeg-user] stream RTP over UDP from specific source to destination (negotiated using SIP SDP) using ffmpeg

[prashantha S]

Hi,

I am trying to stream RTP over UDP from specific source to destination
(negotiated using SIP SDP) using ffmpeg
I would like to open the source port and send the packets to destination
port from this port

This is because
1. my destination will always check from where the RTP is coming from
(source verification)
2. Another usage by opening the source port is - receive packets sent from
destination, otherwise destination will complain "ICMP unreachable"
SIP session INVITE source SDP

c=IN IP4 172.27.6.45
t=0 0
m=video 20002 RTP/AVP 120
b=AS:768
a=rtpmap:120 VP8/90000
a=sendrecv


SIP session INVITE destination SDP

m=video 40154 RTP/AVP 120
c=IN IP4 10.211.5.13
b=AS:768
a=rtpmap:120 VP8/90000
a=sendrecv


So i have tried the below in source
ffmpeg -re -i HD.webm -t 00:01:00 -an -vcodec libvpx -s 352x288 -b:v 768k
-r 30 -f rtp rtp://10.211.5.13:40154?localaddr=172.27.6.45&localport=20002

But using ffmpeg i am not able to achieve this
1. FFMPEG does not stream from source IP&port i.e.
localaddr=172.27.6.45&localport=20002. It uses random ports
    Does the usage of "?localaddr=172.27.6.45&localport=20002" is correct?
2. Destination complain that "ICMP unreachable" for 172.27.6.45:20002

Is there any solution for these 2 issues?

Thank you
Psaya