1 // Copyright 2014 Olivier Gillet.
2 //
3 // Author: Olivier Gillet (ol.gillet@gmail.com)
4 //
5 // Permission is hereby granted, free of charge, to any person obtaining a copy
6 // of this software and associated documentation files (the "Software"), to deal
7 // in the Software without restriction, including without limitation the rights
8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // copies of the Software, and to permit persons to whom the Software is
10 // furnished to do so, subject to the following conditions:
11 //
12 // The above copyright notice and this permission notice shall be included in
13 // all copies or substantial portions of the Software.
14 //
15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // THE SOFTWARE.
22 //
23 // See http://creativecommons.org/licenses/MIT/ for more information.
24 //
25 // -----------------------------------------------------------------------------
26 //
27 // Filter bank.
28
29 #include "warps/dsp/filter_bank.h"
30
31 #include <algorithm>
32
33 #include "warps/resources.h"
34
35 namespace warps {
36
37 using namespace std;
38 using namespace stmlib;
39
Init(float sample_rate)40 void FilterBank::Init(float sample_rate) {
41 low_src_down_.Init();
42 low_src_up_.Init();
43 mid_src_down_.Init();
44 mid_src_up_.Init();
45
46 int32_t max_delay = 0;
47 float* samples = &samples_[0];
48
49 int32_t group = -1;
50 int32_t decimation_factor = -1;
51 for (int32_t i = 0; i < kNumBands; ++i) {
52 const float* coefficients = filter_bank_table[i];
53
54 Band& b = band_[i];
55
56 b.decimation_factor = static_cast<int32_t>(coefficients[0]);
57
58 if (b.decimation_factor != decimation_factor) {
59 decimation_factor = b.decimation_factor;
60 ++group;
61 }
62
63 b.group = group;
64 b.sample_rate = sample_rate / static_cast<float>(b.decimation_factor);
65 b.samples = samples;
66 samples += kMaxFilterBankBlockSize / b.decimation_factor;
67
68 b.delay = static_cast<int32_t>(coefficients[1]);
69 b.delay *= b.decimation_factor;
70 b.post_gain = coefficients[2];
71
72 max_delay = max(max_delay, b.delay);
73 for (int32_t pass = 0; pass < 2; ++pass) {
74 b.svf[pass].Init();
75 b.svf[pass].set_f_fq(
76 coefficients[pass * 2 + 3],
77 coefficients[pass * 2 + 4]);
78 }
79 }
80 band_[kNumBands].group = band_[kNumBands - 1].group + 1;
81 max_delay = min(max_delay, int32_t(256));
82 float* delay_ptr = &delay_buffer_[0];
83 for (int32_t i = 0; i < kNumBands; ++i) {
84 Band& b = band_[i];
85 int32_t compensation = max_delay - b.delay;
86 if (b.group == 0) {
87 compensation -= kLowFactor * \
88 (low_src_down_.delay() + low_src_up_.delay());
89 compensation -= mid_src_down_.delay();
90 compensation -= mid_src_up_.delay();
91 } else if (b.group == 1) {
92 compensation -= mid_src_down_.delay();
93 compensation -= mid_src_up_.delay();
94 }
95 compensation = max(compensation - b.decimation_factor / 2, int32_t(0));
96 b.delay_line.Init(delay_ptr, compensation / b.decimation_factor);
97 delay_ptr += b.delay_line.size();
98 }
99 }
100
Analyze(const float * in,size_t size)101 void FilterBank::Analyze(const float* in, size_t size) {
102 mid_src_down_.Process(in, tmp_[0], size);
103 low_src_down_.Process(tmp_[0], tmp_[1], size / kMidFactor);
104
105 const float* sources[3] = { tmp_[1], tmp_[0], in };
106 for (int32_t i = 0; i < kNumBands; ++i) {
107 Band& b = band_[i];
108 const size_t band_size = size / b.decimation_factor;
109 const float* input = sources[b.group];
110
111 for (int32_t pass = 0; pass < 2; ++pass) {
112 const float* source = pass == 0 ? input : b.samples;
113 float* destination = b.samples;
114 if (i == 0) {
115 b.svf[pass].Process<FILTER_MODE_LOW_PASS>(
116 source, destination, band_size);
117 } else if (i == kNumBands - 1) {
118 b.svf[pass].Process<FILTER_MODE_HIGH_PASS>(
119 source, destination, band_size);
120 } else {
121 b.svf[pass].Process<FILTER_MODE_BAND_PASS_NORMALIZED>(
122 source, destination, band_size);
123 }
124 }
125 // Apply post-gain
126 const float gain = b.post_gain;
127 float* output = b.samples;
128 for (size_t i = 0; i < band_size; ++i) {
129 output[i] *= gain;
130 }
131 }
132 }
133
Synthesize(float * out,size_t size)134 void FilterBank::Synthesize(float* out, size_t size) {
135 float* buffers[3] = { tmp_[1], tmp_[0], out };
136
137 fill(&buffers[0][0], &buffers[0][size / band_[0].decimation_factor], 0.0f);
138 for (int32_t i = 0; i < kNumBands; ++i) {
139 Band& b = band_[i];
140
141 size_t band_size = size / b.decimation_factor;
142 float* s = buffers[b.group];
143 for (size_t j = 0; j < band_size; ++j) {
144 s[j] += b.delay_line.ReadWrite(b.samples[j]);
145 }
146
147 if (band_[i + 1].group != b.group) {
148 if (b.group == 0) {
149 low_src_up_.Process(tmp_[1], tmp_[0], band_size);
150 } else if (b.group == 1) {
151 mid_src_up_.Process(tmp_[0], out, band_size);
152 }
153 }
154 }
155 }
156
157 } // namespace warps
158