No subject

switching from ulaw to g729 for a normal mobile-to-mobile call?


On Tue, Jan 17, 2012 at 9:37 PM, Steve Underwood <steveu at coppice.org> wrote=
:
> On 01/16/2012 03:59 PM, Roi Stork wrote:
>>
>> Hi,
>>
>> We noticed a very sharp drop in voice quality when using digium g729a
>> codec. The problem seems to happen if the A channel (caller's channel)
>> is a landline/mobile number contacted using the same outgoing provider
>> (as a local channel). It sounds like listening to a mono speaker on
>> low volume.
>
> You have conflated two very different things there - landline calls and
> cellular calls. A land line to a VoIP user by G.729A should sounds pretty
> good. A cellphone to a VoIP user by G.729A should sound *far* worse.
> Converting between two different low bit rate codecs really hits the
> quality, and all cellphone calls are low bit rate.
>
>> If I use a softphone that is directly registered to our asterisk box
>> the audio quality improves, the words come out more clearer and
>> louder.
>
> You are conflating two things again. Quality and volume are largely
> independent issues.
>
>> I also asked my provider to test call me using their Cisco as5300
>> system and g729 codec and compared it with ulaw. The difference is
>> unnoticable.
>
> Try that again. If you really can't hear the difference you should check
> carefully that the system is working as you think it is. If it is, maybe =
you
> should consult a doctor. G.729A is considerably poorer than ulaw.
>
> Steve
>
>
>
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