[Freeswitch-users] Removing echo.

Tue Mar 19 22:34:48 MSK 2013

This has already been covered in this thread. No it will not be integrated
with FreeSWITCH. Oslec is GPL¹d and can not be integrated with FreeSWITCH
due to licensing issues. The GPL is not compatible with the MPL1.1.

On 3/19/13 12:27 PM, "Vitalie Colosov" <vetali100 at gmail.com> wrote:

> Before the thread dies I would like to add to this subject that there is an
> Open Source echo canceler exists: Oslec
> As written on their site it already works with "You-Know-Who"... :)
> Has anyone seriously considered integrating it into FreeSWITCH?
> 
> 
> 2013/3/19 Sean Devoy <sdevoy at bizfocused.com>
>> Anthony and Spencer,
>>  
>> Thanks for your responses. Anthony the megaphone analogy really worked for
>> me.  Spencer thanks for saving me the time of looking up those settings.
>>  
>> I agree cell phones frequently have huge echo.  The longer the echo delay
>> (aka higher latency) the harder it is to correct makes perfect sense as well.
>>  
>> I actually had a chance to talk to one of the users experiencing this
>> problem.  Bear in mind I usually get to talk to her boss who is looking for
>> reasons to not pay his bill.  She said they do still ³occasionally² get echo
>> but it is not too bad.  She said it is always worse when the call certain
>> people (that correlate¹s with end user device problems).  Then she mentioned
>> I was one of the ones they usually get echo with and it was happening now,
>> but not that bad!
>>  
>> Opportunity knocked, so I jumped in!  First a quick note of reference  I
>> have moderately high hearing loss and wear hearing aids.  I keep my headset
>> turned up fairly high!  I asked the user who called me to talk to herself
>> while I did some tests and tell me if the echo got better or even went away.
>> Low and Behold  mute made it go away COMPLETELY.  As much as I hate it when
>> Anthony is right, it is hard to deny it.  I tested further and each of these
>> things helped enough that she noticed:  Turning my headset speaker down on
>> the inline volume control, turning the headset speaker down at the phone,
>> turning my microphone boost down (this headset has 3 settings for microphone
>> level), muting at the phone or on the inline headset control.  All of those
>> things taken collectively say ³Listen to Anthony butthead.²
>>  
>> So, assuming the cause of the echo is beyond my control (e.g. someone else¹s
>> phone) are we just screwed or is it just cost prohibitive?  I would rather
>> reply that it would cost $5000 to fix it than say ³can¹t be helped.²
>>  
>> Suppose the user detects bad echo.  Is there anything we could do (assuming
>> they could notify FS through a programmable key or even web link, etc)? 
>> Could we drop the gain to and from the remote end?
>>  
>> I promise to let this die now.  Let me here your final thoughts.
>>  
>> Thanks again for your time and patience.
>>  
>> 
>> From: freeswitch-users-bounces at lists.freeswitch.org
>> [mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of Spencer
>> Thomason
>> Sent: Tuesday, March 19, 2013 11:40 AM
>> 
>> 
>> To: FreeSWITCH Users Help
>> Subject: Re: [Freeswitch-users] Removing echo.
>>  
>> Hi Sean,
>> 
>> We were experiencing a similar problem with these units and were able to
>> verify that it was in fact the remote end but the threshold of the echo
>> canceler seems to be too low by default.  We could hear echo and then unplug
>> the handset from the base on the other end, without muting, and the echo
>> would stop.  We found that decreasing the gain slightly all but eliminated
>> complaints.  This does reduce the level slightly but in our traces it was
>> close to on par with an analog handset.  The pertinent configuration options
>> are:
>> 
>>  
>> 
>>   <Handset_Input_Gain>-6</Handset_Input_Gain>
>>   <Headset_Input_Gain>-6</Headset_Input_Gain>
>>   <Speakerphone_Input_Gain>-6</Speakerphone_Input_Gain>
>>   <Handset_Additional_Input_Gain>0</Handset_Additional_Input_Gain>
