OnsetsDS

mex                    -I../src  onsetsds.c ../src/onsetsds.c

/**

    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);

//		printf("%i ", onset);

//		printf("[%i] %i", i, onset);

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

//		printf("[%i] %g", i, results[i]);

	}	

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

//	mwSize *dims = (mwSize*) mxCalloc(2, sizeof(mwSize));

//	dims[0] = 1;

//	dims[1] = numframes;

//	mxArray *resultsM = mxCreateNumericArray(2, dims, mxINT8_CLASS, mxREAL);

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

//	mxSetPr(resultsM, results);

	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(dims);

	mxFree(results);

	// *resultsM ? no I think that lives on in matlabworld

}

function onsets = onsetsds(fftdata, odftype, medspan, srate)

% function onsets = onsetsds(fftdata)

% function onsets = onsetsds(fftdata, odftype)

% function onsets = onsetsds(fftdata, odftype, medspan)

% function onsets = onsetsds(fftdata, odftype, medspan, srate)

%

% Musical onset detector using adaptive whitening 

%     -- see http://onsetsds.sourceforge.net/

%

%  "fftdata": a matrix of FFT frames (1 per column) derived from an audio 

%             file. The common case (used for testing the code) is 44.1 kHz 

%             audio with 50% overlap and Hann windowing.

%

%  "odftype": integer specifying onset detection function to use:

%              0 'power', 

%              1 'magsum', 

%              2 'complex',

%              3 'rcomplex',  <-- default

%              4 'phase', 

%              5 'wphase', 

%              6 'mkl'.

%  "medspan": length of median-filter in frames, default is 11.

%  "srate": sampling rate of audio, default is 44100.

%

% For more info see D. Stowell and M. D. Plumbley, 

%         "Adaptive whitening for improved real-time audio onset detection", 

%         Proceedings of the International Computer Music Conference (ICMC'07), 

%         Copenhagen, Denmark, August 2007.

%

%   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 2 of the License, or

%   (at your option) any later version.