Robert I think you've all but proven the issue, if the hard phone works - same server, same internet connection, same everything - except - the phone itself (replaced Ekiga with this phone temporarily) and there is no delay - thus - no echo, the PC is the issue.
Exactly how to track the delay inside the PC from mike/speaker through ekiga to the network card - I'll have to defer to the SW guys. I use lots of older PCs with ancient sound cards, and these usually are a likely source of latency. At least you can check the PC->server or PC->PC latency - a simple test is ping - see what the maximum and average , example, send 5 frames: sad...@tau:~> ping -c 5 ekiga.net PING ekiga.net (86.64.162.35) 56(84) bytes of data. 64 bytes from ekiga.net (86.64.162.35): icmp_seq=1 ttl=56 time=34.4 ms 64 bytes from ekiga.net (86.64.162.35): icmp_seq=2 ttl=56 time=96.4 ms 64 bytes from ekiga.net (86.64.162.35): icmp_seq=3 ttl=56 time=34.1 ms 64 bytes from ekiga.net (86.64.162.35): icmp_seq=4 ttl=56 time=34.7 ms 64 bytes from ekiga.net (86.64.162.35): icmp_seq=5 ttl=56 time=43.0 ms --- ekiga.net ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4001ms rtt min/avg/max/mdev = 34.106/48.542/96.460/24.190 ms check to see if the PC network card has errors: netstat -s ifconfig ethtool -S eth0 /mii-diag (depends on card/distro) Note the max and average delay. anything over approx. 25ms - You have a chance of hearing the echo. Now how to do this between application and network interface - I'll have to pass. Hope this helps. Robert Ingraham wrote: > > After fiddling around a little bit, I think the real problem is not so > much echo as latency, and I think the problem is probably with the > Ekiga/Jaunty combination. I set the system audio settings and the > Ekiga audio settings both to the same thing, in this case to > Nvidia/Alsa (my sound card is Nvidia), and I lowered the jitter buffer > from 500 (the default) to 220. This eliminated a lot (not all) of the > echo. If I lower the jitter buffer any more, the calls begin to break > up. However, there is still a very bad latency (delay) problem. Very bad. > > As a test, I unplugged my laptop from the ethernet wire, and plugged > the same ethernet wire into a VOIP hard phone, configured to use the > same server. On the VOIP hard phone, there is no echo, no delay, and > the calls are clear. No noticible latency problem at all. > > I should mention that I used Ekiga under Ubuntu Intrepid, and I did > not have the Latency/Echo problems. It only started after I upgraded > to Jaunty beta. Any thoughts? > > > > On Sat, Apr 4, 2009 at 3:06 AM, Shawn Adams <[email protected] > <mailto:[email protected]>> wrote: > > Robert, > > It's not a bandwidth issue. > > There are two main sources of echo in telephony networks: acoustic > echo > and line echo. Acoustic echo is generated on any phone (IP phone or > analog) when there is feedback from the speaker to the microphone. > > This is particularly noticeable on many speaker phones. Line echo is > very common in the PSTN network, and this most commonly occurs when > there is a two-wire to four-wire conversion in the network (for > example, > where analog is converted into T1 or E1). In the good old telephone > network, the delay is so small, the human ear doesn't notice. > > They have also 50+ years experience with echo cancellation, which > works > well on analog signals, but is more difficult with VOIP. > > Leak-through happens only in analog circuits. VOIP frames do not leak. > > Echo is almost always happening at the opposite end of where the > echo is > perceived. It might be happening at the PSTN gateway as well. > > If you've set your mute button, but the other side still hears > echo, it > is possibly a leak in your VOIP phone or sound card/drivers area, > or the > gateway. > > The gateway to the PSTN is just another source of delay, they more > delay > - the more perceptable the echo. > > > #1 does a purely SIP/VOIP call have the echo ? > > - if NO - the echo may be induced at the PSTN gateway, in each case, > check the round trip delay between your phone and the target. > > #2 what is the round trip delay from your phone to the PSTN gateway ? > > - there is almost always echo on a good old fashioned telephone, > but you > don't notice it because the delay is <25ms > > - if you can somehow reduce the round trip delay - this might minimize > the perceived echo, 150ms is usually a good rule-of-thumb as maximum > tolerable for VOIP calls. > > #3 it is possible the echo is in the sound card/devices/drivers - I've > had luck playing with volume levels disabling of the various sound > card > devices - capture device, PCM volume, etc... > > So see if you can isolate whether the echo is at the gateway, or > at your > phone. There may be little you can do about the gateway, except to > complain to the provider. If it's at the phone - take a look at the > various devices/pulse audio, etc... > > My 2 cents.... > > > Hope this helps. > > Best regards, > > Robert Ingraham wrote: > > I have read previous posts on this subject, but I still cannot > resolve > > the problem. I use Ekiga to make PC-to-Phone calls. I use a headset. > > I am running Ubuntu Jaunty beta, with PulseAudio. When I make > calls, I > > can hear fine, with no echo, but the people I am talking to > complain of > > a very bad echo. This includes both landlines and cellphones. > There is > > also a delay between when they talk, and when I hear them. The > headset > > I use has a mute button, but even if I mute my end, the other person > > still hears an echo. I have tried enabling both "echo > cancelation" and > > "silence detection" in Ekiga's preferences, but this has had no > effect > > at all on the echo. Ekiga's codec preferences are set to use Speex > > 16khz codec. I have a very good Comcast cable connection, with > download > > rates in the 750mb-1gb range. Anyone have any idea how to fix this? > > Would turning off PulseAudio help? > > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > ekiga-list mailing list > > [email protected] <mailto:[email protected]> > > http://mail.gnome.org/mailman/listinfo/ekiga-list > > _______________________________________________ > ekiga-list mailing list > [email protected] <mailto:[email protected]> > http://mail.gnome.org/mailman/listinfo/ekiga-list > > > ------------------------------------------------------------------------ > > _______________________________________________ > ekiga-list mailing list > [email protected] > http://mail.gnome.org/mailman/listinfo/ekiga-list -- Shawn Adams [email protected] _______________________________________________ ekiga-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/ekiga-list
