[Freeswitch-users] Better results from mod_vmd

Wed Aug 19 09:41:16 PDT 2009

On Wed, Aug 19, 2009 at 1:43 AM, Matthew Fong <mattdfong at gmail.com> wrote:

> Hi Eric,
> Thanks for these recommendations.
>
> for vmd-not-panasonic-home-ans.wav changing MAX_FREQ to 1450 WORKED!
>
> but I'm still having problems picking out the ~750Hz beep of sprint,
> tmobile, and verizon. I tried first cutting POINTS and VALID in half, then
> in half again, while also reducing MIN_AMPL in half but still no luck. I
> assumed from the descriptions of each, that reducing the numbers would make
> the algorithm less picky at finding a beep. Is this correct?
>
> Any other recommendations on picking up these ~750Hz beeps? Thanks again
> for the help.
>

How close are they to 750Hz? If they're not more than say +/- 16Hz then the
tone_detect app *should* be able to detect them. At the very least I would
try it. See if tone_detect can detect those beeps. While it may not be the
most elegant solution, having mod_vmd looking for one set of tones and
tone_detect looking for the 750Hz tones might actually get the job done, at
least until you and Eric can get together to see what's happening on the
750's.

-MC

>
> --matt
>
> On Mon, Aug 17, 2009 at 2:15 PM, Eric des Courtis <
> eric.des.courtis at gmail.com> wrote:
>
>> Matt,
>>
>> Okay the good news is vmd should be able to handle these cases. The
>> bad news is for whatever reason they are not getting detected at the
>> moment.
>>
>> vmd-not-panasonic-home-ans.wav is a sine at ~1400Hz you can change
>> MAX_FREQ to 1450 and play with MIN_AMPL  if that still doesn't help.
>
>
>> The following seem to use the same beep:
>>
>> vmd-not-tmobile.wav is a sine at ~750Hz but has a bit of noise
>> vmd-not-sprint.wav is a sine at ~750Hz but has a bit of noise
>> vmd-not-sprint.wav is a sine at ~750Hz but has a bit of noise
>>
>> You can try to play with these values:
>>
>> POINTS 32
>> VALID 22
>> MAX_CHIRP 22
>>
>> If that doesn't work let me know I will try to improve the algorithm
>> to detect the providers.
>>
>> Cheers!
>>
>> Eric des Courtis
>>
>>
>>
>> On Mon, Aug 17, 2009 at 1:52 PM, Matthew Fong<mattdfong at gmail.com> wrote:
>> > Hi Eric,
>> > Thanks for the response. I had tried emailing you @brenbria.com and the
>> > email had bounced, thanks for responding to my mail.
>> > If you'd be interested I .zipped up my sample voicemail beeps
>> > at http://bandcon.hellohunter.com/vmd_wav.zip
>> > I'm relatively new to telephony, but can you point me in the right
>> direction
>> > for figuring out if the beeps are sinewaves. About as far as I've come
>> with
>> > audio is being able to open the .wav files in audacity. Any website
>> >  recommendations I can read? Thanks so much.
>> > --matt
>> >
>> > On Mon, Aug 17, 2009 at 10:29 AM, Eric des Courtis
>> > <eric.des.courtis at gmail.com> wrote:
>> >>
>> >> Matt,
>> >>
>> >> You must first capture the audio beeps and verify that they are sine
>> >> waves. If not, simply tweaking the algorithm will not give you better
>> >> results.
>> >>
>> >> It might be possible to use FFT and I would be happy to help you
>> >> implement such a solution but keep in mind FFT is very very demanding
>> >> on the hardware. Ideally what you want to find out is what functions
>> >> was use to generate the beep in the first place so that it can be
>> >> detected. Is it two sines waves like in DTMF? Or something more
>> >> complex?
>> >>
>> >> Anyway my email is eric.des.courtis at benbria.ca.
>> >>
>> >> Cheers.
>> >>
>> >> Eric des Courtis
>> >>
>> >> On Mon, Aug 17, 2009 at 12:26 AM, Matthew Fong<mattdfong at gmail.com>
>> wrote:
>> >> > I tried emailed Eric, seeking advice on this, but his email (the one
>> in
>> >> > the
>> >> > source code) is bouncing email (invalid user), so thought I would ask
>> >> > here
>> >> > instead. If anyone has eric's new email address, I'd be interesting
>> in
>> >> > it.
>> >> >
>> >> > I did some tests with mod_vmd this afternoon, but I'm only finding
>> about
>> >> > 33%
>> >> > of the voice mail beeps and did have 1 false-positive in my test of
>> >> > 7 voice
>> >> > mail machines. I've recorded the audio of the session in .wav files
>> that
>> >> > were both successful and not, as a comparison. I can upload the .wav
>> >> > files
>> >> > if they would be useful.
>> >> > mod_vmd works great for voicemails of Skype Users, and kall8.com,
>> but
>> >> > has
>> >> > issues dealing with mobile phone carriers.
>> >> > sprint - not successful
>> >> > tmobile - not successful
>> >> > verizon - not successful
>> >> > panasonic home answering machine system - not successful
>> >> > kall8 - SUCCESS
>> >> > skype - SUCCESS
>> >> > I'm wondering if you can recommend a simple fix, like changing some
>> of
>> >> > the
>> >> > constants like MAX_FREQ, or MIN_TIME at the top of the mod_vmd.c
>> source
>> >> > file, or if better success requires more complex analysis.  Do you
>> have
>> >> > any
>> >> > recommendations on how this might be done? Listening to the .wav's
>> >> > its apparent the beeps are not as loud for the mobile phone carriers
>> as
>> >> > they
>> >> > are with skype and kall8. Any guidance would be greatly appreciated.
>> >> > --matt
>> >> > hello hunter
>> >> > http://www.hellohunter.com
>> >> > voice broadcasting & hosted dialer
>> >> > _______________________________________________
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>> >
>>
>
>
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