[Freeswitch-users] OPUS Codec

Wed May 10 17:38:51 MSD 2017

Anyone know on Polycom VVX's using OPUS, what is the sample rate? 8Khz or
48Khz or somewhere inbetween?

I looked a at call through VoIP Monitor, and it said OPUS48 as the codec.
Buy since "the OPUS
specification says that the SDP must always specify 48 kHz and 2 channels"
according to Kristian Kielhofner", I assume it just sadys OPUS 48 because
of this.

Like I mentioned, I though that G.722 between two Polycom's sounded better
than OPUS to my suprise. I assume this is because G.722 is at 16 kHZ, and
Polycom's opus is potentially at 8kHZ.
The softswitch we are using (Netsapiens) does not do any trasconding to my
knowledge, so the payload has to be whatever Polycom encodes/decodes at.

Is there a way to tell what kHz the Opus codec is running at on a Polcom
VVX, or by looked at a packet capture?

On Sat, May 6, 2017 at 1:26 PM, Kristian Kielhofner <kris at kriskinc.com>
wrote:

> FreeSWITCH can limit Opus to a configured sample rate but the OPUS
> specification says that the SDP must always specify 48 kHz and 2
> channels.
>
> OPUS is a combination of SILK and CELT, with the original PLC+FEC
> coming from SILK. There are effectively three modes in OPUS - SILK,
> CELT, and hybrid. It's not clear to me how well PLC+FEC works in the
> hybrid and CELT modes used at higher sample rates. I haven't looked at
> it specifically (or tested it) but my suspicion is that PLC+FEC works
> much better the closer you get to "pure" SILK mode, which is
> essentially what limiting the sample rate to 8 kHz does.
>
> On Sat, May 6, 2017 at 10:21 AM, Colin Morelli <colin.morelli at gmail.com>
> wrote:
> > Transcoding != resampling. Often times you will have to do both to
> convert
> > audio streams, where transcoding is the act of converting between the two
> > audio codecs' data format, and resampling is changing the sampling rate
> of
> > the audio (8khz in your case).  Opus is a completely different audio
> codec
> > than G.711. Even if they're both at 8 khz, you'll have to transcode
> between
> > the two, though you may be able to avoid the cost of resampling the
> audio to
> > a different rate.
> >
> > Opus can handle sampling rates from 8khz-48khz. Sampling rates make a
> huge
> > difference to audio quality (they'll effectively define the range of
> audio
> > frequencies you can capture). If you're running opus at a constant 8khz,
> the
> > reason G.722 sounds better is almost certainly because it's using a 16khz
> > sampling rate. Most likely if you run opus at 16khz, it'll sound similar
> to
> > G.722. If you have the capacity (and the devices support it), pushing
> opus
> > to super-wideband or full band (24khz/48khz sampling rates, respectively)
> > will yield much better audio quality.
> >
> > My guess (admittedly it's just an educated assumption), is that most
> WebRTC
> > companies are using fullband opus in VBR mode simply because this is the
> > default in WebRTC. Without mangling the SDP, this is what you're going to
> > get.
> >
> > Best,
> > Colin
> >
> > On Sat, May 6, 2017 at 10:41 AM, Colton Conor <colton.conor at gmail.com>
> > wrote:
> >>
> >> So what does today support FEC/PLC today?
> >>
> >> We tested two Polycom VVX phones with the opus codec, and overall
> thought
> >> that G.722 sounded much better than OPUS for some reason.
> >>
> >> So using Opus at 8 KHz, does that mean that there will be less or no
> >> transcoding to G.711 since its also in 8 KHz?
> >>
> >> What are most of the web only WebRTC companies using as far as OPUS
> goes?
> >> What bitrate and KHz?
> >>
> >> On Fri, May 5, 2017 at 8:33 AM, Brian West <brian at freeswitch.org>
> wrote:
> >>>
> >>> None of the hardware phones do FEC/PLC last I tested, Sonus has OPUS
