annotate dsp/mfcc/MFCC.cpp @ 321:f1e6be2de9a5

A threshold (delta) is added in the peak picking parameters structure (PPickParams). It is used as an offset when computing the smoothed detection function. A constructor for the structure PPickParams is also added to set the parameters to 0 when a structure instance is created. Hence programmes using the peak picking parameter structure and which do not set the delta parameter (e.g. QM Vamp note onset detector) won't be affected by the modifications.

Functions modified:
- dsp/onsets/PeakPicking.cpp
- dsp/onsets/PeakPicking.h
- dsp/signalconditioning/DFProcess.cpp
- dsp/signalconditioning/DFProcess.h

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    QM DSP Library

    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2005 Nicolas Chetry, copyright 2008 QMUL.

    This program 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.  See the file
    COPYING included with this distribution for more information.
*/

#include <cmath>
#include <cstdlib>
#include <cstring>

#include "MFCC.h"
#include "dsp/transforms/FFT.h"
#include "base/Window.h"

MFCC::MFCC(MFCCConfig config)
{
    int i,j;

    /* Calculate at startup */
    double *freqs, *lower, *center, *upper, *triangleHeight, *fftFreqs;
  
    lowestFrequency   = 66.6666666;
    linearFilters     = 13;
    linearSpacing     = 66.66666666;
    logFilters        = 27;
    logSpacing        = 1.0711703;
  
    /* FFT and analysis window sizes */
    fftSize           = config.fftsize;
    fft               = new FFTReal(fftSize);

    totalFilters      = linearFilters + logFilters;
    logPower          = config.logpower;
  
    samplingRate      = config.FS;
  
    /* The number of cepstral componenents */
    nceps             = config.nceps;

    /* Set if user want C0 */
    WANT_C0           = (config.want_c0 ? 1 : 0);
  
    /* Allocate space for feature vector */
    if (WANT_C0 == 1) {
        ceps              = (double*)calloc(nceps+1, sizeof(double));
    } else {
        ceps              = (double*)calloc(nceps, sizeof(double));
    }
 
    /* Allocate space for local vectors */
    mfccDCTMatrix     = (double**)calloc(nceps+1, sizeof(double*));
    for (i = 0; i < nceps+1; i++) {
        mfccDCTMatrix[i]= (double*)calloc(totalFilters, sizeof(double)); 
    }

    mfccFilterWeights = (double**)calloc(totalFilters, sizeof(double*));
    for (i = 0; i < totalFilters; i++) {
        mfccFilterWeights[i] = (double*)calloc(fftSize, sizeof(double)); 
    }
    
    freqs  = (double*)calloc(totalFilters+2,sizeof(double));
    
    lower  = (double*)calloc(totalFilters,sizeof(double));
    center = (double*)calloc(totalFilters,sizeof(double));
    upper  = (double*)calloc(totalFilters,sizeof(double));
    
    triangleHeight = (double*)calloc(totalFilters,sizeof(double));
    fftFreqs       = (double*)calloc(fftSize,sizeof(double));
  
    for (i = 0; i < linearFilters; i++) {
        freqs[i] = lowestFrequency + ((double)i) * linearSpacing;
    }
  
    for (i = linearFilters; i < totalFilters+2; i++) {
        freqs[i] = freqs[linearFilters-1] * 
            pow(logSpacing, (double)(i-linearFilters+1));
    }
  
    /* Define lower, center and upper */
    memcpy(lower,  freqs,totalFilters*sizeof(double));
    memcpy(center, &freqs[1],totalFilters*sizeof(double));
    memcpy(upper,  &freqs[2],totalFilters*sizeof(double));
    
    for (i=0;i<totalFilters;i++){
        triangleHeight[i] = 2./(upper[i]-lower[i]);
    }
  
    for (i=0;i<fftSize;i++){
        fftFreqs[i] = ((double) i / ((double) fftSize ) * 
                       (double) samplingRate);
    }

    /* Build now the mccFilterWeight matrix */
    for (i=0;i<totalFilters;i++){

        for (j=0;j<fftSize;j++) {
      
            if ((fftFreqs[j] > lower[i]) && (fftFreqs[j] <= center[i])) {
          
                mfccFilterWeights[i][j] = triangleHeight[i] * 
                    (fftFreqs[j]-lower[i]) / (center[i]-lower[i]); 
          
