2.4 Create OpenSIPS Database and Configuration File. Realtime OpenSIPS - FreeSWITCH Integration Seen as an ethernet interface by the operating system. Sangoma Transcoding© 2011 Sangoma Confidential 29 Proxy Media © 2011 Sangoma Technologies 28 You most likely want to have “late negotiation” enabled © 2011 Sangoma Technologies 27. Set “inbound-proxy-media” in the SIP profile for a permanent solution. Set “proxy_media=true” variable before the bridge to enable it. Allows FreeSWITCH to pass-thru codec media that does not support © 2011 Sangoma Technologies 26. Only the “c=” part in the SDP is modified. Also called “transparent proxy mode” for the RTP. Recording will fail unless you manually put back FreeSWITCH on the media path © 2011 Sangoma Technologies 24īypass Media © 2011 Sangoma Technologies 25. uuid_media can re-invite FreeSWITCH on/off the media path. You can still play files! (uuid_broadcast). 
Set inbound-no-media or inbound-bypass-media in the SIP profile for a permanent solution © 2011 Sangoma Technologies 23.Enable by setting variable “bypass_media=true” before bridging.Media goes around FreeSWITCH (not through) directly between the endpoints.Media Modes© 2011 Sangoma Confidential 22 Late Negotiation © 2011 Sangoma Technologies 21 “ep_codec_string” contains the codecs offered by the endpoint © 2011 Sangoma Technologies 20.“inherit_codec” variable is available to try to use the codec from the B leg for the A leg.You can examine the incoming SDP and re-write SDP to fit your own needs.Negotiation will occur when incoming leg is answered (or requires early media) © 2011 Sangoma Technologies 19.Call will hit the dial plan without looking at codecs.“inbound-late-negotiation” set to “true” in the SIP profile.“Smarter” approach to codec negotiation.absolute_codec_str is a good brute-force approach © 2011 Sangoma Technologies 17Įarly Negotiation © 2011 Sangoma Technologies 18.“disable-transcoding” offers the same codec chosen for the inbound leg to the outbound leg.The codec is chosen matching SDP vs inbound-codec- prefs in the SIP profile.Use sip_codec_negotiation variable in the dial plan © 2011 Sangoma Technologies 15Ĭodec Negotiation © 2011 Sangoma Technologies 16.Use inbound-codec-negotiation in SIP profile.3 inbound negotiation algorithms – generous – greedy – Scrooge (Bah HUMBUG!).Late will happen when the leg is answered (or in pre- answer) © 2011 Sangoma Technologies 14.Early happens before call hits the dial plan.You can choose when this happens (early vs late).Decisions to be made to choose a codec for a call.Pass-thru codecs do not do transcoding © 2011 Sangoma Technologies 12Ĭodec Negotiation© 2011 Sangoma Confidential 13.Transcoding 2 SIP legs © 2011 Sangoma Technologies 11.Transcoding in one-legged call © 2011 Sangoma Technologies 10.
Is a must if you need: – Call recording – Tone detection – Play announcements or tones © 2011 Sangoma Technologies 9. Increases CPU usage (particularly if done in software). Required when endpoints have no codec in common. Pass-thru codec modules are dummies (mod_g729, mod_g723_1) © 2011 Sangoma Technologies 6įreeSWITCH Audio Codecs © 2011 Sangoma Technologies 7. Codec modules encode and decode from/to L16 format. FreeSWITCH core requires the media to be in L16 (signed linear, raw digital audio) format for manipulation (mixing, tone detection etc). G.722.1 Annex C - Ultra-wideband – 48kbps – 32kHz – 20ms, 40ms, 60ms © 2011 Sangoma Technologies 5. G.722 – Wideband – 48kbps, 56kbps and 64kbps – 16kHz (IANA clocks it at 8kHz due to historical error in RFC1890) – 10ms, 20ms, 30ms, 40ms … +. – 64kbps per second (Bit rate) – 8kHz (Sampling rate) – 10ms, 20ms, 30ms, 40ms … + (Packetization) G.711 (PCMU/PCMA, Ulaw/Alaw) – Narrowband. Packetization affects latency and bandwidth overhead © 2011 Sangoma Technologies 4. Codecs encode and decode voice for network transmission – Algorithm (compression technology) – Bit rate – Sampling rate – Packetization. 
Sangoma Transcoding © 2011 Sangoma Technologies 2Īudio Codecs© 2011 Sangoma Confidential 3. How to install g729 codec in freeswitch software#
Media Handling in FreeSWITCH Moisés Silva Software Engineer / Manager Audio Codecs
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