[Asterisk-Users] G729 codec

todd tkgunfedora at comcast.net
Tue May 24 19:12:41 MST 2005


Steve
Thank you for the enlightenment, that explains allot and it even makes 
sense.
 So I take it that means that there is no other version as far as Asterisk 
is concerned; it only is designed to use G.729A, correct?
Do you know if the data rate,  kbps,  is a constant or does it fluctuate? 
For example I have heard with a Avaya design if no one was speaking it could 
get down to practically nothing while holding a line open. Does Asterisk 
have the ability to use less then 8 kbps with the G.729?

TKG


----- Original Message ----- 
From: "Steve Underwood" <steveu at coppice.org>
To: "Asterisk Users Mailing List - Non-Commercial Discussion" 
<asterisk-users at lists.digium.com>
Sent: Tuesday, May 24, 2005 5:20 PM
Subject: Re: [Asterisk-Users] G729 codec


> Actually G.729A is a reduced complexity version, and G.729B is a version 
> with silence suppression. The data rate while sending voice is exactly the 
> same, although the quality of G.729B should be a little higher. However 
> the average rate for B can be lower if the silence suppression is used. 
> Right now Asterisk doesn't make use of that silence suppression, so it 
> makes not difference.
>
> Regards,
> Steve
>
>
> Zoa wrote:
>
>>
>> Thats incorrect,
>>
>> a and b are both the same, 8kbps.
>> a and b are just another way of calculating it, the result is the same
>> and a and b are compatible.
>>
>>
>> todd wrote:
>>
>>>
>>> ----- Original Message ----- From: "todd" <tkgun-zaurus at comcast.net>
>>> To: "Asterisk Users Mailing List - Non-Commercial Discussion"
>>> <asterisk-users at lists.digium.com>
>>> Sent: Tuesday, May 24, 2005 12:34 PM
>>> Subject: Re: [Asterisk-Users] G729 codec
>>>
>>>
>>>> Andrew
>>>> Thanks for the reply-
>>>> Forgive my ignorance in this area but from what I have been told by
>>>> the client was that G.729 b used less over all bandwidth on average )
>>>> then G.729 A.
>>>> Correct me if I am wrong but the way it was laid out to me was G.729
>>>> B = (5.? kbps-8 kbps) G.729 A= (8 kbps -13kbps) , these of course
>>>> stats form Avaya devices, maybe for whatever reason Asterisk capable
>>>> of keeping it at 8?
>>>> This is way out of my area, I would love to be wrong and be able to
>>>> use A if it can perform they way they want.
>>>> The reason it is an issue they serve international circuits and every
>>>> bit counts and adds up with the volume they do.
>>>> TKG
>>>>
>>>>
>>>> ----- Original Message ----- From: "Andrew Kohlsmith"
>>>> <akohlsmith-asterisk at benshaw.com>
>>>> To: <asterisk-users at lists.digium.com>
>>>> Sent: Tuesday, May 24, 2005 6:55 AM
>>>> Subject: Re: [Asterisk-Users] G729 codec
>>>>
>>>>
>>>>> On May 22, 2005 04:46 pm, todd wrote:
>>>>>
>>>>>> Thanks for the info: do you know if  the g729 codec for Asterisk is
>>>>>> limited
>>>>>> to only the G.729A version. Is there G.729 B available for Asterisk?
>>>>>
>>>>>
>>>>>
>>>>> Does it matter?
>>>>>
>>>>> g729 has fixed-point and floating-point implementations.  The data
>>>>> coming out
>>>>> the back end is the same.  Either a is floating-point and b is
>>>>> fixed-point or
>>>>> the other way 'round (I can never remember).
>>>>>
>>>>> It should not make one whit of difference which one you use to
>>>>> generate the
>>>>> g729 stream.  Do you have a specific reason to need one over the 
>>>>> other?
>>>>>
>>>>> -A.
>>>>
>
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