I needed an "inherit_codec = true" before the bridge for this to work. For some reason, setting ringback also trips this up in some cases, but it's been a while since I looked at this so YMMV.

On Mon, 20 Sept 2021 at 18:02, Shahnawaj Khan <shahnawaj.khan1990@gmail.com> wrote:

Hi All,

I am working on a use case where we don't want freeswitch to transcode
and the codec negotiated with the B leg's answer should be passed to
the A leg so it also uses the same codec.
I have followed the following link
https://freeswitch.org/confluence/display/FREESWITCH/Codec+Negotiation
and added following flags in sip profiles
<param name="inbound-late-negotiation" value="true"/>
<param name="inherit_codec" value="true"/>
But freeswitch is itself doing the transcoding. Scenario looks like
the following.

1) Bob---(Invite with OPUS,PCMU codec)---->Freeswitch
2) Freeswitch---(Invite with OPUS,PCMU codec)-->Alice
3) Alice ---(200 OK with PCMU)---> Freeswitch
4) Freeswitch---(200 OK with OPUS)--->Bob //OPUS instead of PCMU

Please let me know if I have some understanding gaps and point me in
the right direction.

Thanks & Regards,
Shahnawaz