Getting "Media Format = 0"

Discussion:

Nitin Kapoor

2010-03-12 14:06:57 UTC

Hello Friends,

I am facing the problem with one of my client. I can see we are getting the
2 codecs in SDP(G.711 & G.729) with payload "0, 101, 19".

Now here is my doubt is that whenver my client is sending the SDP in initial
OFFER with G.729 its offering "Media format = 0".But when i checked the RFC
3264 and others, then i observed that it can be possible if you have two
codecs in one SDP then one media format can be "0".

Below is the OFFERED SDP from my SOURCE UA.

Media Description, name and address (m): audio 17890 RTP/AVP 0 101 19
Media Type: audio
Media Port: 17890
Media Protocol: RTP/AVP
Media Format: ITU-T G.711 PCMU
Media Format: DynamicRTP-Type-101
Media Format: Comfort noise (old)

Connection Information (c): IN IP4 212.48.160.163
Connection Network Type: IN
Connection Address Type: IP4
Connection Address: 212.48.160.163

Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute Fieldname: rtpmap
Media Format: 0
MIME Type: PCMU
Sample Rate: 8000

Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute Fieldname: rtpmap
Media Format: 101
MIME Type: telephone-event
Sample Rate: 8000

Media Attribute (a): fmtp:101 0-16
Media Attribute Fieldname: fmtp
Media Format: 101 [telephone-event]
Media format specific parameters: 0-16
Media Attribute (a): rtpmap:19 CN/8000
Media Attribute Fieldname: rtpmap
Media Format: 19
MIME Type: CN
Sample Rate: 8000

Media Attribute (a): ptime:20
Media Attribute Fieldname: ptime
Media Attribute Value: 20

Here is SDP is offered by my Remote Entity in 183 Session progress in the
correspondence of of INITIAL INVITE.

Media Description, name and address (m): audio 5870 RTP/AVP 0 101
Media Type: audio
Media Port: 5870
Media Protocol: RTP/AVP
Media Format: ITU-T G.711 PCMU
Media Format: DynamicRTP-Type-101
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute Fieldname: rtpmap
Media Format: 0
MIME Type: PCMU
Sample Rate: 8000
Media Attribute (a): sendrecv
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute Fieldname: rtpmap
Media Format: 101
MIME Type: telephone-event
Sample Rate: 8000

Now the problem which i am facing is that after doing the Negotiation and
the ACK of 200 OK in the correspondence in INITIAL OFFER/INVITE, i am
getting a BYE immediately from my source UA.

Could anyone please help me to diagnose this.

Thanks,
Nitin kapoor

Nitin Kapoor

2010-03-12 18:57:00 UTC

Permalink

Hello,

Can anyone please help me out on the below issue.

Thanks,
Nitin Kapoor

Post by Nitin Kapoor
Hello Friends,
I am facing the problem with one of my client. I can see we are getting the
2 codecs in SDP(G.711 & G.729) with payload "0, 101, 19".
Now here is my doubt is that whenver my client is sending the SDP in
initial OFFER with G.729 its offering "Media format = 0".But when i checked
the RFC 3264 and others, then i observed that it can be possible if you have
two codecs in one SDP then one media format can be "0".
Below is the OFFERED SDP from my SOURCE UA.
Media Description, name and address (m): audio 17890 RTP/AVP 0 101 19
Media Type: audio
Media Port: 17890
Media Protocol: RTP/AVP
Media Format: ITU-T G.711 PCMU
Media Format: DynamicRTP-Type-101
Media Format: Comfort noise (old)
Connection Information (c): IN IP4 212.48.160.163
Connection Network Type: IN
Connection Address Type: IP4
Connection Address: 212.48.160.163
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute Fieldname: rtpmap
Media Format: 0
MIME Type: PCMU
Sample Rate: 8000
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute Fieldname: rtpmap
Media Format: 101
MIME Type: telephone-event
Sample Rate: 8000
Media Attribute (a): fmtp:101 0-16
Media Attribute Fieldname: fmtp
Media Format: 101 [telephone-event]
Media format specific parameters: 0-16
Media Attribute (a): rtpmap:19 CN/8000
Media Attribute Fieldname: rtpmap
Media Format: 19
MIME Type: CN
Sample Rate: 8000
Media Attribute (a): ptime:20
Media Attribute Fieldname: ptime
Media Attribute Value: 20
Here is SDP is offered by my Remote Entity in 183 Session progress in the
correspondence of of INITIAL INVITE.
Media Description, name and address (m): audio 5870 RTP/AVP 0 101
Media Type: audio
Media Port: 5870
Media Protocol: RTP/AVP
Media Format: ITU-T G.711 PCMU
Media Format: DynamicRTP-Type-101
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute Fieldname: rtpmap
Media Format: 0
MIME Type: PCMU
Sample Rate: 8000
Media Attribute (a): sendrecv
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute Fieldname: rtpmap
Media Format: 101
MIME Type: telephone-event
Sample Rate: 8000
Now the problem which i am facing is that after doing the Negotiation and
the ACK of 200 OK in the correspondence in INITIAL OFFER/INVITE, i am
getting a BYE immediately from my source UA.
Could anyone please help me to diagnose this.
Thanks,
Nitin kapoor

