Speex dev - Jun 2006 - Re: AEC frame size

?
hi all,
i am using the Acoustic Echo Cancellation from  "Speex 1.1.12 version"
in  my VOIP application. Is it that the  frame length to be chosen should always
be 20ms or can i have flexibility in chosing the frame lenght?
on what parameters does the frame length choise depends?
thank you all,
Shri.
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Welcome everybody.
I am new here on the list. Thank you very much for speex encoder and decoder. 
They are working great. I compile speex coded for str911 Arm processor. 
But I have a big problem with echo canceller from 1.1.12 speex package.

I create echo canceler state:
    SpeexEchoState * echo_state = speex_echo_state_init(FRAME_SIZE,
FRAME_SIZE * 5);

FRAME_SIZE is in my project 160 samples. I have 8000ksaples/s, so I must
call echo canceler every 20ms.

and later in the loop I call it:
    speex_echo_cancel(echo_state, (short *)Samples, (short
*)SamplesSpeaker, (short *)SamplesOut, NULL);

I give as the parameters to the function the data from tables now.

The problem is when I call speex_echo_cancel it does not return. It goes
into infinite loop somewhere.
I test now on the simulator.

What can cause the infinite looping ?

Please help.

Le mercredi 07 juin 2006 ? 10:03 +0000, shridhar desai a ?crit
:
>   
> hi all,
> i am using the Acoustic Echo Cancellation from  "Speex 1.1.12
version"
> in  my VOIP application. Is it that the  frame length to be chosen
> should always be 20ms or can i have flexibility in chosing the frame
> lenght?
> on what parameters does the frame length choise depends?
> thank you all,
> Shri.
20 ms is usually a good idea, but you can use shorter (I don't recommend
much longer). In any case, just try it and see if it works for you.

	Jean-Marc

> The problem is when I call speex_echo_cancel it does not return. It goes
> into infinite loop somewhere.
> I test now on the simulator.
> 
> What can cause the infinite looping ?
Can you use a debugger to see where the infinite loop is. I suspect the
problem is somewhere in your code, but in case it's in Speex, I'll find
it.

	Jean-Marc

You should try the code from Subversion before troubleshooting too much.  I 
had a problem like this which was fixed a month ago, but it only appeared on 
a 16-bit DSP.

- Jim

----- Original Message ----- 
From: "A" <ap@fom.pl>
To: <speex-dev@xiph.org>
Sent: Wednesday, June 07, 2006 5:12 PM
Subject: [Speex-dev] Echo canceller problem

> Welcome everybody.
> I am new here on the list. Thank you very much for speex encoder and 
> decoder.
> They are working great. I compile speex coded for str911 Arm processor.
> But I have a big problem with echo canceller from 1.1.12 speex package.
>
> I create echo canceler state:
>    SpeexEchoState * echo_state = speex_echo_state_init(FRAME_SIZE,
> FRAME_SIZE * 5);
>
> FRAME_SIZE is in my project 160 samples. I have 8000ksaples/s, so I must
> call echo canceler every 20ms.
>
> and later in the loop I call it:
>    speex_echo_cancel(echo_state, (short *)Samples, (short
> *)SamplesSpeaker, (short *)SamplesOut, NULL);
>
> I give as the parameters to the function the data from tables now.
>
> The problem is when I call speex_echo_cancel it does not return. It goes
> into infinite loop somewhere.
> I test now on the simulator.
>
> What can cause the infinite looping ?
>
> Please help.
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
>

Hello everybody.
I have the same problem like you. I use ARM microcontroller too.
Here is the list of all functions called by speex_echo_cancel until goes 
into infinite loop:

speex_echo_cancel()
   |
spx_fft
   |
kiss_fftr
   |
kiss_fft
   |
kiss_fft_stride
   |
kf_work

