[Users] rtp relay & transcoding

Regarding RTP relay (e.g. media proxy), and transcoding -- This topic has come up many times before in various forms, but I still have not found any obvious solution that's highly scalable and cheap (well sure, I can dream). We have lots of customers behind various firewalls using various codecs. Customers call each other (both parties behind firewall) and to/from carriers. Certainly this is a common use-case. What do you do? What are best known practices? Commercial media gateway, or open-source solutions? We use both OpenSER and a custom B2BUA written against the NIST Java stack. We need a way to transcode when needed. Obviosly mediaproxy module is great, but doesn't transcode. Ideally, what I'm looking for: * at the point where our system determines that transcoding or rtp relay is needed, a media gateway is chosen based on network proximity (e.g.: 1/2 our customers are in the U.S., 1/2 in Brazil; should pick a media gateway accordingly to minimize network path). * our system then signals the media gateway (mgcp?) to setup the channels, and modifies the SDPs in the SIP path accordingly. * even more ideally: the media gateway signals our system with inband or rfc2833 dtmf events, plus rtcp reports when available. I think Asterisk could be hacked to do this. Does anyone know of a commercial product that's not too expensive? Thoughts? Advice? thanks, -- Ryan Mitchell <rjm(a)tcl.net> Telecom Logic, LLC http://www.tcl.net