            }
            else
            {
                mfccFilterWeights[i][j] = 0.0;
            }

            if ((fftFreqs[j]>center[i]) && (fftFreqs[j]<upper[i])) {

                mfccFilterWeights[i][j] = mfccFilterWeights[i][j]
                    + triangleHeight[i] * (upper[i]-fftFreqs[j]) 
                    / (upper[i]-center[i]);
            }
            else
            {
                mfccFilterWeights[i][j] = mfccFilterWeights[i][j] + 0.0;
            }
        }

    }

    /*
     * We calculate now mfccDCT matrix 
     * NB: +1 because of the DC component
     */

    const double pi = 3.14159265358979323846264338327950288;
  
    for (i = 0; i < nceps+1; i++) {
        for (j = 0; j < totalFilters; j++) {
            mfccDCTMatrix[i][j] = (1./sqrt((double) totalFilters / 2.))  
                * cos((double) i * ((double) j + 0.5) / (double) totalFilters * pi);
        }
    }

    for (j = 0; j < totalFilters; j++){
        mfccDCTMatrix[0][j] = (sqrt(2.)/2.) * mfccDCTMatrix[0][j];
    }
   
    /* The analysis window */
    window      = new Window<double>(config.window, fftSize);

    /* Allocate memory for the FFT */
    realOut     = (double*)calloc(fftSize, sizeof(double));
    imagOut     = (double*)calloc(fftSize, sizeof(double));

    earMag      = (double*)calloc(totalFilters, sizeof(double));
    fftMag      = (double*)calloc(fftSize/2, sizeof(double));
  
    free(freqs);
    free(lower);
    free(center);
    free(upper);
    free(triangleHeight);
    free(fftFreqs);
}

MFCC::~MFCC()
{
    int i;
  
    /* Free the structure */
    for (i = 0; i < nceps+1; i++) {
        free(mfccDCTMatrix[i]);
    }
    free(mfccDCTMatrix);
    
    for (i = 0; i < totalFilters; i++) {
        free(mfccFilterWeights[i]);
    }
    free(mfccFilterWeights);
    
    /* Free the feature vector */
    free(ceps);
    
    /* The analysis window */
    delete window;

    free(earMag);
    free(fftMag);
    
    /* Free the FFT */
    free(realOut);
    free(imagOut);

    delete fft;
}


/*
 * 
 * Extract the MFCC on the input frame 
 * 
 */ 
int MFCC::process(const double *inframe, double *outceps)
{
    double *inputData = (double *)malloc(fftSize * sizeof(double));
    for (int i = 0; i < fftSize; ++i) inputData[i] = inframe[i];

    window->cut(inputData);
  
    /* Calculate the fft on the input frame */
    fft->process(0, inputData, realOut, imagOut);

    free(inputData);

    return process(realOut, imagOut, outceps);
}

int MFCC::process(const double *real, const double *imag, double *outceps)
{
    int i, j;

    for (i = 0; i < fftSize/2; ++i) {
        fftMag[i] = sqrt(real[i] * real[i] + imag[i] * imag[i]);
    }

    for (i = 0; i < totalFilters; ++i) {
        earMag[i] = 0.0;
    }

    /* Multiply by mfccFilterWeights */
    for (i = 0; i < totalFilters; i++) {
        double tmp = 0.0;
        for (j = 0; j < fftSize/2; j++) {
            tmp = tmp + (mfccFilterWeights[i][j] * fftMag[j]);
        }
        if (tmp > 0) earMag[i] = log10(tmp);
	else earMag[i] = 0.0;

        if (logPower != 1.0) {
            earMag[i] = pow(earMag[i], logPower);
        }
    }

    /*
     * 
     * Calculate now the cepstral coefficients 
     * with or without the DC component
     *
     */
  
    if (WANT_C0 == 1) {
     
        for (i = 0; i < nceps+1; i++) {
            double tmp = 0.;
            for (j = 0; j < totalFilters; j++){
                tmp = tmp + mfccDCTMatrix[i][j] * earMag[j];
            }
            outceps[i] = tmp;
        }
    }
    else 
    {  
        for (i = 1; i < nceps+1; i++) {
            double tmp = 0.;
            for (j = 0; j < totalFilters; j++){
                tmp = tmp + mfccDCTMatrix[i][j] * earMag[j];
            }
            outceps[i-1] = tmp;
        }
    }
    
    return nceps;
}