Speex dev - Apr 2005 - pre-processing for audio quality

We are using Speex as our major codec for voice application. We like
the Speex solution so far. Currently,
We have tried to compare voice quality between different 
public available VOIP solutions such as Skype and others.
We notice Skype use higher CPU for signal processing. Is it
because of this extra work the audio quality sounds clear?
(Sometimes, it sounds like the audio signal is not real. 
It sounds like Dolby-effect has been added.)

We are wondering whether we need to preprocess the audio 
signal before it gets into Speex codec. 

    Any comment is appreciated!! Thanks in advance.

kc
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I've never tried Skype, but I think it can be made to use wideband (16
kHz) encoding, which would explain why you say it sounds clearer. You
can do the same with Speex too. As for the preprocessor, what it could
give you is to remove the background noise and/or adjust the gain.

	Jean-Marc

Le jeudi 14 avril 2005 ? 23:08 -0700, KC Lee a ?crit :
> We are using Speex as our major codec for voice application. We like 
> the Speex solution so far. Currently,
> We have tried to compare voice quality between different 
> public available VOIP solutions such as Skype and others.
> We notice Skype use higher CPU for signal processing. Is it
> because of this extra work the audio quality sounds clear?
> (Sometimes, it sounds like the audio signal is not real. 
> It sounds like Dolby-effect has been added.)
>  
> We are wondering whether we need to preprocess the audio 
> signal before it gets into Speex codec. 
>  
>     Any comment is appreciated!! Thanks in advance.
>  
> kc
> _______________________________________________
> 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

Jean-Marc Valin <Jean-Marc.Valin@USherbrooke.ca> writes:
> You can do the same with Speex too
You can use 32kHz as well, according to the web site

Wikipedia lists 48kHz too, I wonder why,
http://en.wikipedia.org/wiki/Speex

-- 
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