2008-11-26 05:18:27     Linphone and Speex Echo Cancellation

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2008-11-26 05:18:27     Linphone and Speex Echo Cancellation

Samuel Ayet (SPAIN)

Message: 65839   


Hi all,


I'm using linphone running on my uClinux-2008R1.5 (@ STAMP-537) with the AD1836L daughter board. Our system comunicates a hands free VoIP phone with other VoIP phone based on a headphones, so we need to cancell the echo in the hands free VoIP phone. I have set the codec to speex@8kHz to comuniocate between the blackfin (with linphone) and my PC (also linphone). Blackfin has the Hands-Free kit and PC have the headphones, so I heard the echo when I speak from my PC.


Using linphone seems to be easy, just in '.linphonerc' writting 'echocancellation=1' and tunning the 'filter_length' and 'framesize' from 'speexec.c' located in the mediastreamer2/src folder as the speex documentation tells you.


I don't know if I have mistaked any step because the echo cancellation doesn't work, in fact, I heard the same echo with 'echocancellation=0' so I think somethink is not working.


Also I have changed the filter_length because maybe the echo arrives too late to filter it, but it still without working...


Anybody knows if I have to activate the echo supression in other file? Any ideas? Ani experience with linphone's echo cancellation?




Thank you!




2008-11-26 22:13:02     Re: Linphone and Speex Echo Cancellation

Cliff Cai (CHINA)

Message: 65876   


There is a tool "echo_diagnostic" to diagnose it,refer to "6.2.1 Troubleshooting" in http://www.speex.org/docs/manual/speex-manual.pdf.