>>   <Headset_Additional_Input_Gain>0</Headset_Additional_Input_Gain>
>>   <Speakerphone_Additional_Input_Gain>0</Speakerphone_Additional_Input_Gain>
>> 
>>  
>> 
>> Thanks,
>> 
>> Spencer
>> 
>>  
>> 
>>  
>> 
>> On Mar 19, 2013, at 7:49 AM, Anthony Minessale wrote:
>> 
>> 
>> Sean,
>> 
>>  
>> 
>> You are welcome to disagree.  Science is driven by people being unwilling to
>> accept things as they are.
>> 
>> I do have some explanations for you if you are interested.
>> 
>>  
>> 
>> Cisco and Linksys ATA both have echo cancelers in them at the point where the
>> analog data is converted to digital.  This is the ideal place for it as I
>> mentioned earlier.  So they actually are doing something about the problem
>> and that is why you do not observe one.  Getting echo while using a cell
>> phone is also very common.  The more latency and conversion of the audio data
>> you experience, the more likely you can have echo.  (iPhone is notorious) The
>> other place where its important to have echo cancellation is the point where
>> the digital data in the rtp stream is transferred into the TDM gateway
>> interfacing with the PSTN.  This is why most TDM cards like Digium and
>> Sangoma have onboard echo canceler chips.  We are not completely helpless, we
>> can do some unnatural things like decode the audio signal we are passing
>> through and try to run some echo cancellation on it but, in the conditions
>> you describe where you hear a perfect replica of what you are saying 2-5
>> seconds later only softer.  That is for sure outside the range of any
>> echo canceler.  It cannot reliably tell that this clean signal coming many
>> seconds later should be filtered out because its a replica of data that has
>> already passed by long before.  Usually in this type of issue, you are
>> actually hearing the other side hear what you said.  So you say the
>> statement, the latency takes its toll and the echo is coming back at you from
>> the far end as they are hearing it.  
>> 
>>  
>> 
>> I am open to options.  We do have some work on doing some inline audio
>> processing underway but we should not rely on them if we can possibly control
>> the surroundings better first.  If you are talking to me in the same room
>> using a megaphone and I am wearing ear plugs.  Its easier to tell you to turn
>> off the megaphone and tell me to remove the ear plugs.
>> 
>>  
>> 
>>  
>> 
>>  
>> 
>>  
>> 
>> On Mon, Mar 18, 2013 at 9:24 PM, Sean Devoy <sdevoy at bizfocused.com> wrote:
>> 
>> Hey Anthony,
>>  
>> Does that mean PBXMate is not worth investigating?
>>  
>> I have to disagree here. Placing the blame entirely on the phones at the
>> other end doesn¹t hold water for me.  I have had echo problems calling from
>> my cell phone when leaving a voice mail on FS where there is no phone at the
>> other end. So clearly there are situations where it ain¹t just the phone at
>> the other end.  It also leaves no explanation why Cisco Phones and Linksys
>> ATAs don¹t have the same problem with Commercial Venders like Vonage.  They
>> don¹t have anything different at the end of the line for echo cancellation
>> then FS does. I have also had users confirm they are still getting echo with
>> the microphone MUTED on my end.
>>  
>> Again, I love FS and I am not trying to bash anyone or any code.  I am just
>> saying there has to be more to this puzzle.  I know what a crappy speaker
>> phone¹s echo sounds like and I am not at all concerned about that. Crappy
>> speaker phones sound like crappy speaker phones no matter what. I don¹t think
>> that¹s what I am trying to track down.  These are business call where 90% are
>> using the standard handset on business quality phones.  It happens at various
>> levels, but when it is at the bad end of the spectrum (e.g. long delay and
>> loud), it does not sound like echo off of walls coming back in a microphone. 
>> It is like my input channel has been delayed, softened and looped directly
>> back to me crystal clear.  Maybe it is one of my VOIP providers¹ hardware or
