G.729 codec is being removed from the answer SDP

[Rahul Dhuri]

Hi,

Looking for some suggestion on the scenario below and see what our options are.

We see RtpEngine deletes the G729 codec from the 'answer' when there is a mismatch in the 'annexb' attribute of G729.  The original Invite was with annexb=yes attribute, and the 183 response from B party is coming back with annexb=no attribute. 

I see below message in RTPEngine logs, which looks like this is done on purpose.

[1770617053.569755] DEBUG: [159450353296313653]: [codec] Not adding stray answer codec G729/8000/annexb=no (18)

Is there a way so that RTPengine does not delete the G729 codec in this case ?

RtpEngine response of command 'offer':

====================

t=0 0

m=audio 44234 RTP/AVP 18 8 0 96

a=maxptime:40

a=rtpmap:18 G729/8000

a=fmtp:18 annexb=yes

a=rtpmap:8 PCMA/8000

a=rtpmap:0 PCMU/8000

a=rtpmap:96 telephone-event/8000

a=fmtp:96 0-15

a=sendrecv

a=rtcp:44235

183 response from B-party:

====================

t=0 0

m=audio 15036 RTP/AVP 18 96

a=rtpmap:18 G729/8000

a=fmtp:18 annexb=no

a=rtpmap:96 telephone-event/8000

a=fmtp:96 0-15

a=sendrecv

a=maxptime:20

RtpEngine response of command 'answer':

==================================

c=IN IP4 172.28.0.5

t=0 0

m=audio 30266 RTP/AVP 96

a=maxptime:20

a=rtpmap:96 telephone-event/8000

a=fmtp:96 0-15

a=sendrecv

a=rtcp:30267

Thanks,

Rahul

[Richard Fuchs]

What version are you on? I believe this was fixed at some point, see commit 79983090.

Cheers

--
You received this message because you are subscribed to the Google Groups "Sipwise rtpengine" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rtpengine+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rtpengine/f18fc542-471f-4314-8783-2e02edd30afen%40googlegroups.com.

[Orgad Shaneh]

We noticed this bug too. It broke between 13.4.1.2 and 13.5.1.1, and the only commit that looks suspicious is 79983090, so I suppose it actually broke at least our use-case.

Offer:
v=0
o=AudiocodesGW 527643834 1857182468 IN IP4 10.1.2.3
s=SBC-Call
c=IN IP4 10.1.2.3
t=0 0
m=audio 21908 RTP/AVP 18 101
c=IN IP4 10.1.2.3
a=ptime:20
a=sendonly
a=label:1

a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no

a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15,16
m=audio 21912 RTP/AVP 18 101
c=IN IP4 10.1.2.3
a=ptime:20
a=sendonly
a=label:2

a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no

a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15,16

Answer from 13.4.1.2:
v=0
o=AudiocodesGW 923803701 830834448 IN IP4 10.1.2.4
s=SBC-Call
t=0 0
m=audio 51806 RTP/AVP 18 101
c=IN IP4 10.1.2.4
a=rtpmap:18 G729/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:18 annexb=no
a=fmtp:101 0-15,16
a=rtcp:51807
a=ptime:20
a=recvonly
a=label:1
m=audio 43144 RTP/AVP 18 101
c=IN IP4 10.1.2.4
a=rtpmap:18 G729/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:18 annexb=no
a=fmtp:101 0-15,16
a=rtcp:43145
a=ptime:20
a=recvonly
a=label:2

Answer from 13.5.1.1:
v=0
o=AudiocodesGW 527643834 1857182468 IN IP4 10.1.2.5
s=rtpengine-13-5-1-3-0-mr13-5-1-3-git-HEAD-63dd876
t=0 0
m=audio 40502 RTP/AVP 101
c=IN IP4 10.1.2.5
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15,16
a=recvonly
a=rtcp:40503
a=ptime:20
m=audio 50458 RTP/AVP 101
c=IN IP4 10.1.2.5
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15,16
a=recvonly
a=rtcp:50459
a=ptime:20

- Orgad

[Orgad Shaneh]

I take it back. The issue in our case is because we switched from offer/answer to publish, and we didn't install libbcg729 :/

Installed it now and it works fine.

See https://github.com/sipwise/rtpengine/pull/2071

[Rahul Dhuri]

Thanks Richard. 

We are on version 10.5.6, looks like we don't have the fix.

Regards,

Rahul