OnsetsDS

/**

    This file is part of "onsetsds".

    (c) 2011 Dan Stowell and Queen Mary University of London

    All rights reserved.

    onsetsds is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    onsetsds is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with kdpee.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "math.h"

#include "mex.h"

#include "onsetsds.h"

////////////////////////////////////////////////////////////////////////

// MATLAB ENTRY FUNCTION:

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])

{

        // implementation of: onsetsds(fftdata, odftype, medspan, srate)

        // Get the star of the show, the fft data

        const mxArray *fftdata;        

        fftdata = prhs[0];

        if(!mxIsComplex(fftdata)){

            mexErrMsgTxt("onsetsds expects a matrix of complex data (e.g. from fft()).\n");

        }

        const size_t fftframesize = mxGetM(fftdata);

        const size_t numframes    = mxGetN(fftdata);

        const double* real = mxGetPr(fftdata);

        const double* imag = mxGetPi(fftdata);

        // optional args

        int odftype = ODS_ODF_RCOMPLEX;

        if(nrhs>1){

                odftype = mxGetScalar(prhs[1]);

                if((odftype < 0) || (newodftype > 6))

                    mexErrMsgTxt("onsetsds: unrecognised ODF type.\n");

        }

        const unsigned int medspan

                          = (nrhs<3) ? 11 : (unsigned int) mxGetScalar(prhs[2]);

        const float srate = (nrhs<4) ? 44100.f : (float) mxGetScalar(prhs[3]);

        // set up the ods

        OnsetsDS ods;

        float* odsdata = (float*) malloc( onsetsds_memneeded(odftype, fftframesize, medspan) );

        onsetsds_init(&ods, odsdata, ODS_FFT_SC3_COMPLEX, odftype, fftframesize, medspan, srate);

        // This is where we'll repack an individual frame

        float* packeddata = malloc(fftframesize * sizeof(float));

        // set up the output array, size numframes

        double *results = (double*) mxCalloc(numframes, sizeof(double));

        if(!results){

            mexErrMsgTxt("onsetsds error, could not create results array (out of memory?).\n");

        }

        ////////////////////////////////////////////////////////////////////////////

        // iterate the frames, converting to expected format and onset-detecting

        size_t i;

        for(i=0; i<numframes; ++i){

                // copy the data into an array in ODS_FFT_SC3_COMPLEX format.

                // note that here we're discarding stuff above nyquist, since assuming real-valued input.

                size_t frameoffset = fftframesize * i;

                packeddata[0] = (float) real[frameoffset];

                packeddata[1] = (float) real[frameoffset + fftframesize / 2];

                size_t j;

                for(j=1; j< fftframesize/2; ++j){

                        packeddata[j+j]   = (float) real[frameoffset + j];

                        packeddata[j+j+1] = (float) imag[frameoffset + j];

                }

                bool onset = onsetsds_process(&ods, packeddata);

                results[i] = (onset ? 1.0 : 0.0);

        }        

        // Copy the results from double-array into matlab format

        mxArray *resultsM = mxCreateDoubleMatrix(1,numframes,mxREAL);

        memcpy(mxGetPr(resultsM), results, numframes * sizeof(double));

        plhs[0] = resultsM;

        // destroy the ods correctly, and any matlabby things that need to go too.

        free(ods.data);

        free(packeddata);

        mxFree(results);

}