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);
...
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
Thank you very much
Andr?
