Bonbon-Chan
Posts: 15
Joined: Tue Oct 13, 2015 4:04 pm

Linphone / USB sound card / Echo cancellation

Fri Dec 11, 2015 7:17 pm

Hi,

I'm setting up a SIP Phone using Linphone (python API). It's works fine until now but I have a echo when I speak.

The microphone and the speakers are connected to the same USB sound card.
I have try with both core.echo_cancellation_enabled to False (it is sayed that it use a hardware algorithm) and True (software algorithm) but it is the same for me.

It's seems that the echo cancellation need to have a specific hardware (something like timed output/input).
How do I know if my system can support echo cancellation ?
Or may be there is something to do at the driver level ?
Anyone manage to make echo cancellation works on the PI ?

Thanks.

tim87994
Posts: 1
Joined: Sun Dec 13, 2015 6:21 am

Re: Linphone / USB sound card / Echo cancellation

Sun Dec 13, 2015 6:32 am

The fact that you are hearing echo (i.e. you hear yourself while you are speaking) means that the problem is probably on the far-end (i.e. your party to the call). Please ask your party to enable echo cancellation on his/her phone. Also, for testing purpose you can ask your party to use headsets (that in most cases prevent acoustic echo).
In general, when echo appears, there are several ways to handle the situation - they should be applied on the side that is generating the echo and not on the side that is hearing the echo:
a. Use the build-in echo cancellation (hardware or software).
b. Use headsets.
c. Use external echo cancellation software like Personal PBXMate for SIP phones.

Bonbon-Chan
Posts: 15
Joined: Tue Oct 13, 2015 4:04 pm

Re: Linphone / USB sound card / Echo cancellation

Mon Dec 14, 2015 6:25 pm

tim87994 wrote:The fact that you are hearing echo (i.e. you hear yourself while you are speaking) means that the problem is probably on the far-end (i.e. your party to the call). Please ask your party to enable echo cancellation on his/her phone. Also, for testing purpose you can ask your party to use headsets (that in most cases prevent acoustic echo).
I'm using "real" phone on the other side (fixe and GSM). So it is a problem on the PI.
tim87994 wrote: In general, when echo appears, there are several ways to handle the situation - they should be applied on the side that is generating the echo and not on the side that is hearing the echo:
a. Use the build-in echo cancellation (hardware or software).
Doesn't work for me. May be I do something wrong there. I will try to play with "ec_delay", "ec_tail_len" and "ec_frame_size" but I don't really know what I'm doing.
tim87994 wrote:b. Use headsets.
Of course it will solve the problem but I don't want to use headset. It will be the very last resort.
tim87994 wrote:c. Use external echo cancellation software like Personal PBXMate for SIP phones.
I never use one. I can take a look to it.

Thanks for the reply.

Bonbon-Chan
Posts: 15
Joined: Tue Oct 13, 2015 4:04 pm

Re: Linphone / USB sound card / Echo cancellation

Wed Dec 16, 2015 5:07 pm

Not much luck until now.

Some people speak of a echo calibration, but I found nothing on the PI (nether the software in xwindow or in command line).

I have find entry in the Java API of linphone. But nothing in the Python API.

Rahul1407
Posts: 2
Joined: Wed Jun 06, 2018 8:26 am

Re: Linphone / USB sound card / Echo cancellation

Thu Jun 07, 2018 6:36 am

Can you provide information regarding python with linphone that you achived.

brandoncheah
Posts: 31
Joined: Thu Sep 27, 2018 9:52 am

Re: Linphone / USB sound card / Echo cancellation

Wed Oct 24, 2018 3:10 am

Hi, I also have the same problem where I can hear back my own voice on my phone.

I have an external speaker and microphone connected to the RPi using a USB sound card.
What I see now is the output audio that the speaker produces is going back into the microphone beside it, therefore I'm hearing back my voice.

Is there any method to disable microphone or other software configuration required to disable echo?

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