> >>> support, but again no FEC/PLC support.
> >>>
> >>> /b
> >>>
> >>>
> >>> On Wed, May 3, 2017 at 2:16 AM, EL <fs.user at fordior.net> wrote:
> >>>>
> >>>>
> >>>> Yealink is supporting OPUS on several other models since firmware
> >>>> V81:
> >>>>
> >>>> Quote:
> >>>> "We will support opus on the standard V81 of
> >>>> SIP-T40P/T23P/T23G/T2 1(P) E2/T19(P) E2."
> >>>>
> >>>> Source:
> >>>> http://forum.yealink.com/forum/showthread.php?tid=
> 29650&pid=51262&mode=threaded
> >>>>
> >>>> I can confirm OPUS implementation on the 'T21P E2' model.
> >>>>
> >>>> --
> >>>> EL
> >>>>
> >>>>
> >>>> ____________________________________________________________
> _____________
> >>>> Professional FreeSWITCH Consulting Services:
> >>>> consulting at freeswitch.org
> >>>> http://www.freeswitchsolutions.com
> >>>>
> >>>> Official FreeSWITCH Sites
> >>>> http://www.freeswitch.org
> >>>> http://confluence.freeswitch.org
> >>>> http://www.cluecon.com
> >>>>
> >>>> FreeSWITCH-users mailing list
> >>>> FreeSWITCH-users at lists.freeswitch.org
> >>>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> >>>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/
> options/freeswitch-users
> >>>> http://www.freeswitch.org
> >>>
> >>>
> >>>
> >>>
> >>> --
> >>>
> >>> Brian West
> >>> brian at freeswitch.org
> >>>
> >>> Twitter: @FreeSWITCH , @briankwest
> >>>
> >>> http://www.freeswitchbook.com
> >>> http://www.freeswitchcookbook.com
> >>>
> >>> Book a phone call (CST)
> >>>
> >>> Allison prompts for FreeSWITCH:
> >>>
> >>> https://www.gofundme.com/allison-prompts-for-freeswitch
> >>>
> >>> Got Bugs? Report them here! | Reddit: /r/freeswitch
> >>>
> >>> T:+19184209001 | F:+19184209002 | M:+1918424WEST (9378)
> >>> Skype:briankwest
> >>>
> >>>
> >>> ____________________________________________________________
> _____________
> >>> Professional FreeSWITCH Consulting Services:
> >>> consulting at freeswitch.org
> >>> http://www.freeswitchsolutions.com
> >>>
> >>> Official FreeSWITCH Sites
> >>> http://www.freeswitch.org
> >>> http://confluence.freeswitch.org
> >>> http://www.cluecon.com
> >>>
> >>> FreeSWITCH-users mailing list
> >>> FreeSWITCH-users at lists.freeswitch.org
> >>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> >>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/
> options/freeswitch-users
> >>> http://www.freeswitch.org
> >>
> >>
> >>
> >> ____________________________________________________________
> _____________
> >> Professional FreeSWITCH Consulting Services:
> >> consulting at freeswitch.org
> >> http://www.freeswitchsolutions.com
> >>
> >> Official FreeSWITCH Sites
> >> http://www.freeswitch.org
> >> http://confluence.freeswitch.org
> >> http://www.cluecon.com
> >>
> >> FreeSWITCH-users mailing list
> >> FreeSWITCH-users at lists.freeswitch.org
> >> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> >> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/
> options/freeswitch-users
> >> http://www.freeswitch.org
> >
> >
> >
> > ____________________________________________________________
> _____________
> > Professional FreeSWITCH Consulting Services:
> > consulting at freeswitch.org
> > http://www.freeswitchsolutions.com
> >
> > Official FreeSWITCH Sites
> > http://www.freeswitch.org
> > http://confluence.freeswitch.org
> > http://www.cluecon.com
> >
> > FreeSWITCH-users mailing list
> > FreeSWITCH-users at lists.freeswitch.org
> > http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> > UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> > http://www.freeswitch.org
>
>
>
> --
> Kristian Kielhofner
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
>
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20170510/ce33bcde/attachment-0001.html 