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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
Sonic Visualiser
An audio file viewer and annotation editor.
Centre for Digital Music, Queen Mary, University of London.
This file copyright 2006 Chris Cannam.
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 SV_PITCH_H
#define SV_PITCH_H
#include <QString>
namespace sv {
class Pitch
{
public:
/**
* Return the frequency at the given MIDI pitch plus centsOffset
* cents (1/100ths of a semitone). centsOffset does not have to
* be in any particular range or sign.
*
* If concertA is non-zero, use that as the reference frequency
* for the A at MIDI pitch 69; otherwise use the tuning frequency
* specified in the application preferences (default 440Hz).
*/
static double getFrequencyForPitch(int midiPitch,
double centsOffset = 0,
double concertA = 0.0);
/**
* Return the nearest MIDI pitch to the given frequency.
*
* If centsOffsetReturn is non-NULL, return in *centsOffsetReturn
* the number of cents (1/100ths of a semitone) difference between
* the given frequency and that of the returned MIDI pitch. The
* cents offset will be in the range [-50,50).
*
* If concertA is non-zero, use that as the reference frequency
* for the A at MIDI pitch 69; otherwise use the tuning frequency
* specified in the application preferences (default 440Hz).
*/
static int getPitchForFrequency(double frequency,
double *centsOffsetReturn = 0,
double concertA = 0.0);
/**
* Compatibility version of getPitchForFrequency accepting float
* pointer argument.
*/
static int getPitchForFrequency(double frequency,
float *centsOffsetReturn,
double concertA = 0.0) {
double c;
int p = getPitchForFrequency(frequency, &c, concertA);
if (centsOffsetReturn) *centsOffsetReturn = float(c);
return p;
}
/**
* Return the nearest MIDI pitch range to the given frequency
* range, that is, the difference in MIDI pitch values between the
* higher and lower frequencies.
*
* If centsOffsetReturn is non-NULL, return in *centsOffsetReturn
* the number of cents (1/100ths of a semitone) difference between
* the given frequency difference and the returned MIDI pitch
* range. The cents offset will be in the range [-50,50).
*
* If concertA is non-zero, use that as the reference frequency
* for the A at MIDI pitch 69; otherwise use the tuning frequency
* specified in the application preferences (default 440Hz).
*/
static int getPitchForFrequencyDifference(double frequencyA,
double frequencyB,
double *centsOffsetReturn = 0,
double concertA = 0.0);
/**
* Compatibility version of getPitchForFrequencyDifference
* accepting float pointer argument.
*/
static int getPitchForFrequencyDifference(double frequencyA,
double frequencyB,
float *centsOffsetReturn,
double concertA = 0.0) {
double c;
int p = getPitchForFrequencyDifference(frequencyA, frequencyB,
&c, concertA);
if (centsOffsetReturn) *centsOffsetReturn = float(c);
return p;
}
/**
* Return the MIDI pitch for the given note number (0-12 where 0
* is C) and octave number. The octave numbering system is based
* on the application preferences (default is C4 = middle C,
* though in previous SV releases that was C3).
*/
static int getPitchForNoteAndOctave(int note, int octave);
/**
* Return the note number (0-12 where 0 is C) and octave number
* for the given MIDI pitch. The octave numbering system is based
* on the application preferences (default is C4 = middle C,
* though in previous SV releases that was C3).
*/
static void getNoteAndOctaveForPitch(int midiPitch, int ¬e, int &octave);
/**
* Return a string describing the given MIDI pitch, with optional
* cents offset. This consists of the note name, octave number,
* and optional cents. The octave numbering system is based on the
* application preferences (default is C4 = middle C, though in
* previous SV releases that was C3).
*
* For example, "A#3" (A# in octave 3) or "C2-12c" (C in octave 2,
* minus 12 cents).
*
* If useFlats is true, spell notes with flats instead of sharps,
* e.g. Bb3 instead of A#3.
*/
static QString getPitchLabel(int midiPitch,
double centsOffset = 0,
bool useFlats = false);
/**
* Return a string describing the nearest MIDI pitch to the given
* frequency, with cents offset.
*
* If concertA is non-zero, use that as the reference frequency
* for the A at MIDI pitch 69; otherwise use the tuning frequency
* specified in the application preferences (default 440Hz).
*
* If useFlats is true, spell notes with flats instead of sharps,
* e.g. Bb3 instead of A#3.
*/
static QString getPitchLabelForFrequency(double frequency,
double concertA = 0.0,
bool useFlats = false);
/**
* Return a string describing the given pitch range in octaves,
* semitones and cents. This is in the form e.g. "1'2+4c".
*/
static QString getLabelForPitchRange(int semis, double cents = 0);
/**
* Return true if the given frequency falls within the range of
* MIDI note pitches, plus or minus half a semitone. This is
* equivalent to testing whether getPitchForFrequency returns a
* pitch in the MIDI range (0 to 127 inclusive) with any cents
* offset.
*
* If concertA is non-zero, use that as the reference frequency
* for the A at MIDI pitch 69; otherwise use the tuning frequency
* specified in the application preferences (default 440Hz).
*/
static bool isFrequencyInMidiRange(double frequency,
double concertA = 0.0);
/**
* Choice of formula for mel-scale conversions.
* OShaughnessy: 2595 * log_10 (1 + f/700)
* Fant: 1000 / log(2) * log (1 + f/1000)
* Slaney: 3f/200 (f<1000), 15 + 27log_6.4(f/1000) (f>=1000)
*/
enum class MelFormula {
OShaughnessy,
Fant,
Slaney
};
/**
* Convert a frequency to a mel-scale value.
*/
static double getMelForFrequency(double frequency, MelFormula);
/**
* Convert a mel-scale value to a frequency.
*/
static double getFrequencyForMel(double mel, MelFormula);
};
} // end namespace sv
#endif
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