[Freeswitch-users] Need Less CPU Intensive Way to Detect Voicemail and Answering Machines

[David Stein]

Hello.

I need to detect answering machine beeps on 1,000+ channels 
simultaneously.  Unfortunately, this is a real requirement, not a 
pseudo-requirement that can be engineered away.  This is for a mass 
emergency notification system for government, K-12, and higher education.

In the past, I have done this with proprietary hardware (Dialogic and 
Aculab), which handles this sort of thing without overloading the host 
CPU, as the hardware's DSPs handle the detections.  I want to see if I 
can do the same thing with FreeSWITCH.

Alas, I find the following warning in the wiki page for mod_avmd:

    AVMD (and VMD) are both very CPU intensive. You need to be aware of
    this fact when using it. It will drastically reduce your call
    capacity if you do not manage it correctly. On the other hand it is
    a very useful tool, and if managed properly will be a great aid for
    calls needing to do Voice Mail Detection.

         Eric states, "You can expect about ~50 simultaneous instances
    on an Intel i7 920 CPU."

So, it sounds like VMD and AVMD won't work for what I need to do.  I 
also don't think that the tone_detect application will work, as this 
requires specific frequencies (as opposed to ranges of frequencies), and 
answering machines and voicemail come with beeps at all sorts of 
frequencies.

Does anyone know anything, either free or commercial, that I can use 
with FreeSWITCH to do this many simultaneous detections?  I know of 
commercial software-only platforms (e.g., Aculab's  Prosody S) that 
claim to be able to this, so it seems like it should be possible.

Thanks in advance,
David Stein

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