1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
/* Copyright (C) 2015-2017 Sergey V. Mikayev
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <cmath>
#include <cstddef>
#include "ResamplerModel.h"
#include "ResamplerStage.h"
#include "SincResampler.h"
#include "IIR2xResampler.h"
#include "LinearResampler.h"
namespace SRCTools {
namespace ResamplerModel {
static const unsigned int CHANNEL_COUNT = 2;
static const unsigned int MAX_SAMPLES_PER_RUN = 4096;
class CascadeStage : public FloatSampleProvider {
friend void freeResamplerModel(FloatSampleProvider &model, FloatSampleProvider &source);
public:
CascadeStage(FloatSampleProvider &source, ResamplerStage &resamplerStage);
void getOutputSamples(FloatSample *outBuffer, unsigned int size);
protected:
ResamplerStage &resamplerStage;
private:
FloatSampleProvider &source;
FloatSample buffer[CHANNEL_COUNT * MAX_SAMPLES_PER_RUN];
const FloatSample *bufferPtr;
unsigned int size;
};
class InternalResamplerCascadeStage : public CascadeStage {
public:
InternalResamplerCascadeStage(FloatSampleProvider &useSource, ResamplerStage &useResamplerStage) :
CascadeStage(useSource, useResamplerStage)
{}
~InternalResamplerCascadeStage() {
delete &resamplerStage;
}
};
} // namespace ResamplerModel
} // namespace SRCTools
using namespace SRCTools;
FloatSampleProvider &ResamplerModel::createResamplerModel(FloatSampleProvider &source, double sourceSampleRate, double targetSampleRate, Quality quality) {
if (sourceSampleRate == targetSampleRate) {
return source;
}
if (quality == FASTEST) {
return *new InternalResamplerCascadeStage(source, *new LinearResampler(sourceSampleRate, targetSampleRate));
}
const IIRResampler::Quality iirQuality = static_cast<IIRResampler::Quality>(quality);
const double iirPassbandFraction = IIRResampler::getPassbandFractionForQuality(iirQuality);
if (sourceSampleRate < targetSampleRate) {
ResamplerStage *iir2xInterpolator = new IIR2xInterpolator(iirQuality);
FloatSampleProvider &iir2xInterpolatorStage = *new InternalResamplerCascadeStage(source, *iir2xInterpolator);
if (2.0 * sourceSampleRate == targetSampleRate) {
return iir2xInterpolatorStage;
}
double passband = 0.5 * sourceSampleRate * iirPassbandFraction;
double stopband = 1.5 * sourceSampleRate;
ResamplerStage *sincResampler = SincResampler::createSincResampler(2.0 * sourceSampleRate, targetSampleRate, passband, stopband, DEFAULT_DB_SNR, DEFAULT_WINDOWED_SINC_MAX_UPSAMPLE_FACTOR);
return *new InternalResamplerCascadeStage(iir2xInterpolatorStage, *sincResampler);
}
if (sourceSampleRate == 2.0 * targetSampleRate) {
ResamplerStage *iir2xDecimator = new IIR2xDecimator(iirQuality);
return *new InternalResamplerCascadeStage(source, *iir2xDecimator);
}
double passband = 0.5 * targetSampleRate * iirPassbandFraction;
double stopband = 1.5 * targetSampleRate;
double sincOutSampleRate = 2.0 * targetSampleRate;
const unsigned int maxUpsampleFactor = static_cast<unsigned int>(ceil(DEFAULT_WINDOWED_SINC_MAX_DOWNSAMPLE_FACTOR * sincOutSampleRate / sourceSampleRate));
ResamplerStage *sincResampler = SincResampler::createSincResampler(sourceSampleRate, sincOutSampleRate, passband, stopband, DEFAULT_DB_SNR, maxUpsampleFactor);
FloatSampleProvider &sincResamplerStage = *new InternalResamplerCascadeStage(source, *sincResampler);
ResamplerStage *iir2xDecimator = new IIR2xDecimator(iirQuality);
return *new InternalResamplerCascadeStage(sincResamplerStage, *iir2xDecimator);
}
FloatSampleProvider &ResamplerModel::createResamplerModel(FloatSampleProvider &source, ResamplerStage **resamplerStages, unsigned int stageCount) {
FloatSampleProvider *prevStage = &source;
for (unsigned int i = 0; i < stageCount; i++) {
prevStage = new CascadeStage(*prevStage, *(resamplerStages[i]));
}
return *prevStage;
}
FloatSampleProvider &ResamplerModel::createResamplerModel(FloatSampleProvider &source, ResamplerStage &stage) {
return *new CascadeStage(source, stage);
}
void ResamplerModel::freeResamplerModel(FloatSampleProvider &model, FloatSampleProvider &source) {
FloatSampleProvider *currentStage = &model;
while (currentStage != &source) {
CascadeStage *cascadeStage = dynamic_cast<CascadeStage *>(currentStage);
if (cascadeStage == NULL) return;
FloatSampleProvider &prevStage = cascadeStage->source;
delete currentStage;
currentStage = &prevStage;
}
}
using namespace ResamplerModel;
CascadeStage::CascadeStage(FloatSampleProvider &useSource, ResamplerStage &useResamplerStage) :
resamplerStage(useResamplerStage),
source(useSource),
bufferPtr(buffer),
size()
{}
void CascadeStage::getOutputSamples(FloatSample *outBuffer, unsigned int length) {
while (length > 0) {
if (size == 0) {
size = resamplerStage.estimateInLength(length);
if (size < 1) {
size = 1;
} else if (MAX_SAMPLES_PER_RUN < size) {
size = MAX_SAMPLES_PER_RUN;
}
source.getOutputSamples(buffer, size);
bufferPtr = buffer;
}
resamplerStage.process(bufferPtr, size, outBuffer, length);
}
}
|
