[Freeswitch-users] mod_portaudio send 3 rtp packet/60ms instead of1 packet/20ms

Csaba Zelei csaba.zelei at gmail.com
Mon May 5 09:38:39 PDT 2008


With a little hack I can make mod_portaudio to send rtp packets with 
~24ms, ~16ms delay alternately on linux. This result in a constant 4ms 
jitter but its better than the original. (diff attached)
However on windows the delta between rtp packets is 15-32 ms randomly, 
with occasionally high 70-100ms delta.
I also tried to tweak the windows timer without success.
Does anybody has any idea how to make windows xp more accurate?

Sluschny, Thomas wrote:
> as you can see here:
>
> _http://jira.freeswitch.org/browse/MODENDP-40_
>
> i have this problem all the time (the error mentioned in this issue 
> was only related with this).
>
> It has to do with windows handle sleep() method, you has say sleep(1) 
> for 1ms but on my
>
> machine it waits 15ms (it depends on your hardware, other PCs behave 
> different!). So i tested around with high performance counters.
>
> For now i ignore that problem an set jitterbuffers on other device big 
> enough.
>
> Thomas
>
>
> ------------------------------------------------------------------------
> *Von:* freeswitch-users-bounces at lists.freeswitch.org 
> [mailto:freeswitch-users-bounces at lists.freeswitch.org] *Im Auftrag von 
> *Zelei Csaba
> *Gesendet:* Donnerstag, 24. April 2008 19:05
> *An:* freeswitch-users at lists.freeswitch.org
> *Betreff:* [Freeswitch-users] mod_portaudio send 3 rtp packet/60ms 
> instead of1 packet/20ms
>
> Dear all,
>
> I tried to use FS in client mode, starting calls with mod_portaudio to 
> our providers gateway ( a Cirpack softswitch )
> I experienced that there is 2-3 sec delay in the call, its choppy and 
> robot like.
> I tested it with a softphone, and an ip phone and everything was fine. 
> I traced back the problem to mod_portaudio sending 3 rtp packet in 
> 60ms instead of 1 packet/20ms.
>
> Here is an rtp statistic from a call: (see 
> http://pastebin.freeswitch.org/4307 for the complete list and sip trace)
>
> Packet    Sequence    Delta (ms)   
> 42  26138    0.00   
> 43    26139    0.02   
> 46    26140    45.69
> 47    26141    0.02   
> 48    26142    2.96   
> 52    26143    56.31
> 53    26144    5.75   
> 54    26145    0.02   
> 58    26146    51.99
> 59    26147    0.03   
> 60    26148    2.96   
> 63    26149    42.95
> 65    26150    17.06
> 66    26151    0.02   
> 67    26152    2.90   
> 71    26153    56.99
> 72    26154    0.03   
> 73    26155    0.02   
>
> Did anyone else experience similar problems?
> Is this the desired behaviour, because portaudio get data in 60ms 
> interval or can I set it to 20ms somehow?
>
> Thanks,
>
> Csaba Zelei
>
>
> ------------------------------------------------------------------------
>
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