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- /*
- Sekai - addons for the WORLD speech toolkit
- Copyright (C) 2016 Tobias Platen
- 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/>.
- */
- #include <math.h>
- const static double A4Frequency = 440.0;
- const static double A4Note = 69.0;
- // based on
- // https://github.com/haruneko/SimpleSynthesizer/blob/master/core/org/stand/util/MusicalNote.{h,cpp}
- double frequencyFromNote(float note) {
- if (note == 0) return 0;
- return pow(2.0, (note - A4Note) / 12.0) * A4Frequency;
- }
- float noteFromFrequency(double frequency) {
- if (frequency == 0) return 0;
- return A4Note + 12.0 * log2(frequency / A4Frequency);
- }
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