view MeanFilter.h @ 137:109c3a2ad930 vamp-fft-revision

Make use of new Vamp FFT interface. This reduces the runtime of the regression test from 5.7 to 2.2 seconds on this machine, but it does need the right version of the SDK, which is currently only available in the vampipe branch.

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

/*
    pYIN - A fundamental frequency estimator for monophonic audio
    Centre for Digital Music, Queen Mary, University of London.
    
    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.
*/

#ifndef _MEAN_FILTER_H_
#define _MEAN_FILTER_H_

class MeanFilter
{
public:
    /**
     * Construct a non-causal mean filter with filter length flen,
     * that replaces each sample N with the mean of samples
     * [N-floor(F/2) .. N+floor(F/2)] where F is the filter length.
     * Only odd F are supported.
     */
    MeanFilter(int flen) : m_flen(flen) { }
    ~MeanFilter() { }

    /**
     * Filter the n samples in "in" and place the results in "out"
     */
    void filter(const double *in, double *out, const int n) {
	filterSubsequence(in, out, n, n, 0);
    }

    /**
     * Filter the n samples starting at the given offset in the
     * m-element array "in" and place the results in the n-element
     * array "out"
     */
    void filterSubsequence(const double *in, double *out,
			   const int m, const int n,
			   const int offset) {
	int half = m_flen/2;
	for (int i = 0; i < n; ++i) {
	    double v = 0;
	    int n = 0;
	    for (int j = -half; j <= half; ++j) {
		int ix = i + j + offset;
		if (ix >= 0 && ix < m) {
		    v += in[ix];
		    ++n;
		}
	    }
	    out[i] = v / n;
	}
    }

private:
    int m_flen;
};

#endif