Vijay Tiwari

2010-03-13 16:27:15 UTC

Permalink

Hello Nitin

If you are talking about codec payload then

" I can see we are getting the 2 codecs in SDP(G.711 & G.729) with payload
"0, 101, 19". "

in this payload there is no G.729 because for G.729 payload is 18.

thanks
vijay

--
They can because they think they can.

Nitin Kapoor

2010-03-13 16:33:06 UTC

Permalink

Yes.. i agree with you.. i haven't seen payload 18 on any SDP( niether from
source nor from remote).

Now here is my doubt about media format...is the correct to leave it "0"

Thanks,
Nitin Kapoor

Post by Vijay Tiwari
Hello Nitin
If you are talking about codec payload then
" I can see we are getting the 2 codecs in SDP(G.711 & G.729) with payload
"0, 101, 19". "
in this payload there is no G.729 because for G.729 payload is 18.
thanks
vijay

Post by Nitin Kapoor
Hello Friends,
I am facing the problem with one of my client. I can see we are getting
the 2 codecs in SDP(G.711 & G.729) with payload "0, 101, 19".
Now here is my doubt is that whenver my client is sending the SDP in
initial OFFER with G.729 its offering "Media format = 0".But when i checked
the RFC 3264 and others, then i observed that it can be possible if you have
two codecs in one SDP then one media format can be "0".
Below is the OFFERED SDP from my SOURCE UA.
Media Description, name and address (m): audio 17890 RTP/AVP 0 101 19
Media Type: audio
Media Port: 17890
Media Protocol: RTP/AVP
Media Format: ITU-T G.711 PCMU
Media Format: DynamicRTP-Type-101
Media Format: Comfort noise (old)
Connection Information (c): IN IP4 212.48.160.163
Connection Network Type: IN
Connection Address Type: IP4
Connection Address: 212.48.160.163
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute Fieldname: rtpmap
Media Format: 0
MIME Type: PCMU
Sample Rate: 8000
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute Fieldname: rtpmap
Media Format: 101
MIME Type: telephone-event
Sample Rate: 8000
Media Attribute (a): fmtp:101 0-16
Media Attribute Fieldname: fmtp
Media Format: 101 [telephone-event]
Media format specific parameters: 0-16
Media Attribute (a): rtpmap:19 CN/8000
Media Attribute Fieldname: rtpmap
Media Format: 19
MIME Type: CN
Sample Rate: 8000
Media Attribute (a): ptime:20
Media Attribute Fieldname: ptime
Media Attribute Value: 20
Here is SDP is offered by my Remote Entity in 183 Session progress in the
correspondence of of INITIAL INVITE.
Media Description, name and address (m): audio 5870 RTP/AVP 0 101
Media Type: audio
Media Port: 5870
Media Protocol: RTP/AVP
Media Format: ITU-T G.711 PCMU
Media Format: DynamicRTP-Type-101
Media Attribute (a): rtpmap:0 PCMU/8000
Media Attribute Fieldname: rtpmap
Media Format: 0
MIME Type: PCMU
Sample Rate: 8000
Media Attribute (a): sendrecv
Media Attribute (a): rtpmap:101 telephone-event/8000
Media Attribute Fieldname: rtpmap
Media Format: 101
MIME Type: telephone-event
Sample Rate: 8000
Now the problem which i am facing is that after doing the Negotiation and
the ACK of 200 OK in the correspondence in INITIAL OFFER/INVITE, i am
getting a BYE immediately from my source UA.
Could anyone please help me to diagnose this.
Thanks,
Nitin kapoor
_______________________________________________
Sip mailing list https://www.ietf.org/mailman/listinfo/sip
This list is essentially closed and only used for finishing old business.
SIP implementation.
specifications.

--
They can because they think they can.