annotate vamp/Pitch.cpp @ 125:b3f72e67e543

Ah, CQKernel does need to be public (it's included by other public headers)

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
/*
    Constant-Q library
    Copyright (c) 2013-2014 Queen Mary, University of London

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use, copy,
    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

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    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the names of the Centre for
    Digital Music; Queen Mary, University of London; and Chris Cannam
    shall not be used in advertising or otherwise to promote the sale,
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*/

#include "Pitch.h"

#include <math.h>

float
Pitch::getFrequencyForPitch(int midiPitch,
			    float centsOffset,
			    float concertA)
{
    float p = float(midiPitch) + (centsOffset / 100);
    return concertA * powf(2.0, (p - 69.0) / 12.0);
}

int
Pitch::getPitchForFrequency(float frequency,
			    float *centsOffsetReturn,
			    float concertA)
{
    float p = 12.0 * (log(frequency / (concertA / 2.0)) / log(2.0)) + 57.0;

    int midiPitch = int(p + 0.00001);
    float centsOffset = (p - midiPitch) * 100.0;

    if (centsOffset >= 50.0) {
	midiPitch = midiPitch + 1;
	centsOffset = -(100.0 - centsOffset);
    }
    
    if (centsOffsetReturn) *centsOffsetReturn = centsOffset;
    return midiPitch;
}