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/*
* Copyright (C) 2007-2011 Paul Davis <paul@linuxaudiosystems.com>
* Copyright (C) 2009-2014 David Robillard <d@drobilla.net>
* Copyright (C) 2013-2015 Robin Gareus <robin@gareus.org>
*
* 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.
*
* 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef __ardour_dB_h__
#define __ardour_dB_h__
#include <limits>
#include "pbd/fastlog.h"
#define GAIN_COEFF_ZERO 0.f
#define GAIN_COEFF_SMALL 0.0000001f //-140dB
#define GAIN_COEFF_UNITY 1.f
static inline float dB_to_coefficient (float dB) {
return dB > -318.8f ? pow (10.0f, dB * 0.05f) : 0.0f;
}
static inline float fast_coefficient_to_dB (float coeff) {
return 20.0f * fast_log10 (coeff);
}
static inline float accurate_coefficient_to_dB (float coeff) {
if (coeff < 1e-15) return -std::numeric_limits<float>::infinity();
return 20.0f * log10f (coeff);
}
static inline double dB_coeff_step(double max_coeff) {
const double max_db = lrint(accurate_coefficient_to_dB(max_coeff));
return 0.1 * (max_coeff / max_db);
}
extern double zero_db_as_fraction;
#endif /* __ardour_dB_h__ */
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