I changed /*! Minimum time for a beep. */ #define MIN_TIME 8000 to 6500 and it seemed to work, but I'm not sure how many false positives I will get in a real-world environment. at 4000 it fired the event like 5 times in a session, but 6500 only once. Do you think I should expect a lot of false positives after changing this value?
--matt http://www.hellohunter.com On Thu, Aug 20, 2009 at 4:54 PM, Eric des Courtis < [email protected]> wrote: > Matt, > > As is mod_vmd will not detect tones shorter then 138ms. However I > could get that value down to ~30ms at best by making a few > modifications to the algorithm. > > Cheers. > > Eric des Courtis > > > On Thu, Aug 20, 2009 at 7:51 PM, Eric des > Courtis<[email protected]> wrote: > > Matt, > > > > For your information the tones you gave me are exactly 738Hz. If you > > want to try that tone detection thing. > > > > Cheers. > > > > Eric des Courtis > > > > On Thu, Aug 20, 2009 at 2:20 PM, Michael Collins<[email protected]> > wrote: > >> > >> > >> On Thu, Aug 20, 2009 at 11:06 AM, Steve Underwood <[email protected]> > >> wrote: > >>> > >>> On 08/20/2009 05:22 AM, Michael Collins wrote: > >>> > > >>> > There is no noise on those 3 beeps. In fact, for something that's > >>> > been > >>> > through ulaw/alaw compression those beeps are very clean. They > are > >>> > quite > >>> > short, though. > >>> > > >>> > > >>> > Heck yeah they're short! Steve, in your experience is there a > >>> > practical way to detect a beep that short without chewing up system > >>> > resources or having lots of false positives? > >>> > -MC > >>> > > >>> The tone samples I just looked at are about 130ms long. The problem is > >>> the detector is trying to be a very open ended detector of anything > >>> narrowband enough to be a single tone, and of any duration beyond some > >>> small minimum. Its difficult to make such a thing voice immune unless > >>> you can also count on a very large signal to noise ratio. With a > digital > >>> trunk you can probably rely on a large SNR, but what happens when > people > >>> use analogue lines? There is a reason why DTMF detectors try hard to > >>> work down to about 10dB SNR. :-) > >>> > >>> Steve > >> > >> Thanks for the lesson uncle Steve! I'm guessing that the OP will need a > new > >> strategy. Possibly waiting for silence? Not sure what's the best way to > go > >> but I'm interested in hearing if someone has a solution. > >> > >> -MC > >> > >> > >> > >> _______________________________________________ > >> FreeSWITCH-users mailing list > >> [email protected] > >> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users > >> UNSUBSCRIBE: > http://lists.freeswitch.org/mailman/options/freeswitch-users > >> http://www.freeswitch.org > >> > >> > > > > _______________________________________________ > FreeSWITCH-users mailing list > [email protected] > http://lists.freeswitch.org/mailman/listinfo/freeswitch-users > UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users > http://www.freeswitch.org >
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