unable to see codecs used in VOIP application using Wireshark

Question

Is there any way to see the codecs used in VOIP application in wireshark(G729,AMR…).

I want to analyse a VOIP appliocation ,in which i can see SIP methods only.I didn't find a way to see any codecs used.Also i tried to see RTP packets,which i couldn't find(i searched for rtp for filtering)find.I actuallally made a call from VOIP application and was only able to see SIP protocol.Do anyone have any idea to analyse SRTP on wireshark.I am using MAC system.I couldn't find RTP for the same call.Can anyone help?

Answer 1

If channel encrypted using SRTP so you can not analysis the packet to know the format of it. If you want to know which codec in use better catch SIP messages from call beginning, but if signal SIP go on SSL/TLS channel so it can not read too.