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Dialogic Support Helpweb
Dialogic® Diva® SDK
How to do voice activity detection (VAD)
Voice Activity Detection is done in the SDK by using the tone detection mechanism. To do this, your program should enable tones, using DivaReportTones() setting bEnable = true.From then on, you will receive the event DivaEventToneDetected whenever the Diva Server card detects a tone on the line. Each tone detected event comes with a parameter that tells you which kind of tone was detected on the line.
For the purposes of VAD, the Diva Server card sends a special tone indication called DivaHumanSpeech. When you receive this tone indication, you know that there is speech activity on this channel, and so you can use this to set or reset timers, or record "active talker" information, or whatever your application requires.
By using this event to reset a "silence timer" in your application you can also implement silence detection, i.e. if the silence timer ever expires then you know that no "human speech" has been detected on the line for 'n' seconds.
Note that the above description assumes a Diva Server board with DSPs is being used. For information on performing silence detection without DSPs, please see the article Silence detection on a CTI board.
