[sorry if you receive this mail multiple times on multiple mailing list - I thought people on (open)serdev might be interested, but not necessarily subscribed to rtpproxy lists]
Hello, some time back Atle and me did a small hack to rtpproxy and nathelper so it could use the codecs from SEMS[1] to transcode RTP from one codec into another in the rtpproxy. Unfortunately we never had or spent the time to get this further than proof-of-concept. That is, iirc the rtpproxy part is quite ok, but the nathelper patch could need some eyes over it. As recently someone asked again about it, we thought we would just release the code as it is, so if there is anyone interested she or he could take the code, maybe improve and update it a little and maybe add it into rtpproxy/nathelper. It works the following way: - nathelper gets another function force_rtp_transcode, that takes the codec to encode to, and creates a completely new SDP with the local port and new codec line - nathelper tells rtpproxy to transcode with a new command option (T) that takes new codec id and format parameters - rtpproxy gets a new codec module path option, from where codec plugins are loaded - when rtpproxy is invoked with 'T' command option, it instantiates a rtpproxy transcoder session with two codec instances from the correct codec plugins - if a packet is received for an rtpproxy session with transcoder, it passes the packet through the codecs before sending The patch is against rtpproxy head from 14092006; since then I think the rtpproxy code has been a little restructured, so it would need some rework to go with current rtpproxy. It contains gsm, ilbc, speex-nb and g711 codec plugins; since then g726, l16, g722 (nb de/encoding) have been added to SEMS (though the codec interface has slightly changed, mostly optional stuff). Other codec wrappers (e.g. 729) could be added easily. A sample transcoder.cfg is in nathelper dir. The patch and files are available at http://user.cs.tu-berlin.de/~sayer/transcoder/ If anyone is taking this up, we would be happy to hear about it. Best Regards Stefan Sayer & Atle Samuelsen [1] http://iptel.org/sems -- Stefan Sayer VoIP Services [EMAIL PROTECTED] www.iptego.com iptego GmbH Am Borsigturm 40 13507 Berlin Germany Amtsgericht Charlottenburg, HRB 101010 Geschaeftsfuehrer: Alexander Hoffmann _______________________________________________ Devel mailing list Devel@lists.openser.org http://lists.openser.org/cgi-bin/mailman/listinfo/devel
