Command line utility to detect sound

Command line utility to detect sound

[NickRob]

Hi

I would like to find a command line utility that will detect sound above a
certain volume and do something like terminate with a status or issue a
signal that can be trapped by another process. I haven't been able to find
anything, but using the words sound and detection together in google leads
inexorably to sound card detection!

Alternatively, which library/app would be the best one to start with if I
need to adapt something? I'm an experienced programmer, but not with sound.

Thanks for any help you can give me.

Nick
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Re: Command line utility to detect sound

[@ 2009-08-12 17:16 UTC (permalink / raw)]

NickRob wrote:
> Hi
> 
> I would like to find a command line utility that will detect sound above a
> certain volume and do something like terminate with a status or issue a
> signal that can be trapped by another process. I haven't been able to find
> anything, but using the words sound and detection together in google leads
> inexorably to sound card detection!
> 
> Alternatively, which library/app would be the best one to start with if I
> need to adapt something? I'm an experienced programmer, but not with sound.

check out the linux audio developers' mailing list. for your particular
application, grab the swh ladspa plugin set, check out the compressors.
they contain code for envelope followers, which will compute the energy
of a sound signal using the root-mean-square method. rip it out (it's
gpl) and add some C glue around it to tie into your shell scripts or
whatever it is you want to do.

best,

jörn

Re: Command line utility to detect sound

[Nicholas Robinson]

Hi Jörn

Thank you very much for your reply. I will follow up your suggestions.

Best Wishes

Nick

On Wed, 2009-08-12 at 19:16 +0200, Jörn Nettingsmeier wrote:
> NickRob wrote:
> > Hi
> > 
> > I would like to find a command line utility that will detect sound above a
> > certain volume and do something like terminate with a status or issue a
> > signal that can be trapped by another process. I haven't been able to find
> > anything, but using the words sound and detection together in google leads
> > inexorably to sound card detection!
> > 
> > Alternatively, which library/app would be the best one to start with if I
> > need to adapt something? I'm an experienced programmer, but not with sound.
> 
> check out the linux audio developers' mailing list. for your particular
> application, grab the swh ladspa plugin set, check out the compressors.
> they contain code for envelope followers, which will compute the energy
> of a sound signal using the root-mean-square method. rip it out (it's
> gpl) and add some C glue around it to tie into your shell scripts or
> whatever it is you want to do.
> 
> best,
> 
> jörn
> 
>