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equalizer.h
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equalizer.h
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/*
* Copyright (c) 2014, Vojtech Vasek
*
* 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 3 of the License, or
* (at your option) any later version.
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/*
* ==============================================================================
*
* Filename: equalizer.h
*
* Description: This module contains functions for work with Octave, bands,
* sound modification and the Fourier transform itself.
* Octave and its bands are counted here from given
* base frequency and fraction denominator.
* Three window functions are Hamming(hammingWindow),
* Planck(planckWindow) and Tukey(tukeyWindow). Sound
* modification functions are called Flat(flatBand),
* Peak(peakBand) and Next(nextBand).
*
* Author: Vojtech Vasek
*
* ==============================================================================
*/
#ifndef EQUALIZER_H_
#define EQUALIZER_H_
#include "complex.h"
#include "wave.h"
/*
* One band structure contains information about specific band
* of frequencies, which are controllable together. Variables
* are in Hz units.
*/
struct band {
double center;
double upperE;
double lowerE;
struct band *next;
};
/*
* Stores informations about selected Octave, which includes
* number of all bands, selected fraction and bands itself
* as a linked list.
*/
struct octave {
struct band *head; // Head of the linked list
int frac; // Selected Octave fraction (bigger means more bands to control)
int len; // Number of elements in linked list
};
extern struct octave *initOctave(int base, int frac);
extern void freeOctave(struct octave *);
extern struct band *getBand(struct octave *, int band_id);
extern void modulateFreq(C_ARRAY *, int st, int tg, double mult, double adit, int srate);
extern void modulateBand(C_ARRAY *, struct octave *, int index, double mult, double adit, int sample_rate);
extern void flatBand(C_ARRAY *, struct band *, int sample_rate, double gain);
extern void peakBand(C_ARRAY *, struct band *, int sample_rate, double gain);
extern void nextBand(C_ARRAY *, struct band *, int sample_rate, double gain);
extern void hammingWindow(C_ARRAY *ca, double alpha, double beta);
extern void planckWindow(C_ARRAY *ca, double epsilon);
extern void tukeyWindow(C_ARRAY *ca, double alpha);
extern C_ARRAY *fft(C_ARRAY *ca);
extern C_ARRAY *ifft(C_ARRAY *ca);
#endif