90 lines
2.0 KiB
C++
90 lines
2.0 KiB
C++
/***
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Olive - Non-Linear Video Editor
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Copyright (C) 2021 Olive Team
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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 3 of the License, or
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(at your option) any later version.
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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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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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***/
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#ifndef DECIBEL_H
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#define DECIBEL_H
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#include <QtGlobal>
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#include <cmath>
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namespace olive {
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class Decibel
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{
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public:
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static double fromLinear(double linear)
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{
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return double(20.0) * std::log10(linear);
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}
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static double toLinear(double decibel)
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{
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double to_linear = std::pow(double(10.0), decibel / double(20.0));
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// Minimum threshold that we figure is close enough to 0 that we may as well just return 0
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if (to_linear < 0.000001) {
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return 0;
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} else {
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return to_linear;
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}
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}
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static double fromLogarithmic(double logarithmic)
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{
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if (logarithmic < 0.001)
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return -200.0;
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else if (logarithmic > 0.99)
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return 0;
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else
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return 20.0 * std::log10(-std::log(1 - logarithmic) / LOG100);
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}
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static double toLogarithmic(double decibel)
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{
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if (qFuzzyIsNull(decibel)) {
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return 1;
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} else {
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return 1 - std::exp(-std::pow(10.0, decibel / 20.0) * LOG100);
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}
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}
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static double LinearToLogarithmic(double linear)
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{
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return 1 - std::exp(-linear * LOG100);
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}
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static double LogarithmicToLinear(double logarithmic)
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{
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if (logarithmic > 0.99) {
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return 1;
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} else {
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return -std::log(1 - logarithmic) / LOG100;
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}
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}
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private:
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static constexpr double LOG100 = 4.60517018599;
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};
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}
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#endif // DECIBEL_H
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