[Spce-user] Command “RTP” converts SAVPF to AVP — F is missing in the destination

[Richard Fuchs]

That's not really how it works though. As soon as one of these protocol 
options is given, the protocol is selected from the options given. The 
original protocol is not taken into account. So with only "RTP" given, 
that comes out as RTP/AVP, because AVP is the default is AVPF is not.

Cheers


On 08/04/2023 11.30, Дилян Палаузов via Spce-user wrote:
> Hello,
>
> kamailio/rtpengine receives SDP containing:
>
> m=audio 28782 UDP/TLS/RTP/SAVPF 111 63 9 0 8 13 110 126
>
> In order to remove the security, I call in Kamailio
>
> KSR.rtpengine.rtpengine_manage("replace-session-connection replace-origin SDES-pad SIP-source-address RTP")
>
> The outgoing SDP contains:
>
> m=audio 39954 RTP/AVP 111 63 9 0 8 13 110 126
>
>
> Considering that the code says nothing about AVP my expectation is that SAVPF is converted to AVPF and the system sends RTP/AVPF.  That is, I expect
> as output
>
> m=audio 39954 RTP/AVPF 111 63 9 0 8 13 110 126
>
> My expectation is based also on my reading of https://kamailio.org/docs/modules/devel/modules/rtpengine.html :
>
>> RTP, SRTP, DTLS, AVP, AVPF - These flags control the RTP transport protocol that should be used towards the recipient of the SDP. If none of them
> are specified, the protocol given in the SDP is left untouched. Otherwise, the “SRTP” flag indicates that SRTP should be used, while “RTP” indicates
> that SRTP should not be used. “AVPF” indicates that the advanced RTCP profile with feedback messages should be used, and “AVP” indicates that the
> regular RTCP profile should be used. See also the next set of flags below.
>
> “should be used” does not mean that any rewritings will be done.
>
> I use nearly the lastest version of rtpengine on git.
>
> I want only to strip the encryption, in order to do test calls to http://enum-test.at/index.html ⇔ sip.nemox.net, keeping the “feedback” if it was
> present.  The latter does not support encryption.
>
> Greetings
>    Дилян
>