[Freeswitch-users] Audio Codecs over Mobile Connection

Bote Man bote_radio at botecomm.com
Sat Jan 30 22:48:09 MSK 2016

If you are using mobile data to set up your own SIP calls, then you are now struggling through the same battles that the cellular carriers conquered for the past 2 decades. L LTE should help greatly with this, as the carriers in the U.S. are moving to send everything over LTE.


If it is a mobile voice call, then you are at the mercy of the codec audio that the cellular carrier chose.





From: Volodymyr Fedorov
Sent: Saturday, 30 January, 2016 12:27
Subject: Re: [Freeswitch-users] Audio Codecs over Mobile Connection


Question is what kind of mobile connection do you use? If it is UMTS/CDMA, so even not compressed codecs like g711u/a or g722 are working fine. Regarding bandwidth usage you have to choose between SILK,Opus or even old one iLBC or GSM.




On Sat, Jan 30, 2016 at 9:40 AM, Stanislav Sinyagin <ssinyagin at gmail.com> wrote:

Of course jitter buffer is independent from codec, but its functionality affects the quality.

Yes SILK is inherited by Opus, but in general SILK is much cheaper in terms of CPU cycles for encoding and decoding.

You can see the difference here: https://txlab.wordpress.com/2015/04/10/testing-freeswitch-performance-on-scaleway-c1/

On 30 Jan 2016 06:41, "Oleg Stolyar" <olegstolyar at gmail.com> wrote:

Thanks Stanislav!


I understand that jitter buffer is not necessarily codec dependent and that SILK is actually the foundation of Opus, so I assume their quality is comparable.


On Fri, Jan 29, 2016 at 8:26 PM, Stanislav Sinyagin <ssinyagin at gmail.com> wrote:

add SILK to the list (it's actually what Skype uses), and jitter buffer.

but I don't have much practical experience.

The quality of the sound depends also on the particular SIP client

On Fri, Jan 29, 2016 at 11:32 PM, Oleg Stolyar <olegstolyar at gmail.com> wrote:
> Hi guys,
> does anyone have experience using different codecs to reduce choppiness and
> metallic/robotic sound when connecting to FreeSWITCH from a mobile device?
> I know both OPUS and G.722 have packet loss concealment but I wonder if
> someone actually has practical experience with different codecs over iffy
> mobile connections.
> OPUS vs. G.722 vs G.711

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