OpenShot Library | OpenShotAudio 0.2.2
juce_LagrangeInterpolator.h
1
2/** @weakgroup juce_audio_basics-utilities
3 * @{
4 */
5/*
6 ==============================================================================
7
8 This file is part of the JUCE library.
9 Copyright (c) 2017 - ROLI Ltd.
10
11 JUCE is an open source library subject to commercial or open-source
12 licensing.
13
14 The code included in this file is provided under the terms of the ISC license
15 http://www.isc.org/downloads/software-support-policy/isc-license. Permission
16 To use, copy, modify, and/or distribute this software for any purpose with or
17 without fee is hereby granted provided that the above copyright notice and
18 this permission notice appear in all copies.
19
20 JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
21 EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
22 DISCLAIMED.
23
24 ==============================================================================
25*/
26
27namespace juce
28{
29
30/**
31 Interpolator for resampling a stream of floats using 4-point lagrange interpolation.
32
33 Note that the resampler is stateful, so when there's a break in the continuity
34 of the input stream you're feeding it, you should call reset() before feeding
35 it any new data. And like with any other stateful filter, if you're resampling
36 multiple channels, make sure each one uses its own LagrangeInterpolator
37 object.
38
39 @see CatmullRomInterpolator
40
41 @tags{Audio}
42*/
44{
45public:
46 LagrangeInterpolator() noexcept;
47 ~LagrangeInterpolator() noexcept;
48
49 LagrangeInterpolator (LagrangeInterpolator&&) noexcept = default;
50 LagrangeInterpolator& operator= (LagrangeInterpolator&&) noexcept = default;
51
52 /** Resets the state of the interpolator.
53 Call this when there's a break in the continuity of the input data stream.
54 */
55 void reset() noexcept;
56
57 /** Resamples a stream of samples.
58
59 @param speedRatio the number of input samples to use for each output sample
60 @param inputSamples the source data to read from. This must contain at
61 least (speedRatio * numOutputSamplesToProduce) samples.
62 @param outputSamples the buffer to write the results into
63 @param numOutputSamplesToProduce the number of output samples that should be created
64
65 @returns the actual number of input samples that were used
66 */
67 int process (double speedRatio,
68 const float* inputSamples,
69 float* outputSamples,
70 int numOutputSamplesToProduce) noexcept;
71
72 /** Resamples a stream of samples.
73
74 @param speedRatio the number of input samples to use for each output sample
75 @param inputSamples the source data to read from. This must contain at
76 least (speedRatio * numOutputSamplesToProduce) samples.
77 @param outputSamples the buffer to write the results into
78 @param numOutputSamplesToProduce the number of output samples that should be created
79 @param available the number of available input samples. If it needs more samples
80 than available, it either wraps back for wrapAround samples, or
81 it feeds zeroes
82 @param wrapAround if the stream exceeds available samples, it wraps back for
83 wrapAround samples. If wrapAround is set to 0, it will feed zeroes.
84
85 @returns the actual number of input samples that were used
86 */
87 int process (double speedRatio,
88 const float* inputSamples,
89 float* outputSamples,
90 int numOutputSamplesToProduce,
91 int available,
92 int wrapAround) noexcept;
93
94 /** Resamples a stream of samples, adding the results to the output data
95 with a gain.
96
97 @param speedRatio the number of input samples to use for each output sample
98 @param inputSamples the source data to read from. This must contain at
99 least (speedRatio * numOutputSamplesToProduce) samples.
100 @param outputSamples the buffer to write the results to - the result values will be added
101 to any pre-existing data in this buffer after being multiplied by
102 the gain factor
103 @param numOutputSamplesToProduce the number of output samples that should be created
104 @param gain a gain factor to multiply the resulting samples by before
105 adding them to the destination buffer
106
107 @returns the actual number of input samples that were used
108 */
109 int processAdding (double speedRatio,
110 const float* inputSamples,
111 float* outputSamples,
112 int numOutputSamplesToProduce,
113 float gain) noexcept;
114
115 /** Resamples a stream of samples, adding the results to the output data
116 with a gain.
117
118 @param speedRatio the number of input samples to use for each output sample
119 @param inputSamples the source data to read from. This must contain at
120 least (speedRatio * numOutputSamplesToProduce) samples.
121 @param outputSamples the buffer to write the results to - the result values will be added
122 to any pre-existing data in this buffer after being multiplied by
123 the gain factor
124 @param numOutputSamplesToProduce the number of output samples that should be created
125 @param available the number of available input samples. If it needs more samples
126 than available, it either wraps back for wrapAround samples, or
127 it feeds zeroes
128 @param wrapAround if the stream exceeds available samples, it wraps back for
129 wrapAround samples. If wrapAround is set to 0, it will feed zeroes.
130 @param gain a gain factor to multiply the resulting samples by before
131 adding them to the destination buffer
132
133 @returns the actual number of input samples that were used
134 */
135 int processAdding (double speedRatio,
136 const float* inputSamples,
137 float* outputSamples,
138 int numOutputSamplesToProduce,
139 int available,
140 int wrapAround,
141 float gain) noexcept;
142
143private:
144 float lastInputSamples[5];
145 double subSamplePos;
146
147 JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (LagrangeInterpolator)
148};
149
150} // namespace juce
151
152/** @}*/
Interpolator for resampling a stream of floats using 4-point lagrange interpolation.
#define JUCE_API
This macro is added to all JUCE public class declarations.