Function kf_work looks like:

static void kf_work(kiss_fft_cpx * Fout, const kiss_fft_cpx * f, const 
size_t fstride, int in_stride, int * factors, const kiss_fft_cfg st)
{
  kiss_fft_cpx * Fout_beg=Fout;
  const int p=*factors++; 		// the radix
  const int m=*factors++; 		// stage's fft length/p
  const kiss_fft_cpx * Fout_end = Fout + p*m;
  if(m==1)
  {
    do
    {
      *Fout = *f;
      f += fstride*in_stride;
    }
    while(++Fout != Fout_end );
  }
  else
  {
    do
    {
      kf_work(Fout , f, fstride*p, in_stride, factors,st);		// <---------- 
here this function calls itself and that's why goes infinite
      f += fstride*in_stride;
    }
    while( (Fout += m) != Fout_end );
  }
  ...
  ...

If anybody knows how to work around this problem please help.

Regards
Andre

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Yes! The same problem :-(

Any idea ?





At 18:55 2006-06-08 +0200, Andrzej Fien wrote:
>Hello everybody.
>I have the same problem like you. I use ARM microcontroller too.
>Here is the list of all functions called by speex_echo_cancel until goes 
>into infinite loop:
>
>speex_echo_cancel()
>   |
>spx_fft
>   |
>kiss_fftr
>   |
>kiss_fft
>   |
>kiss_fft_stride
>   |
>kf_work
>
>Function kf_work looks like:
>
>static void kf_work(kiss_fft_cpx * Fout, const kiss_fft_cpx * f, const 
>size_t fstride, int in_stride, int * factors, const kiss_fft_cfg st)
>{
>  kiss_fft_cpx * Fout_beg=Fout;
>  const int p=*factors++; 		// the radix
>  const int m=*factors++; 		// stage's fft length/p
>  const kiss_fft_cpx * Fout_end = Fout + p*m;
>  if(m==1)
>  {
>    do
>    {
>      *Fout = *f;
>      f += fstride*in_stride;
>    }
>    while(++Fout != Fout_end );
>  }
>  else
>  {
>    do
>    {
>      kf_work(Fout , f, fstride*p, in_stride, factors,st);		//
<----------
>here this function calls itself and that's why goes infinite
>      f += fstride*in_stride;
>    }
>    while( (Fout += m) != Fout_end );
>  }
>  ...
>  ...
>
>If anybody knows how to work around this problem please help.
>
>Regards
>Andre
>
>_________________________________________________________________
>FREE pop-up blocking with the new MSN Toolbar - get it now! 
>http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/
>
>_______________________________________________
>Speex-dev mailing list
>Speex-dev@xiph.org
>http://lists.xiph.org/mailman/listinfo/speex-dev
>
>

Jean-Marc Valin <Jean-Marc.Valin <at> USherbrooke.ca> writes:
> 
> Le mercredi 07 juin 2006 ? 10:03 +0000, shridhar desai a ?crit :
> >   
> > hi all,
> > i am using the Acoustic Echo Cancellation from  "Speex 1.1.12
version"
> > in  my VOIP application. Is it that the  frame length to be chosen
> > should always be 20ms or can i have flexibility in chosing the frame
> > lenght?
> > on what parameters does the frame length choise depends?
> > thank you all,
> > Shri.
> 
> 20 ms is usually a good idea, but you can use shorter (I don't
recommend
> much longer). In any case, just try it and see if it works for you.
> 
> 	Jean-Marc
> 
 

Hi Jean-Marc,

I am using speex-1.1.12 version AEC with the following configuration
SAMPLE RATE : 8000Hz
FRAME LENGTH: 32 , i.e. 4msec(125usec*32)
TAIL LENGTH : 256 , 32msec
I have configured AEC for ARM-920T, 200MHz

Here are my observations
[a] AEC CPU usage 50%
[b] Still 10%trace of echo is still present
NOTE: I am not using preprocessor as my cpu usage goes upto 99%

What should i do to increase the efficiency of AEC

Thanks in advance
Ranjan Srivastava