eDSP  0.0.1
A cross-platform DSP library written in C++.
hertz2mel.hpp
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1 /*
2 * eDSP, A cross-platform Digital Signal Processing library written in modern C++.
3 * Copyright (C) 2018 Mohammed Boujemaoui Boulaghmoudi, All rights reserved.
4 *
5 * This program is free software: you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the Free
7 * Software Foundation, either version 3 of the License, or (at your option)
8 * any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along width
16 * this program. If not, see <http://www.gnu.org/licenses/>
17 *
18 * Filename: hertz2mel.hpp
19 * Author: Mohammed Boujemaoui
20 * Date: 12/10/18
21 */
22 
23 #ifndef EDSP_HERTZ2MEL_HPP
24 #define EDSP_HERTZ2MEL_HPP
25 
26 #include <cmath>
27 namespace edsp { inline namespace converter {
28 
29  /*
30  * @brief Represent the logarithmic base used in the O'Shaugnessy's book formulas.
31  */
32  enum mel_base {
35  };
36 
37  namespace internal {
38 
39  template <mel_base scale>
40  struct converter {};
41 
42  template<>
43  struct converter<mel_base::base_e> {
44  template<typename T>
45  constexpr T operator()(T f) noexcept {
46  return 1127.01048 * std::log(f / 700.0 + 1.0);
47  }
48  };
49 
50  template<>
51  struct converter<mel_base::base_10> {
52  template<typename T>
53  constexpr T operator()(T f) noexcept {
54  return 2595.0 * std::log10(f / 700.0 + 1.0);
55  }
56  };
57  }
58 
71  template <mel_base scale, typename T>
72  constexpr T hertz2mel(T f) noexcept {
73  return internal::converter<scale, T>{}(f);
74  }
75 
76 }} // namespace edsp::converter
77 
78 #endif //EDSP_HERTZ2MEL_HPP
mel_base
Definition: hertz2mel.hpp:32
Definition: hertz2mel.hpp:34
Definition: amplifier.hpp:29
Definition: hertz2mel.hpp:33
constexpr T hertz2mel(T f) noexcept
Converts a frequency in Hertz into mels.
Definition: hertz2mel.hpp:72