52 lines
1.7 KiB
C++
52 lines
1.7 KiB
C++
/*
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* Copyright (C) 2007-2011 Paul Davis <paul@linuxaudiosystems.com>
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* Copyright (C) 2009-2014 David Robillard <d@drobilla.net>
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* Copyright (C) 2013-2015 Robin Gareus <robin@gareus.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef __ardour_dB_h__
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#define __ardour_dB_h__
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#include <limits>
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#include "pbd/fastlog.h"
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#define GAIN_COEFF_ZERO 0.f
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#define GAIN_COEFF_SMALL 0.0000001f //-140dB
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#define GAIN_COEFF_UNITY 1.f
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static inline float dB_to_coefficient (float dB) {
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return dB > -318.8f ? pow (10.0f, dB * 0.05f) : 0.0f;
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}
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static inline float fast_coefficient_to_dB (float coeff) {
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return 20.0f * fast_log10 (coeff);
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}
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static inline float accurate_coefficient_to_dB (float coeff) {
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if (coeff < 1e-15) return -std::numeric_limits<float>::infinity();
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return 20.0f * log10f (coeff);
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}
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static inline double dB_coeff_step(double max_coeff) {
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const double max_db = lrint(accurate_coefficient_to_dB(max_coeff));
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return 0.1 * (max_coeff / max_db);
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}
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extern double zero_db_as_fraction;
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#endif /* __ardour_dB_h__ */
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