Displaying 20 results from an estimated 2000 matches similar to: "AEC for PCM codec"
2011 May 26
2
AEC learning behaviour
> Yes, you are not forced to reset the AEC between calls at all, if you
> can assume the actual echo path (physical environment) will not change
> much, you can keep the instance and continue using it for the next call.
>
> Also what we did was keep the AEC running between calls - but we had a
> rather high-duty system with sounds and signals played between calls, so
> the AEC
2011 May 25
2
AEC learning behaviour
On Tue, 2011-05-24 at 11:09 -0400, Jean-Marc Valin wrote:
> The fact that the AEC takes a few seconds to converge is normal. The
Do you think there might be a way to reduce this?
> fact that it needs to completely re-converge in the middle of a call
> probably indicates that something went "wrong" in the audio
> capture/playback. For example, that could be an
2011 May 25
1
AEC learning behaviour
Perhaps you could add a warm-start to the AEC, such that the parameters
start near the correct values on all but the first use?
Stuart
On 05/25/2011 08:22 AM, Andras Kadinger wrote:
> 2011.05.25. 4:52 keltez?ssel, Arun Raghavan ?rta:
>> On Tue, 2011-05-24 at 11:09 -0400, Jean-Marc Valin wrote:
>>> The fact that the AEC takes a few seconds to converge is normal. The
>> Do
2011 May 25
1
pre-processor's residual echo suppression and AEC order
Hi,
Arun and me are working on a echo-canceler module for pulseaudio build around
speex. When using the preprocessor's echo filter, specifically in combination
with denoise and AGC, it's unclear whether these have to run before or after
the AEC.
Right now we've got one instance of speex_preprocessor doing AGC and denoise
running before the echo canceler; and a second for echo
2011 May 27
1
AEC learning behaviour
Hi,
I already implemented and posted a patch to do this serialization a few
weeks ago.
http://permalink.gmane.org/gmane.comp.audio.compression.speex.devel/6913
It is not integrated into the main git tree though.
Regards,
Simon
On 26/05/2011 21:21, Stuart O Anderson wrote:
> This is not part of the current API. It shouldn't be too hard add a
> serialization routine for
2009 Jul 06
2
AEC with different soundcards
The problem with different sound cards is that their clocks are not
usually synchronized, and therefore the clock drift adds a non-linear
factor to the audio path. The AEC can only cancel linear changes to the
audio path, and so the AEC never converges.One solution is to measure
the clock drift and resample either the input or output signal so that
they *are* synchronized, and then the AEC
2009 Aug 11
2
AEC troubleshooting
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2006 Aug 08
2
How to use aec correctly?
Hi,all
I have tested AEC on files, it works well.I have some files,one is echo
file, others are echo-added files(an origin file adding echo at different
delay,such as 20ms,40ms...120ms,140ms).AEC do wonderfully on those files
except echo added at 140ms-delay.
But ,when i use AEC in my voip project, it does feebly. Who can give me
some hints why caused this.How long can sound be picked up by
2011 Jan 03
3
Distorted output in fixed-point AEC
Hi,
I couldn't find a discussion that specifically addresses this, so here it
is.
I'm using Speex AEC in my mobile VoIP application to cancel speaker echo.
The used version is 1.2rc1 from the website, and I'm compiling with
fixed-point.
On most occasions, the AEC works very well and cancels most of the echo
(combined with the preprocessor).
On some devices, where the microphone signal
2007 Jul 20
2
Server Side AEC
Hi,
I am looking for AEC software which can be run on the server side. This means there will be a fairly constant 600ms or so gap between sending out an audio frame and getting it back with echo. Could Speex AEC be configured to handle these conditions? If so, how good can I expect it to be?
Thanks
---------------------------------
Yahoo! Mail is the world's
2006 Sep 28
2
need a help for using AEC
speex-devDear Jean-Marc Valin
I got some problems with evaluating the AEC module of speex. I wrote a test main function and compiled it with the speex lib in VC6.0, it initialized the AEC state and called the AEC main function in the same way as what was done in testecho.c. The near-end input wave file was a simple delaying and adding version of the far-end input wave, eg. y(n) =
2007 Jul 22
2
Server Side AEC
Hi Jean-Marc,
Regarding you points:
1) Is it ok if the audio is encoded (using Nelly Moser ASAO) and sent to the client and decoded when it is recevied so the AEC is always performed on raw PCM16 8KHZ ?
2) The audio is moved in 32ms (512 byte) chunks and the reading and writing to the AEC code will be done by separate threads at regular 32 ms intervals.
3) Occasionaly audio is
2009 Aug 11
2
AEC troubleshooting
I actually forgot to mention that I'm using ultra-wideband mode, but seems
like you understood that anyway. Is this true that Speex echo cancellation
only performs well in narrowband mode !?
I've been using 100 ms as the default tail length. I don't know what the
ideal tail length would be. I have tried shorter and longer tails but it
hasn't made any difference.
Does
2006 Oct 24
2
fixed point AEC
Analog Devices sponsored a fixed point version for AEC which was posted early this year, but it seems from the source code that the fft routines are still in floating point. Is the port still not complete or am I missing something? Has anyone out there ported speex AEC on RISC architecture? Please let me know.
Thanks in advance,
-Deepa
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2011 Jan 08
1
Distorted output in fixed-point AEC
Hi Jean-Marc, thanks for the response.
First, I will clarify again that floating-point solves this - so isn't that a bug in fixed-point?
Also, I understand that algorithmically the AEC won't cancel echo properly on a non-linear signal, but why completely distort the output?
If the echo just won't get cancelled it would be acceptable, but in the current state it disables the ability to
2007 Jul 22
1
Server Side AEC
The client is the adobe flash player. No install and on 98% of all desktops but we can't change it.
It works ok if people use headphones but we need to stop the howl than can build up if more than one person in a conference has mic to close to speakers.
Any ideas?
Jean-Marc Valin <jean-marc.valin@usherbrooke.ca> wrote:
> 1) Is it ok if the audio is encoded (using
2005 Dec 10
3
AEC params
Hi:
By 'no success', I mean result gets worse in terms
that, there comes in a shrill noise with high gain and
also *no* attenuation of the echo.
I am trying to validate the DC offset part. But can
you please feed some light on how does the DC offset
matter for AEC. As I have already mentioned, I tried
adding silence (from 2 ms to 10 ms) in the start of
the reference signal. This is for
2006 Sep 21
2
AEC in WB mode fixed yet ?
> Today's Topics:
>
> 1. AEC with WB mode (Jean-Christophe.Berge@etu.enseeiht.fr)
> 2. Multiple frame encode and decode (Reza Fatahillah)
> 3. cant link speex_echo.h (jesus)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 20 Sep 2006 08:46:03 +0200 (CEST)
> From:
2009 Jul 07
1
AEC with different soundcards
AFAIK, that's a common point for all AECs. But some of them
solve the problem by resampling on of the end to keep it in sync
with the other.
On Tue, Jul 7, 2009 at 5:14 PM, ggb<ggb at tid.es> wrote:
> Thank you John.
>
> On 07/06/2009 11:03 PM, John Ridges wrote:
>
> ly synchronized, and therefore the clock drift adds a non-linear
> factor to the audio path. The AEC
2007 Jun 19
2
speex AEC lighter configuration
Hello all,
I'm just new to this list.
I'm user of a voIP application which uses Speex Acoustic Echo Canceller
(so only user of speex). The only parameter it has to tune is the length
of the ec tail. I'm testing the echo canceller on an arm9 platform.
Tests made only allow me to raise the length of the tail until 250 msec
(upper the cpu power consumption is 100% and there are audio