[Freeswitch-users] Better results from mod_vmd

Matthew Fong mattdfong at gmail.com
Wed Aug 19 11:50:34 PDT 2009


Can anyone recommend a tool to analyze the wave files to see what's causing
the sine wav not to be detected? I have them zipped at
http://bandcon.hellohunter.com/vmd_wav.zip
<http://bandcon.hellohunter.com/vmd_wav.zip>I was trying to use audacity,
but not sure how to tell the exact frequency.

sorry if this was a double post...

On Wed, Aug 19, 2009 at 10:26 AM, Michael Jerris <mike at jerris.com> wrote:

> my bet is if mod_vmd is not getting them that they are not going to work
> with tone detect either.  Someone needs to look at the tone and see what
> frequencies are really involved and if they change throughout the beep.
> Mike
>
> On Aug 19, 2009, at 12:41 PM, Michael Collins wrote:
>
>
>
> 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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