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IP Softphone : Getting rid of the Delay 1

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PDHall

MIS
May 24, 2002
72
AU
Morning all!
I've recently installed an IP Softphone to my PC in order to do some development work with it. The problem that I have is that I get quite a noticable delay when using the phone (about a second) and was wondering if there were any easy work-arounds for this. I've heard that there is an echo cancellation feature that we could activate however we cant find it!!!!
We're using G3R v9.5

Any ideas would be great
 
Some questions to give me an idea:

1.Is your PC equipped with a fully Duplex sound-card and do you use a PC-headset?
2.Did you install all the IPSoftphone's codec's on your PC?
3.How's your network performing?
4.When hearing the echo, did you call to a digital phone, another IP phone and was it in the same room?

These questions may seem a bit silly, but ehr.. trial and error ey ;)

Hope 2 hear.

Kind Regards,
Maarten Copini


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Marteen,
Nothing is silly here mate!
PC - Top-Notch full duplex soundcard and plantronics recommended headset
IPSoftphones Codec : Went through the normal instal, would this have installed the codec for me or can I download it somewhere?
Network - Gigabit network no probs there!
Phoned a variety of phones, internal, external and mobile, echo was worse on mobile but I expected that

Any ideas?
 
Which CODEC's do you use on the Definity? You could try to use a different one for your IPSoftphone.
Could help you on the Definity side, but as far as the network's concerned...sounds ok. Which release IPSoftphone did you install? 2 or 3?
Kind Regards,
Maarten Copini


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Hello PDHall,

There are several options, but first, you must understand that (especially with softphones) you will ALLWAYS notice a delay when using an IP (soft)phone, if you can see the other party you're talking to. This is because the codecs need some processing time, and the network (no matter how fast) also introduces a little latency, and of course the PC itself (you speak into the headset, this goes to the soundcard, gets digitalized, goes to the codec, gets encoded, and after that it enters the queue for the NIC).
The delay should not be noticable if you speak to someone you can't see, the human brain can adapt to latencies smaller than 300 or 350 milliseconds without you even noticing it, but it gets hard if you see the other partie's mouth moving, yet receive the sound half a second later :)

It also matters wich codec you use, when using f.i. G.729(A), the voice is not only encoded, but also compressed, wich takes a little processing, and thus delay (from 20 to 70 mS), and this happens on both sides of the line (endpoints must use the same codec, or it must be translated somewhere).
If you are using G.729 now, wich is normally unnecesary on a LAN, you can try switching to G.711, wich is an uncompressed codec and has virtually no extra delay. Bandwidth for G.729 (for a real call, so duplex, overhead and stuff like that) is about 25 Kbps, and for G.711 it is about 130 Kbps. The actual bandwidth can vary a little depending on whether features like silence surpressing etc. are used or not.

Another cause of delay can be the jitter-buffer, the jitter-buffer compensates for variations in delay(latency) by introducing a default latency higher than the highest latency value (so if the latency varies between 20 and 120 ms, you can set the jitter-buffer to 130 ms. This causes the conversation to "feel" better, because like said before, it is easy for the brain to compensate for a small delay, but when this delay varies too much, you will notice it). Default is "Automatic", but you can also set it manually.
There are more settings in the softphone you can experiment with, my experience is that most problems are solvable that way, every PC differs, and there's no real good "default" value that works on all PC's/soundcards etc etc.
You can find them under "Tools" > "Audio" > "Options". You can also try reinitiating the audio-wizard, and when on a call, you can use "Status" to see realtime values for latency, jitter (-buffer) etc, that might help to solve your problem.

Sorry for the long read, I must try to say more with less words, but I'm not yet succeeding :) If you still haven't had enough reading, I would strongly propose reading the new "Network Requirements" (V2), wich you can get from the BP portal, or by asking me.

Cheers,
Nico
 
Quite a story Nico, ;)
wilde er nog niet aan beginnen, maar

You're completely right as always. :)
Kind Regards,
Maarten Copini


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Yeah, well... I didn't tell you all there is to it:

As a result of the antimatter converter assembly that tries to establish an adaptive interface link with the bioregenerative field, the Bussard collectors can sometimes cause a space-time anomaly, wich results in some delay.

But I would first try the other options I've mentioned before digging into this one...

:)

Nico
(Scott me over, Beamy!)
 
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