Overriding the on_rx_offer() callback, solved the problems ;-)
All I nedded to do was change the port from 'offer' and set it as the sdp to use on the answer
offer->media[0]->desc.port = <port>
pjsip_inv_set_sdp_answer(inv, offer);
All went Ok
Thanks
Andr?
Benny Prijono wrote:
> Hi Andr?,
>
> On 3/4/08, Andr? Teixeira <coelho at wit-software.com> wrote:
>
>> Hello, i'm new to pjsip and i am with a problem, i've searched for
>> examples, tried several things, but I was not able to solve it :(
>>
>> I'm trying to establish a T.38 fax session, and in order to do that it
>> is necessary to follow the following steps. Imagine A wants to send a
>> fax to B.
>>
>>
>> 1- A calls B,
>> 2- A sends a special tone to B
>> 3- B detects the tone
>> 4- B sends a reINVITE with it's fax capabilites:
>>
>> [...]
>> m=image <port> udptl t38
>> a=T38FaxVersion:0
>> a=T38MaxBitRate:14400
>> a=T38FaxMaxBuffer:200
>> a=T38FaxMaxDatagram:72
>> a=T38FaxUdpEC:t38UDPRedundancy
>> a=T38FaxRateManagement:transferredTCF
>>
>>
>> 5- A sends 200 OK with the following information in the SDP
>> [...]
>> m=image <port> udptl t38
>>
>>
>>
>> A B
>> Invite ->
>> <-200 OK
>> Special tone ->
>> <-INVITE
>> 200 ok ->
>>
>>
>> I think i can try two different approaches, but i'm not being able to
>> test neither successfully.
>>
>> 1- change the SDP from the dialog so all my following answers after my
>> initial Invite contain a SDP with m=image <port> udptl t38. Trying to
>> do that I always get an error of something related to "OFFER"
>>
>> ...
>> pj_strdup(pool_vars, &m_video->desc.media, &pj_str("image"));
>> m_video->desc.port = port;
>> m_video->desc.port_count = 1;
>> pj_strdup (pool_vars, &m_video->desc.transport, &pj_str("udptl"));
>>
>> m_video->desc.fmt_count = 1;
>> m_video->desc.fmt[0] = pj_str("t38");
>>
>> pjsip_inv_set_sdp_answer(this->g_inv, local_sdp);
>> ...
>>
>>
>
> What's the exact error code/message that you see?
>
>
>
>> 2- intercept the reInvite and respond with the correct SDP, I am able to
>> catch the INVITE from B, by listening all dialog request, BUT I have
>> never managed to send an answer :(
>>
>> Does anyone have any ideia how can I respond to an INVITE received
>> inside a dialog and how can I set the SDP to contain m=image <port>
>> udptl t38
>>
>>
>
> Rather than trapping all dialog events, the proper way to handle this
> is to override the on_rx_offer() callback of the invite session. This
> callback is called whenever the invite session receives new offer from
> remote, either in re-INVITE, UPDATE, or other means.
>
> Please see the comment/doxygen documentation of this callback for more
> information.
>
> cheers,
> -benny
>
>
>
>
>> Thank you very much
>>
>> Andr?
>>
>
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