Speex dev - Jul 2005 - Questions about the denoiser

Hello, I have been working with the denoiser in the Speex
library and have a few questions.

 

Some information before I get started:

 

Speex version:               1.1.9 (as near as I could tell nothing new
in the denoiser in cvs)

Audio input:                   32bit float - 48000 sample rate (the
input starts from jackd)

 

The first thing I am finding is that I can understand the audio in a low
noise environment, but even listening with low noise I can hear what I
call an underwater sound in the background.  Kind of pops and clicks
that sound like digital water.    The second thing is that as the noise
gets more aggressive the beginnings and ends of words (or sentences if
the words run close enough together) seem to get garbled.  When there is
low noise and the person is talking the audio does sound good and is
completely understandable.

 

This all said what I am wondering from the group is if this is a normal
sound from the denoiser, or is it something in my implementation?  I can
certainly record some audio and provide code snips if necessary - just
let me know.


These are some specific things I was thinking about trying - but I
wanted to check with the group if I am missing some obvious first, or if
there is anything different I should be looking at:

 

1.	Should I try to use something like libsamplerate and get the
samplerate down to 8000?  
2.	Is there a way to tell the denoiser to be a little less
aggressive?  Other tuning hints in the code?

 

 

Thanks!

 

-James

 

 

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Hi,

First, the decoder is tuned for 20 ms frames, but should work for all
sampling rates. It's possible to make it less agressive, but I haven't
documented that yet.

	Jean-Marc

Le mercredi 13 juillet 2005 ? 09:51 -0500, James Van Vleet a ?crit
:
>             Hello, I have been working with the denoiser in the Speex
> library and have a few questions.
> 
>  
> 
> Some information before I get started:
> 
>  
> 
> Speex version:               1.1.9 (as near as I could tell nothing
> new in the denoiser in cvs)
> 
> Audio input:                   32bit float ? 48000 sample rate (the
> input starts from jackd)
> 
>  
> 
> The first thing I am finding is that I can understand the audio in a
> low noise environment, but even listening with low noise I can hear
> what I call an underwater sound in the background.  Kind of pops and
> clicks that sound like digital water.    The second thing is that as
> the noise gets more aggressive the beginnings and ends of words (or
> sentences if the words run close enough together) seem to get garbled.
> When there is low noise and the person is talking the audio does sound
> good and is completely understandable.
> 
>  
> 
> This all said what I am wondering from the group is if this is a
> normal sound from the denoiser, or is it something in my
> implementation?  I can certainly record some audio and provide code
> snips if necessary ? just let me know.
> 
> 
> These are some specific things I was thinking about trying ? but I
> wanted to check with the group if I am missing some obvious first, or
> if there is anything different I should be looking at:
> 
>  
> 
>      1. Should I try to use something like libsamplerate and get the
>         samplerate down to 8000?  
>      2. Is there a way to tell the denoiser to be a little less
>         aggressive?  Other tuning hints in the code?
> 
>  
> 
>  
> 
> Thanks!
> 
>  
> 
> -James
> 
>  
> 
>  
> 
> 
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
-- 
Jean-Marc Valin <Jean-Marc.Valin@USherbrooke.ca>
Universit? de Sherbrooke