asterisk users - Oct 2003 - Voice detection

Does anyone know if there's public voice detection algorithms available? 
I've
scoured the net for the last hour or so, and I can't come up with anything 
except a few proprietary or embedded solutions.

I know dsp.c uses goertzel algorithms for DTMF detection, but how does one 
detect voice?

I dunno, maybe detecting voice isn't the way to go.  I want to begin
playback of
a file after a phone/answering machine has answered.

Suggestions?

Brad Waite

Hi Brad,

If you want to detect that a sound is voice, rather than something else, 
it isn't easy. There is information around on the Internet about 
methods, but I have never tried them and don't know how well they work. 
Unless you have some understanding of DSP I wouldn't bother trying. On 
the other hand, if you do have some DSP expertise it might be a fun 
thing to try.

Regards,
Steve

Brad Waite wrote:
> Does anyone know if there's public voice detection algorithms 
> available?  I've scoured the net for the last hour or so, and I
can't
> come up with anything except a few proprietary or embedded solutions.
>
> I know dsp.c uses goertzel algorithms for DTMF detection, but how does 
> one detect voice?
>
> I dunno, maybe detecting voice isn't the way to go.  I want to begin 
> playback of a file after a phone/answering machine has answered.

>Yes, there's lots of voice detection software that exists - but not much
>free software.  Last year, I had to pay an audio software engineer to
>develop similar code 
Scott, dont suppose that code could be disclaimed ?? :)