<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">A big thanks to Tamas and Steve Underwood for putting this new page together:<div><br></div><div><a href="http://wiki.freeswitch.org/wiki/VAD_and_CNG">http://wiki.freeswitch.org/wiki/VAD_and_CNG</a></div><div><br></div><div>Mike</div><div><br><div><div>On Sep 15, 2008, at 5:14 AM, Sluschny, Thomas wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>thank you very much Tamas,<br>i found this infos very useful :) <br><br>-----Ursprüngliche Nachricht-----<br>Von: freeswitch-users-bounces@lists.freeswitch.org [<a href="mailto:freeswitch-users-bounces@lists.freeswitch.org">mailto:freeswitch-users-bounces@lists.freeswitch.org</a>] Im Auftrag von Tamas<br>Gesendet: Samstag, 13. September 2008 14:31<br>An: <a href="mailto:freeswitch-users@lists.freeswitch.org">freeswitch-users@lists.freeswitch.org</a><br>Betreff: Re: [Freeswitch-users] VAD and CN question<br><br><br>Hello,<br><br>to answer for my own email - for other who might be interested...<br><br><br>Tamas írta:<br><blockquote type="cite">Hello,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I've talked about CNG, VAD with Anthony and Brian already but I still<br></blockquote><blockquote type="cite">have a mess in it and don't really know how it works.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Could anybody explain the practical side of these magic options?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">1. What does suppress_cng=true do exactly? (yep, I know it suppresses<br></blockquote><blockquote type="cite">CNG, but what does this mean? Won't send out the CN/8000 rtpmap in SDP?)<br></blockquote><blockquote type="cite"><br></blockquote>suppress-cng and suppress_cng are used to manage the sending of CN RTP<br>packets after agreement through SDP.<br><br><blockquote type="cite">2. What do VAD settings do in sofia profile? I've read<br></blockquote><blockquote type="cite"><a href="http://wiki.freeswitch.org/wiki/Sofia.conf.xml">http://wiki.freeswitch.org/wiki/Sofia.conf.xml</a><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"> <!-- <param name="vad" value="in"/> --><br></blockquote><blockquote type="cite"> <!-- <param name="vad" value="out"/> --><br></blockquote><blockquote type="cite"> <!-- <param name="vad" value="both"/> --><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">What do these options do in practice? Can FS detect silence (e.g. no<br></blockquote><blockquote type="cite">RTP?) and than what can it do with?<br></blockquote><blockquote type="cite"><br></blockquote>When VAD is turnd on, FS checks on the given channel for incoming or/and<br>outgoing channel (depends on the settings) and when detects silence,<br>stops sending out RTP.<br><br><blockquote type="cite">3. I found undocumented options rtp_enable_vad_in, rtp_enable_vad_out<br></blockquote><blockquote type="cite">for sofia which might be the per call settings for point 2. ? If this is<br></blockquote><blockquote type="cite">correct, what will this do?<br></blockquote><blockquote type="cite"> <action application="set" data="rtp_enable_vad_in=true"/><br></blockquote><blockquote type="cite"> <action application="set" data="rtp_enable_vad_out=true"/><br></blockquote><blockquote type="cite"> <action application="bridge" data="sofia/....."/><br></blockquote><blockquote type="cite"><br></blockquote>These settings are the same as in 1. but can be used per call.<br><br><blockquote type="cite">4. What will FS do when one side of the bridge supports CN but the other<br></blockquote><blockquote type="cite">doesn't?<br></blockquote><blockquote type="cite">E.g. softphone->FS->GW (sends CN packets)<br></blockquote><blockquote type="cite">the softphone does not support CN<br></blockquote><blockquote type="cite">Would it be possible to turn on comfort noise generation in FS for the<br></blockquote><blockquote type="cite">side which cannot handle CN?<br></blockquote><blockquote type="cite"><br></blockquote>When on side does not support CN, FS simply won't forward CN RTP<br>packets. Comfort noise generation into media channel in FS is possible with<br>bridge_generate_comfort_noise=true<br>added in r9543. More about on <a href="http://wiki.freeswitch.org/wiki/VAD_and_CNG">http://wiki.freeswitch.org/wiki/VAD_and_CNG</a><br><br><blockquote type="cite">5. Is it possible to let FS detect silence and on one leg send CN<br></blockquote><blockquote type="cite">packets insted of RTP?<br></blockquote><blockquote type="cite">E.g. softphone->FS->GW (sends CN packets)<br></blockquote><blockquote type="cite">the softphone does not support CN, but for saving bandwidth it would be<br></blockquote><blockquote type="cite">good to have silence detection and in case of silence FS lets send CN<br></blockquote><blockquote type="cite">instead of RTP.<br></blockquote><blockquote type="cite"><br></blockquote>Yes, possible. VAD has to be turned on that channel and both sides have<br>to agree on CN RTP packets (in SDP).<br><br><blockquote type="cite">Sorry for my dump questions, I would like to understand the whole picture.<br></blockquote><blockquote type="cite"><br></blockquote>I hope I'm on the right way :)<br><br><blockquote type="cite">I would like to add the clarification to FS wiki to lets other have less<br></blockquote><blockquote type="cite">troubles (with endpoints on one side supporting VAD/CNG and endpoints on<br></blockquote><blockquote type="cite">other side not supporting VAD/CNG, e.g. CallWeaver)<br></blockquote><blockquote type="cite"><br></blockquote>Check<br><a href="http://wiki.freeswitch.org/wiki/VAD_and_CNG">http://wiki.freeswitch.org/wiki/VAD_and_CNG</a><br><blockquote type="cite">Thanks in advance!<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Regards,<br></blockquote><blockquote type="cite"> Tamas<br></blockquote><blockquote type="cite"><br></blockquote><br></div></blockquote></div></div></body></html>