Hey Michael,

That means a lot coming from the CODEC guru !

Here is a nice reference:

https://developer.skype.com/resources/SILKDataSheet.pdf

If only there was a SILK support backport for Asterisk 1.8 .

Lonnie


On Nov 27, 2012, at 2:56 PM, <mgra...@mstvp.com> <mgra...@mstvp.com> wrote:

> I'd expect SILK to outperform iLBC at similar bit rates.
> 
> Michael Graves
> mgraves  mstvp.com
> o(713) 861-4005
> c(713) 201-1262
> sip:mjgra...@mstvp.onsip.com
> skype mjgraves
> 
>> -------- Original Message --------
>> Subject: [Astlinux-users] Mobile SIP clients, Bria vs. Groundwire
>> From: Lonnie Abelbeck <li...@lonnie.abelbeck.com>
>> Date: Tue, November 27, 2012 1:25 pm
>> To: AstLinux Users Mailing List <astlinux-users@lists.sourceforge.net>
>> 
>> 
>> Greetings,
>> 
>> I have been testing mobile SIP client access to AstLinux, and the combo of 
>> SIP TLS, plus SRTP encryption, using either Bria or Groundwire works well 
>> for both incoming and outgoing calls. Possibly others have additional 
>> comments...
>> 
>> Bria iPhone Edition
>> http://www.counterpath.com/bria-iphone-edition.html
>> 
>> Groundwire, Business Caliber SIP for the iPhone
>> http://www.acrobits.cz/11/acrobits-groundwire-for-iphone
>> 
>> Either work quite well on my iPod Touch 4th gen.  I'm not the first to 
>> mention this here on this list, thanks to others, you know who you are. :-)
>> 
>> Groundwire has a lot more features than Bria, but I personally find that 
>> Bria's voice quality is noticeably better than Groundwire's voice quality, 
>> which is still OK.  If you require Groundwire's features, go with it, if the 
>> simpler Bria suits your needs, go with Bria.  Your milage may vary.
>> 
>> The key feature of both Bria and Groundwire, using iOS at least, is support 
>> of a power efficient background TCP process for handling incoming calls, not 
>> requiring the power hungry technique of the whole application running in the 
>> background.  Groundwire also supports push notifications for incoming calls, 
>> but this requires Groundwire to upload your SIP credentials to their server, 
>> something I'm not willing to do, particularly when SIP/TLS works so well.
>> 
>> CODEC's
>> 
>> My standard setting is using G.711 CODEC, over WiFi, either via a public AP 
>> or using a Verizon LTE MiFi.  This works the best for me, but not the most 
>> efficient.
>> 
>> I tried using the iLBC CODEC, with mixed results.  The common issues with 30 
>> ms iLBC packet length in Asterisk vs 20 ms for G.711 and transcoding.
>> 
>> iLBC (30ms packet) to G711 (20ms) ULAW transcoding sounds "robotic"
>> https://issues.asterisk.org/jira/browse/ASTERISK-18094
>> 
>> normally using the iLBC CODEC it sounds 'pretty good', though noticeable 
>> artifacts compared to G.711 .  Additionally when placing callers on hold, 
>> etc. I see (Asterisk 1.8)...
>> -- many of these --
>> Nov 27 12:09:06 gw-lan local0.warn asterisk[4679]: WARNING[18388]: 
>> translate.c:206 in framein: no samples for ilbctolin
>> --
>> -- and these --
>> Nov 27 12:09:20 gw-lan local0.warn asterisk[4679]: WARNING[18388]: 
>> translate.c:225 in framein: ilbctolin did not update samples 0
>> Nov 27 12:09:20 gw-lan local0.warn asterisk[4679]: WARNING[18388]: 
>> codec_ilbc.c:104 in ilbctolin_framein: Huh?  An ilbc frame that isn't a 
>> multiple of 50 bytes long from RTP (60)?
>> --
>> 
>> Are there other tricks getting iLBC to transcode between 30 and 20 ms 
>> properly ?  Possibly later Asterisk versions than 1.8 ?
>> 
>> Possibly down the road, when Asterisk 11 is production quality, is the 
>> (Skype) SILK CODEC the solution ?
>> 
>> Asterisk 10 Codecs and Audio Formats
>> https://wiki.asterisk.org/wiki/display/AST/Asterisk+10+Codecs+and+Audio+Formats
>> 
>> Notice the "codec_silk.so" is provided as a binary by Digium for free, I'm 
>> not sure we could automatically provide it in the AstLinux image for the 
>> same reason Digium doesn't.
>> 
>> Does the lower bitrate SILK CODEC provide the best solution vs iLBC ?  Bria 
>> currently supports both a NB and WB SILK CODEC.
>> 
>> Comments?
>> 
>> Lonnie
>> 
>> 
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> ------------------------------------------------------------------------------
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