[asterisk-users] g729a compatibility

[Elliot Murdock]

Hello!

I noticed that the SIP packet contains this line:

m=audio 60000 RTP/AVP 18 98 96 97 101 13

However, there is no rtpmap that describes 18.  Media format 18
Apparently refers to G729, but there is no rtpmap in the SDP for it.
Since G729 is a registered and known format is there any way for
Asterisk to negotiate it within an explicit rtpmap?

Thank you,
Elliot

On Thu, Jul 2, 2009 at 9:34 AM, Elliot Murdock<murdocke at gmail.com> wrote:
> Hello!
>
> Thank you for that piece of information.  Which RFC does it state that
> the audio name is "G729"?
>
> Thanks,
> Elliot
>
> On Thu, Jul 2, 2009 at 12:16 AM, Kevin P. Fleming<kpfleming at digium.com> wrote:
>> Elliot Murdock wrote:
>>> Hello!
>>>
>>> I have a sip device that is sending in the SDP:
>>>
>>> rtpmap:98 g729a
>>>
>>> It does not seem like Asterisk is negotiating the codec properly,
>>> because while the call rings, the rtp lines fail.  However, on other
>>> sip devices that have "rtpmap:18 g729" in their SDP, things work fine
>>> with Digium's commercial g729 license.
>>>
>>> How do I get "98 g729a" recognized by Asterisk?
>>
>> You don't. That's not a standards-compliant way of reporting G.729A in
>> SDP. The RFC says it should be 'G729', but Asterisk also accepts 'G.729'
>> and 'G729A'. It does not accept any lowercase form of the codec name.
>>
>> --
>> Kevin P. Fleming
>> Digium, Inc. | Director of Software Technologies
>> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
>> skype: kpfleming | jabber: kpfleming at digium.com
>> Check us out at www.digium.com & www.asterisk.org
>>
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>