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DTMF tone detection in live audio stream (for sapporo110)

Implement C++ classes and test application to detect DTMF tones in a continuous live audio stream using Goertzel algorithm.

The audio stream will be received in a Directshow graph and extracted using the Sample Grabber filter, we can provide all the code to build the graph and receive the audio samples if required.

Need to detect DTMF tones in the audio at various sample rates (8, 11.025, 12, 16, 22.05, 24, 32, 44.1 and 48kHz) in mono or stereo (either left/right or both).

The following features should also be implemented:

1. Detect silence between tones (so we know if a tone has been pressed twice)

2. Check for harmonics so that music can be rejected as not a DTMF tone

3. Check that the magnitude of the row and column frequency are similar

4. Check for column frequencies first then stop precessing if they aren't found (reduces CPU load)

5. 40mS tones may not be aligned with 40mS sample buffers (might be 10mS of tone in previous and 30mS of tone in next buffer), need to allow for that.

6. Must work with above sample rates (most algorithms only work at 8kHz, we need all 9 sample rates)


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I've attached some sample wav files and Directshow code to open a wav file, for testing it might be easier just to read the wav files directly as a binary file.

## Deliverables

Windows OS

Visual Studio 2008, 2010 or 2012


Can use ATL, not MFC or other large libraries.

Skills: Embedded Software, Software Architecture, VoIP, Windows Desktop

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About the Employer:
( 44 reviews ) Altona, Australia

Project ID: #2783226

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$300.05 USD in 28 days
(20 Reviews)