How to force RTP “Payload type” to AMR ?

Hi

I have a application for monitoring the network. This application has a button to start Wireshark to display the captured traffic.

Sometime the RTP payload type is well recognized (AMR-WB) by Wireshark and I can use use the use "RTP -> Stream Analysis".

Sometime it's "Unknown" and I can't use the Stream Analysis (the graph is empty). I changed the Preferences->Protocol->AMR->AMR Dynamic Payload Type, this add a new tree "AMR-WB" in the protocol layers, but the RTP payload type remains "Unknown" and I still can't use the Stream Analysis.

Also if I save the pcap (the one with RTP type well recognized AMR-WB) and open it again, Wireshark loses the information and display "DynamicRTP", so I can't use the Stream Analysis anymore.

That means our monitoring application, when launching Wireshark, probably loads a profil to set the RTP payload type to AMR-WB. Is it possible to do that with Wireshark ?

How can I force the RTP Payload Type to AMR ?

See attachement. It's exactly the same flow (but monitored at 2 different places).

Thank you!!

rtp amr

rtp not recognized