[Speex-dev] Voice Activation Level (speex

Steve Kann stevek at stevek.com
Thu Mar 2 06:33:37 PST 2006


    The Voice Activity Detection (VAD) algorithm in the speex 
preprocessor does not work simply by detecting the energy level (volume 
or loudness) in the audio frames, but it uses a more complex algorithm 
which (a) tries to ignore background noise, and (b) tries to detect 
speech, in particular, and not just energy.

    If you need to adjust the sensitivity of this, you can use these 



which adjusts the 'probabilities' that are used to define speech and 
non-speech, for the start of speech, and to continue speech.


Lis wrote:

> Sorry.
> I forgotten the words volume or loudness.
> But it is know as microphone stroke too, i think.
> If something can tell me something about that
> procedure it would complete my pleasure.
> To bring back memories,
> i only wanted to know wheather i can change a
> variable that holds the sound intensity (loudness)
> needet to start "encoding >> sending" if the speex codec
> is in voice activation mode.
> If that isnt implementet yet it would enjoy me
> to get information about the preprocess->loudness2
> for example, or a function (if the lib contains one) that returns a 
> value whitch equals to the overall
> loudness of a frame.
> So i can do some simple interactions with users
> whitch doesnt want to yell in their microphone
> for talking something.
> Other ones got headsets that record their breathing
> and anyone can listen to.
> This is not funny the whole day...
> Greets Lis
> ----- Original Message ----- From: "Jean-Marc Valin" 
> <jean-marc.valin at usherbrooke.ca>
> To: "Lis" <lis at 1234567890qwertzuiopasdfghjklyxcvbnm.de>
> Cc: <speex-dev at xiph.org>
> Sent: Thursday, March 02, 2006 2:35 AM
> Subject: Re: [Speex-dev] Voice Activation Level (speex
>> Please define what you mean by "voice activation level".
>> Jean-Marc
>> On Thu, 2006-03-02 at 02:22 +0100, Lis wrote:
>>> I havent had found anything in the documentation about voice
>>> activation levels.
>>> Does i can change a variable to change the accuracy for activations?
>>> If not does the speex lib already implement a function for read out
>>> the
>>> sound level of a frame?
>>> Thanks for the advance.
>>> Lis (Louis Hoefler)
>>> _______________________________________________
>>> Speex-dev mailing list
>>> Speex-dev at xiph.org
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