Audio processing using goertzel algorithm


I'm building a voip application. Most of it works, but I'm missing facilities for detection of tones e.g dtmf or voicemail beeps. Normally a dsp should do the job, but the telephony system used has no dsp's onboard. The Goertzel algorithm can be used to implement the logic needed.

The application has to be a dll which takes an audio buffer (alaw 8khz mono, without header (raw)), this buffer is populated by some third party software. Other arguments are : frequency(s) to detect and a time indicator (how long on a tone has to occur e.g. 100ms). When the specified tones have been detected a callback has to be done indicating which tones have been found.

The application should be robust and fast. It should be able to handle 750 concurrent calls if needed on a 3ghz dual core system with 2gb of ram. For now it will handle 4 lines, as a proof of concept.

Any suggestions appreciated.

Delivery of both a dll and the source code preferably in a ms visual studio project.

With best regards


Taidot: C-ohjelmointi

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Tietoa työnantajasta:
( 1 arvostelu ) woudenberg, Netherlands

Projektin tunnus: #520536

Myönnetty käyttäjälle:


Please check PMB.

$180 USD 7 päivässä
(4 Arvostelua)

5 freelanceria on tarjonnut keskimäärin %project_bid_stats_avg_sub_26% %project_currencyDetails_sign_sub_27% tähän työhön


Hi, Please take a look at PMB. Best regards

$199 USD 7 päivässä
(1 arvostelu)

experienced professionals

$190 USD 45 päivässä
(0 arvostelua)

did goertzel in the past in very noisy environment, know how to make it robust.

$3000 USD 6 päivässä
(0 arvostelua)

A DLL with Alaw/Goerzel? I'm ready.

$70 USD 3 päivässä
(0 arvostelua)