Benny Prijono wrote: >> Yes, I'm really sure that the only thing to do is to intercept the >> incoming RTP traffic. I have discoverd it using xten-xlite, I have made >> a lot of tries with tcpdump & ngrep, when I make a call to an external >> phone I have saw that: >> - the SIP packet 180 ringing doesn't arrive, never >> - I receive a SIP packet: 183 Session Progress >> - xten-xlite doesn't play the local ringing tone until the change of RTP >> traffic >> >> I really made many tries and I'm sure that the only SIP packet that >> arrive when the call in on going is 183 Session Progress and "viewing" >> with ngrep the RTP packets is really clear that, at a moment when the >> traffic change, the client start to play the local ringing tone that >> simulate the remote ringing. This moment is exactly when the remote >> phone is really ringing. So I'm sure at 100% that I have to get the RTP >> traffic. >> I don't already know what changes of the traffic I have to intercept but >> first of all I have to get it. >> > > Sorry now I'm a bit lost. If you said you've got 183, then why can't > you just "start the call" with the arrival of this 183 response > (rather than waiting for the 180 response). It is quite common to > receive 183 instead of 180 if you are calling a PSTN gateway, and if > you listen to the incoming audio most likely you will hear ringing > tone with the 183 response. Yes, I have to call mobile phones. > Since you've had 183 (and I assume there is SDP in the 183), your > media has been established, and your on_call_media_state() callback > should have been called. Yes, you right, in the 183 there is SDP, the media is established and the on_call_media_state is called. > So now you can just poll the media statistic of the call to see if > you've received RTP packets. You can use "dq" command in pjsua to show > the call's media statistic (and trace the implementation of this > command to see how to retrieve the media statistic programmatically). I have tried to do that, I saw that the "dq" calls the pjsua_call_dump and I saw in the implementation that it calls dump_media_session to retrive RTP statistic. The the problem is: how can I understand from the statistics when the remote phone is ringing ? I have to know exactly when the remote phone start to ring and I have to immediatly hang up the call. The program that I'm writing must do only a single ring on the remote phone, this is a kind of "cover signal" that wakeup the mobile phone. The program need to be perfectly synchronized because I have to minimize the ringing time so the user cannot answer to the call. If the user answer to the call I have a to pay for it, so the ringing time must be really short to avoid charge for me. cheers Davide
