[pjsip] In-band DTMF detection

David Clark vdc1048 at tx.rr.com
Sat Aug 15 19:17:30 EDT 2009

Ok I have not done inband but I have done FFT and they are similar in 
terms of approach.  For inband dtmf check out this algorithm.

Now for how to get the audio data from the conference port source to 
the detection algorithm.  Do this.
Just a memory capture device and every time you get a packet of audio 
data call this dedection function to determine what dtmf's are
present, then you can call your on_dtmf_callback function for a 
seemless interface between inband and non-inband calls.

That is the short answer.

At 01:50 PM 8/15/2009, Archie Rosenblum wrote:
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>Does anyone have an in-band DTMF solution for pjsip?  I know this 
>question has been raised in the past and I am hoping some 
>crackerjack coder has figured it out and would like to share it with 
>the group.  I've been seeing more and more DTMF converted to in-band 
>through various voip providers and I just not savvy enough to 
>understand how to code this detection in pjsip.
>Any help is appreciated.
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