1 // Copyright (C) 2010-2016 Lukas Lalinsky
2 // Distributed under the MIT license, see the LICENSE file for details.
3
4 #include <limits>
5 #include <cmath>
6 #include "fft_frame.h"
7 #include "utils.h"
8 #include "chroma.h"
9 #include "debug.h"
10
11 namespace chromaprint {
12
13 static const int NUM_BANDS = 12;
14
FreqToOctave(double freq,double base=440.0/16.0)15 inline double FreqToOctave(double freq, double base = 440.0 / 16.0)
16 {
17 return log(freq / base) / log(2.0);
18 }
19
Chroma(int min_freq,int max_freq,int frame_size,int sample_rate,FeatureVectorConsumer * consumer)20 Chroma::Chroma(int min_freq, int max_freq, int frame_size, int sample_rate, FeatureVectorConsumer *consumer)
21 : m_interpolate(false),
22 m_notes(frame_size),
23 m_notes_frac(frame_size),
24 m_features(NUM_BANDS),
25 m_consumer(consumer)
26 {
27 PrepareNotes(min_freq, max_freq, frame_size, sample_rate);
28 }
29
~Chroma()30 Chroma::~Chroma()
31 {
32 }
33
PrepareNotes(int min_freq,int max_freq,int frame_size,int sample_rate)34 void Chroma::PrepareNotes(int min_freq, int max_freq, int frame_size, int sample_rate)
35 {
36 m_min_index = std::max(1, FreqToIndex(min_freq, frame_size, sample_rate));
37 m_max_index = std::min(frame_size / 2, FreqToIndex(max_freq, frame_size, sample_rate));
38 for (int i = m_min_index; i < m_max_index; i++) {
39 double freq = IndexToFreq(i, frame_size, sample_rate);
40 double octave = FreqToOctave(freq);
41 double note = NUM_BANDS * (octave - floor(octave));
42 m_notes[i] = (char)note;
43 m_notes_frac[i] = note - m_notes[i];
44 }
45 }
46
Reset()47 void Chroma::Reset()
48 {
49 }
50
Consume(const FFTFrame & frame)51 void Chroma::Consume(const FFTFrame &frame)
52 {
53 fill(m_features.begin(), m_features.end(), 0.0);
54 for (int i = m_min_index; i < m_max_index; i++) {
55 int note = m_notes[i];
56 double energy = frame[i];
57 if (m_interpolate) {
58 int note2 = note;
59 double a = 1.0;
60 if (m_notes_frac[i] < 0.5) {
61 note2 = (note + NUM_BANDS - 1) % NUM_BANDS;
62 a = 0.5 + m_notes_frac[i];
63 }
64 if (m_notes_frac[i] > 0.5) {
65 note2 = (note + 1) % NUM_BANDS;
66 a = 1.5 - m_notes_frac[i];
67 }
68 m_features[note] += energy * a;
69 m_features[note2] += energy * (1.0 - a);
70 }
71 else {
72 m_features[note] += energy;
73 }
74 }
75 m_consumer->Consume(m_features);
76 }
77
78 }; // namespace chromaprint
79