Hi, the problem is, the device (a VoLTE phone) will ALWAYS offer AMR-WB and AMR-NB and we will need to do transcoding to G722 / G711 in most cases (unless the B-Party actually offers AMR-WB/AMR-NB). The Answer may be pure G711 (RTPEngine will do Transcoding G711 <=> AMR-WB [meaningless]) or G722 (RTPEngine will do Transcoding G722 <=> AMR-WB [Makes sense]) or AMR-NB/-WB (no Transcoding [ideal]). If I could limit the Answer from RTPEngine to contain only AMR-NB, that would ideal, as AMR-NB has less complexity, than transcoding into AMR-WB and it would additionally save bandwidth (which is important in our case).
However, I should mention that I am already more than happy with the current result. Transcoding is working great, even with AMR/AMR-WB! Thanks, Carsten -- Carsten Bock I Managing Director ng-voice GmbH Millerntorplatz 1 I 20359 Hamburg I Germany www.ng-voice.com Mobile +49 (0)179-20 21 244 I Direct +49 (0)40-52 47 593-40 I Fax +49 (0)40-52 47 593-99 Sitz der Gesellschaft: Hamburg Registergericht: Amtsgericht Hamburg, HRB 120189 Geschäftsführer: Carsten Bock, Dr. David Bachmann Ust-ID: DE279344284 Hier finden Sie unsere handelsrechtlichen Pflichtangaben: http://www.ng-voice.com/imprint/ Am Mi., 22. Mai 2019 um 01:17 Uhr schrieb Richard Fuchs <rfu...@sipwise.com >: > On 21/05/2019 18.42, Carsten Bock wrote: > > Hi Richard, > > > > Thanks for your reply, understood. > > > > The issue is following (not really an issue, more an optimization): > > At the moment of the offer, I simply don't know, what will be > > supported by the callee. G711 is however always supported, that's why > > I don't want to strip it. I send the call to our upstream provider; if > > he sends it to Telefonica, we get an answer with G722 and G711. If he > > sends it to Deutsche Telekom, the answer is only G711. However, we > > don't know, if it's gonna be Telefonica or Deutsche Telekom... > > > > I was thinking about avoiding uneccessary RTP traffic (in HD) between > > RTPEngine and the device in case of an outbound call. From a > > signalling perspective, I get the right result, if I use > > sdp_remove_codecs() in my reply. However, that won't work, since the > > RTP stream sent from RTPEngine to the device is in HD, regardless of > > the signalling. > > Maybe you want to make your transcoding options also dependent on > whether G.711 was present in the original offer, and/or in what order > the codecs were listed? Rtpengine won't do transcoding if both sides > support the same codec, even if other codec pairings are possible > (unless `always-transcode` is given). Are you using that option? Are you > using other options to reorder codecs in the offer? Because normally the > first supported codec will be used, and rtpengine adds transcoding codec > offers to the end of the list. So they should only be used if no other > codec is supported by the callee, unless the callee ignores the listed > codec preferences, or codecs were reordered, or `always-transcode` was > used. > > Cheers > > > _______________________________________________ > Kamailio (SER) - Users Mailing List > sr-users@lists.kamailio.org > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users >
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