And no, the codec has to be agreed to between the endpoints. What you are suggesting is something called "transcoding", which is hugely processor intensvive. Not many things out there "transcode", for a reason.
When an invite happens, another part is an "offer" of codecs, the other side has to look at what's offered and agree to the offer based on its available list. There is a preference order on both sides. This includes the caller, the callee, and any transferred destination (like voicemal). ============================ Tony Graziano, Manager Telephone: 434.984.8430 Fax: 434.984.8431 Email: [email protected] LAN/Telephony/Security and Control Systems Helpdesk: Telephone: 434.984.8426 Fax: 434.984.8427 Helpdesk Contract Customers: http://www.myitdepartment.net/gethelp/ ----- Original Message ----- From: [email protected] <[email protected]> To: sipx-users <[email protected]> Sent: Mon Nov 02 20:06:15 2009 Subject: Re: [sipx-users] codecs supported? On Mon, 2 Nov 2009 19:56:26 -0500 (EST), Francis Tinio wrote: > Doesn't g729 use less bandwidth than g711? So it should have better > performance and resource management. Yes, it's somewhere around the 8k mark, give or take headroom. But this got me thinking... So, my SIP gateway has g729 available, but how does it come into play? So, user1 makes a call using one of the PRI trunks so goes through the gateway. The gateway tries to establish the connection using the best codec it can. Sipx has nothing what so ever to say in the matter right? Since the end points are basically just being connected together, it's the phones and what ever is in between that set the codec no? So, user1 calls someone who has a phone which can do g729, the call is done using g729. Or, user1 calls someone who's phone can't do g729 so the parties are connected together at say g711. Now, what if user1's phone isn't g729 aware but the gateway and the called party is too. Does that mean g711 from user1 to gateway and g711 to the called party since they aren't using one of the PRIs? _______________________________________________ sipx-users mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-users Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-users sipXecs IP PBX -- http://www.sipfoundry.org/ _______________________________________________ sipx-users mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-users Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-users sipXecs IP PBX -- http://www.sipfoundry.org/
