[speex-dev] speex preprocess redux
tharper at sightspeed.com
Mon May 17 16:03:59 PDT 2004
The main problem I am having with the system is clipping off the start
of someone's speech when they first start talking- the ends of the sentences
seem to be handled properly. I am wondering whether this is the fault of the
audio playback system or whether this is a speex issue-
I also get the musical artifacts problem with the denoiser. This seems to
be more of a problem on open air mics/speaker combinations. However,
this and the issues you pointed out are a minor deal in comparison with the
<p><p>At 03:40 PM 5/17/2004, Steve Kann wrote:
>Tom Harper wrote:
>>Hi All & Jean Marc,
>>Once again I find myself delving into the pre-processing code to fiddle
>>with the VAD, AGC and denoising code.
>>Where i am at is that I have implemented all of Steve Kann's mods, and
>>they are 90% of the way there in terms of working, except that I am still
>>having issues denoising open air mics. But that is tangential to my
>>I was wondering what the following function is supposed to be used for:
>>I couldn't find anywhere in the code that references it- it appears to update
>>the noise estimate without denoising anything- ? If so, does this need to
>>be called for AGC to work, or?
>Beats me :)
>I've found the denoiser to work very well on open-air microphones.
>One thing I've found in using the preprocessor that I need to find a
>solution for is that sometimes the denoiser is incorrectly detecting
>speech as noise. This happens when a speaker speaks for a while, and the
>denoiser tries to remove their intonation (i.e. the sound of their
>voicebox; the vowels). The result is that towards the ends of sentences,
>their voice gets "thinned" out.
>I'd like to find out how to "slow down" the rate of adaptation within the
>denoiser to make this less likely to happen. I assume that the tradeoff
>is that it will adapt more slowly to changing noise patterns (or initial
>noise). I'm just not sure where to do that; maybe if I had the "Cohen
>Paper" it would help :)
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Tom Harper - tharper at sightspeed.com
Lead Software Engineer
SightSpeed - A Roda Group Affiliated Company
918 Parker St, Suite A14
Berkeley, CA 94710
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