[Kamailio-Users] remove codec from SDP

Ovidiu Sas osas at voipembedded.com
Tue Mar 31 17:23:52 CEST 2009


On Tue, Mar 31, 2009 at 10:43 AM, Iñaki Baz Castillo <ibc at aliax.net> wrote:
> 2009/3/31 Ovidiu Sas <osas at voipembedded.com>:
>> Hello Klaus,
>>
>> No, there isn't.  But it shouldn't be that hard to add one using the
>> sdp parser from the core.
>> Once the sdp is parsed, the lumps must be added (the relevant pointers
>> to the codecs and attributes are already saved in the parsed sdp
>> structure).
>
> Note that the only line to be modified is the "m=..." line, which
> specifies which codes are offered.
>
> Example:
>
> -------------------------------
> v=0
> o=root 3836 3836 IN IP4 222.220.19.45
> s=session
> c=IN IP4 222.220.19.45
> b=CT:384
> t=0 0
> m=audio 12342 RTP/AVP 18 0 8 3 101
> a=rtpmap:18 G729/8000
> a=fmtp:18 annexb=no
> a=rtpmap:0 PCMU/8000
> a=rtpmap:8 PCMA/8000
> a=rtpmap:3 GSM/8000
> a=rtpmap:101 telephone-event/8000
> a=fmtp:101 0-16
> a=silenceSupp:off - - - -
> a=ptime:20
> a=sendrecv
> m=video 10482 RTP/AVP 34 103 99
> a=rtpmap:34 H263/90000
> a=rtpmap:103 h263-1998/90000
> a=rtpmap:99 H264/90000
> a=sendrecv
> -------------------------------
>
> To dissable GSM in the above SDP the only modification would be:
>
>  m=audio 12342 RTP/AVP 18 0 8 101

That will work, but the proper thing to do would be to also remove the
'a=rtpmap:3 GSM/8000' line.

Regards,
Ovidiu Sas




More information about the sr-users mailing list