Function detectBeats

plugins/python-module/BTrackPythonModule.cpp:10–54

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static PyObject* detectBeats (PyObject* dummy, PyObject* args)
{
    PyObject* inputObject = nullptr;
    
    if (! PyArg_ParseTuple (args, "O", &inputObject))
        return nullptr;
    
    PyArrayObject* inputArray = (PyArrayObject*) PyArray_FROM_OTF (inputObject, NPY_DOUBLE, NPY_ARRAY_IN_ARRAY);

    if (! inputArray)
        return nullptr;
        
    const double* audioSampleArray = static_cast<double*> (PyArray_DATA (inputArray));
    long signalLength = PyArray_Size ((PyObject*)inputArray);
    constexpr int hopSize = 512;
    constexpr int frameSize = 1024;
    constexpr int sampleRate = 44100;
    int numFrames = signalLength / hopSize;
    
    std::vector<double> buffer (hopSize); // buffer to hold one hopsize worth of audio samples
    
    BTrack b (hopSize, frameSize);

    std::vector<double> beats;
    beats.reserve (numFrames);
	
	for (int i = 0; i < numFrames; i++)
	{
        std::copy_n (audioSampleArray + (i * hopSize), hopSize, buffer.begin());
		
        b.processAudioFrame (buffer.data()); // process the current audio frame
        
        // if a beat is currently scheduled, store the time
		if (b.beatDueInCurrentFrame())
            beats.push_back (BTrack::getBeatTimeInSeconds (i, hopSize, sampleRate));
	}
        
    npy_intp dims = static_cast<npy_intp> (beats.size());
    PyObject* outputArray = PyArray_SimpleNew (1, &dims, NPY_DOUBLE);
    double* out = static_cast<double*> (PyArray_DATA ((PyArrayObject*)outputArray));
    std::copy (beats.begin(), beats.end(), out);
    
    Py_DECREF (inputArray);
    return outputArray;
}

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static PyObject* calculateOnsetDetectionFunction (PyObject* dummy, PyObject* args)