>> software and is load dependent, but the problem exists outside of cheap
>> phones. And of course it is only reproducible on 3 calls in a hundred at peak
>> usage hours, making it a nightmare to track or diagnose.  But those 3 calls
>> are the ones my customers want to talk about at billing time.
>>  
>> Now, I have just thrown that all out there is hopes that 50 people will say
>> ³That absolutely never happens to me with FS² so I can look at it a different
>> way.
>>  
>> Thanks for your thoughts.
>> Sean
>>  
>> From: freeswitch-users-bounces at lists.freeswitch.org
>> [mailto:freeswitch-users-bounces at lists.freeswitch.org] On Behalf Of Anthony
>> Minessale
>> Sent: Monday, March 18, 2013 7:30 PM
>> 
>> 
>> To: FreeSWITCH Users Help
>> Subject: Re: [Freeswitch-users] Removing echo.
>> 
>>  
>>  
>> 
>> The best place for echo cancelation is in the clients as close to the mic as
>> possible.
>> 
>> Someone asked why skype and some apps are better.  It's because they have
>> echo cans in the client app.
>> 
>> Sip soft phones are basically toys unless they have some kind of advanced
>> gain and echo controls on your pc because that is where your mic is and could
>> have the vol turned up too high etc.
>> 
>>  
>> 
>> From FS perspective in the middle, we can't tell its echo or not because we
>> are just passing the data along and we're typically getting it 30-70 ms too
>> late.  
>> 
>>  
>> 
>>  
>> 
>> In general, you don't get echo when using real phones because they have
>> proper hardware and software to deal with the place where the audio is being
>> sampled and rendered.
>> 
>>  
>> 
>>  
>> 
>>  
>> 
>>  
>> 
>>  
>> 
>> On Mon, Mar 18, 2013 at 5:15 PM, Christopher Rienzo <cmrienzo at gmail.com>
>> wrote:
>> Echo cancellation is not easy.  The only open source one I've seen is GPL
>> (making it license incompatible with FreeSWITCH) and is not suitable for
>> handling echo over IP networks.  Perhaps tricks are being played using VAD to
>> only allow only one speaker at a time in the ooVoo conference?
>> 
>>  
>> 
>> On Mon, Mar 18, 2013 at 5:53 PM, Mimiko <vbvbrj at gmail.com> wrote:
>> Today we tried ooVoo conference system with theirs client using same
>> boxes and microphones - again, no echo. How this can be? Is it only
>> commercial products have echo removing function?
>> 
>> 
>> --
>> Mimiko desu.
>> 
>> _________________________________________________________________________
>> Professional FreeSWITCH Consulting Services:
>> consulting at freeswitch.org
>> http://www.freeswitchsolutions.com <http://www.freeswitchsolutions.com/>
>> 
>> 
>>  </>
>> 
>> Official FreeSWITCH Sites
>> http://www.freeswitch.org <http://www.freeswitch.org/>
>> http://wiki.freeswitch.org <http://wiki.freeswitch.org/>
>> http://www.cluecon.com <http://www.cluecon.com/>
>> 
>> FreeSWITCH-users mailing list
>> FreeSWITCH-users at lists.freeswitch.org
>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>> http://www.freeswitch.org <http://www.freeswitch.org/>
>>  
>> 
>> _________________________________________________________________________
>> Professional FreeSWITCH Consulting Services:
>> consulting at freeswitch.org
>> http://www.freeswitchsolutions.com <http://www.freeswitchsolutions.com/>
>> 
>> 
>>  </>
>> 
>> Official FreeSWITCH Sites
>> http://www.freeswitch.org <http://www.freeswitch.org/>
>> http://wiki.freeswitch.org <http://wiki.freeswitch.org/>
>> http://www.cluecon.com <http://www.cluecon.com/>
>> 
>> FreeSWITCH-users mailing list
>> FreeSWITCH-users at lists.freeswitch.org
>> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
>> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
>> http://www.freeswitch.org <http://www.freeswitch.org/>
>> 
>> 
>>  

-- 
Ken
http://www.FreeSWITCH.org
http://www.ClueCon.com
http://www.OSTAG.org
irc.freenode.net #freeswitch

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.freeswitch.org/pipermail/freeswitch-users/attachments/20130319/5da1ee9b/attachment-0001.html 