[asterisk-dev] Jitter Buffer

[Pavel Jezek]

zoachien at securax.org wrote:
> We should not dejitter when possible, we should dejitter when we need 
> to because the receiving endpoint cannot do dejittering.
> Sip to iax should not dejitter, as the endpoints should dejitter,

I'm testing with ci$co 7912/sip and ci$co 7920/skinny, both phones using 
codec g729 and are connected over cdma connection (with jitter ~1000ms - 
mainly in upload direction i.e. phone->asterisk), asterisk is in the 
midle, sound quality is still very poor  :'(
maybe I have bad phones for this use (maybe with too small internal 
jitterbuffer), but I think, that proper dejittering at asterisk for both 
legs incomming from phones should help...
PJ

 


> the reason for this is that if we do dejittering in the middle, and 
> another time on the endpoints, the total delay because of dejittering 
> will be bigger than needed.
>
> A configuration file for applications might make sense, for example if 
> you do recordings because of line quality checks, you don't want the 
> jitter buffer to be active, as you want the real thing with the gaps 
> etc, but if you want recordings for monitoring people, you will want 
> it because it will be nicer to listen to.
>
> Zoa
>
>
> Pavel Jezek wrote:
>> Zoa, I think, that we should dejjitter when possible, always _before_ 
>> any processing within asterisk (sending to some app, bridging to 
>> channel, etc.),
>> is there any reason, why (in your example) dejjitter only sip-zap and 
>> not sip-iax?
>> PJ
>>
>>
>>
>> zoachien at securax.org wrote:
>>>
>>>> Unless we're planning on adding jbenable-type options to voicemail, 
>>>> meetme, monitor/mixmonitor and local channels (as a starting 
>>>> point), it would seem to make a LOT more sense to keep jbenable in 
>>>> all voip protocol configurations... (i.e. sip, iax2, skinny, etc.) 
>>>> -- that's where the jitter buffer actually exists.
>>>>
>>>> -A.
>>>>   
>>>
>>> I disagree with this, it's the only way you can choose when to have 
>>> dejittering and when not.
>>> You might for example want it for sip to zap but not from sip to 
>>> iax, thus if you set it in sip, you will have dejittering for sip in 
>>> your suggestion.
>>>
>>> Zoa
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