Stefan and Atle, Yes, it's very interesting work indeed, thank you for publishing it.
Stefan Sayer wrote: > [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 Regards, -- Maksym Sobolyev Sippy Software, Inc. Internet Telephony (VoIP) Experts T/F: +1-646-651-1110 Web: http://www.sippysoft.com _______________________________________________ Devel mailing list Devel@lists.openser.org http://lists.openser.org/cgi-bin/mailman/listinfo/devel
