Wrong Echo cancellation delay calibration value
Fabien GUIBRETEAU via Linphone-users <[email protected]> Wed, 24 Sep 2025 11:12:31 +0000
| Newsgroups | gmane.comp.voip.linphone.user |
|---|---|
| Message-ID | <AM8P193MB085128B4F1058B6CF652EA8CC91CA@AM8P193MB0851.EURP193.PROD.OUTLOOK.COM> |
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Hello everyone,
I followed the Linphone audio tuning guide (https://wiki.linphone.org/xwiki=
/wiki/public/view/Lib/Features/Audio%20tuning/) to determine the appropriat=
e value for ec_delay. I ran the test tool (https://gitlab.linphone.org/BC/=
public/liblinphone/-/blob/master/tools/test_ecc.c) and I also ran the test =
tool inside my own project (to ensure that the API functions were using my =
project's configuration).
In both cases, the results indicated around 60ms for ec_delay, but when tes=
ting a Linphone call with "ec_delay=3D60", it doesn't work at all.
I tried to adjust the ec_delay manually and it turns out that the value tha=
t completely removes the echo is 110ms.
I can't explain why the 60ms returned by the test_ecc tool doesn't work whi=
le 110ms works well. Could you please explain to me the difference between =
the theoretical ec_delay (60) and the practical ec_delay (110) I found ? Do=
you know if there is another test or tool that could help me determine the=
correct ec_delay programmatically?
Thank you,
Have a nice day,
Fabien
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<p class=3D"MsoNormal"><span lang=3D"EN-US">Hello everyone,<o:p></o:p></spa=
n></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">I followed the Linphone audio t=
uning guide (<a href=3D"https://wiki.linphone.org/xwiki/wiki/public/view/Li=
b/Features/Audio%20tuning/">https://wiki.linphone.org/xwiki/wiki/public/vie=
w/Lib/Features/Audio%20tuning/</a>) to
determine the appropriate value for ec_delay. I ran the test tool (<=
a href=3D"https://gitlab.linphone.org/BC/public/liblinphone/-/blob/master/t=
ools/test_ecc.c">https://gitlab.linphone.org/BC/public/liblinphone/-/blob/m=
aster/tools/test_ecc.c</a>) and I also
ran the test tool inside my own project (to ensure that the API functions =
were using my project’s configuration).
<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">In both cases, the results indi=
cated around 60ms for ec_delay, but when testing a Linphone call with ̶=
0;ec_delay=3D60”, it doesn’t work at all.
<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">I tried to adjust the ec_delay =
manually and it turns out that the value that completely removes the echo i=
s 110ms.<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">I can’t explain why the 6=
0ms returned by the test_ecc tool doesn’t work while 110ms works well=
. Could you please explain to me the difference between the theoretical ec_=
delay (60) and the practical ec_delay (110) I found
? Do you know if there is another test or tool that could help me determin=
e the correct ec_delay programmatically?<o:p></o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">Thank you,<o:p></o:p></span></p=
>
<p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p>
<p class=3D"MsoNormal"><span lang=3D"EN-US">Have a nice day,<o:p></o:p></sp=
an></p>
<div>
<div>
<p style=3D"margin:.1pt;mso-line-height-alt:0pt">Fabien<o:p></o:p></p>
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