[asterisk-users] Which cause less CPU usage: GSM or wav??

[Thomas Kenyon]

Barton Fisher wrote:
> Thanks, OK, a bit confused....  The cards are TE410P.  I really don't
> see how the set a codec for this, other than it might default to
> something in code like ulaw.  Any clue on how to verify codec in use
> during a call?
> 
G.711ulaw and G.711alaw are the audio transmission methods used for
ISDN. If you have a T1 line then the transmission method is G.711ulaw.

I've been told that if you play a ulaw signal down an alaw line (T1
signal down E1) then at the other end the voice sounds a bit like a
dalek. (Iit's very hard to do this with asterisk since it automatically
transcodes between endpoints).

The lack of a performance hit is quite striking when you have a
recording playing back as a native format rather than being transcoded.
(well, it's quite striking when you have thousands of them running
simultaneously).

> Bart
> 
> Steve Totaro wrote:
>> Michiel van Baak wrote:
>>  
>>> On 10:28, Sun 09 Sep 07, Barton Fisher wrote:
>>>      
>>>> I have 4 TDM T1's going in to a IVR system.  The IVR messages are
>>>> recorded .wav format - The system appears to crap out at about 40
>>>> calls - Would using GSM or some other format help save CPU cycles?
>>>> Using 1.2, Dual Xeon and 2GB ram
>>>>           
>>> depends on what codec the T1 is using.
>>> Best to transcode the ivr sounds to the same codec to
>>> prevent on-the-fly transcoding by asterisk.
>>>
>>>       
>> The answer is going to ulaw or alaw depending where you live.  T1
>> should most likely be using ulaw so make everything ulaw, end to end.
>>
>> Thanks,
>> Steve Totaro
>>
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