Audio Problems with default AGC enabled and acoustic feedback

[peerdev]

We use the video function of 3cx a lot to hold meetings with external people.

Unfortunately, the problem is that you can't hold conferences without a headset. If a member only uses the speakers, there is acoustic feedback when they speak. This means that it is not even possible to use it without headphones.
This issue does not exist with other video conferencing tools.


It does make a difference if you deactivate AGC (always activated by default). However, this is not a solution, as it is always activated for external participants and they must be made immediately aware that it should be deactivated. It would also be nice to manage AGC globally and not have it happen on the client side.

 

[Emanuele Bizzarri]

Hi,
the flag to avoid echo is "Echo cancellation", not AGC (Automatic Gain Control). It must be activated on the side using the speakers. And yes, all these flags are activated by default to try to do the best configuration for everyone.

If the echo is not cancelled, when you talk and the other user has speakers (and echo cancellation disabled), your voice exits from his speakers and re-enter on his mic, so you hear your voice feedback.
Is that the case you are trying to solve?

Because each user can have a different conference setup (devices, meeting room, etc) these kind of settings can not be set globally; e.g. if you have speakers and not headset you must enable echo cancellation, otherwise other users will hear their voices feedback.

The echo cancellation feature is implemented directly by the browser vendors and from the user interface it can be only enabled/disabled. Which browser are you using?

 

[peerdev]

If the echo is not cancelled, when you talk and the other user has speakers (and echo cancellation disabled), your voice exits from his speakers and re-enter on his mic, so you hear you voice feddback.
Is that the case you are trying to solve?

Exactly! When one member uses speakers and another is speaking, the microphone of the corresponding user is activated - resulting in the previously mentioned feedback.

Which browser are you using?

In that case, we tried Firefox. But the mentioned problem only happens with 3cx. With other video conferencing tools, this problem does not even exist.

 

[Emanuele Bizzarri]

Hi,
with the help of peerdev we discovered that using firefox on linux the echo cancellation didn't work correctly.
The echo cancellation configuration was set correctly, but it is not respected by firefox.

After further more investigation we realized that the issue is related to the usage of another web audio api we use for getting the audio level indicator of the mic.

For some reason using this api on firefox on linux breaks the internal echo cancellation processor of the browser.
The only solution we found is to disable the audio level indicator in this particular case.

This problem affect only firefox on linux, chrome is fine and firefox on other oses is fine too.

 

[beurle]

Is this something that a firefox user can do?
"The only solution we found is to disable the audio level indicator in this particular case"

 

[Emanuele Bizzarri]

Hi,
it is implemented in the product.
Using the 3cx video conference with firefox on linux is detected automatically and the audio level indicator in the ui is disabled (you will not see audio indicator when you are talking).
In this way the echo cancellation works fine on firefox.

 

[beurle]

When I join a video call with Firefox on Ubuntu others on the call complain that they get an echo (themselves). It all sounds fine to me. This does not happen using chromium.

Any suggestions?

 

[Emanuele Bizzarri]

Then it means that Firefox on Ubuntu restarted to have problems on this part also with the workaround we implemented for the problem reported by peerdev.
We need to re-check if this problem restarted to happen and if it is possible to fix it.
@peerdev did you notice a regression here using firefox?