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comparison src/dsp/Resampler.h @ 119:a38d6940f8fb

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Bring in dsp dependencies
author Chris Cannam <c.cannam@qmul.ac.uk>
date Thu, 15 May 2014 12:24:11 +0100
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children ec540b9b6ae5
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118:36bfbc606642 119:a38d6940f8fb
1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
2 /*
3 Constant-Q library
4 Copyright (c) 2013-2014 Queen Mary, University of London
5
6 Permission is hereby granted, free of charge, to any person
7 obtaining a copy of this software and associated documentation
8 files (the "Software"), to deal in the Software without
9 restriction, including without limitation the rights to use, copy,
10 modify, merge, publish, distribute, sublicense, and/or sell copies
11 of the Software, and to permit persons to whom the Software is
12 furnished to do so, subject to the following conditions:
13
14 The above copyright notice and this permission notice shall be
15 included in all copies or substantial portions of the Software.
16
17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
21 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
22 CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
23 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24
25 Except as contained in this notice, the names of the Centre for
26 Digital Music; Queen Mary, University of London; and Chris Cannam
27 shall not be used in advertising or otherwise to promote the sale,
28 use or other dealings in this Software without prior written
29 authorization.
30 */
31
32 #ifndef RESAMPLER_H
33 #define RESAMPLER_H
34
35 #include <vector>
36
37 /**
38 * Resampler resamples a stream from one integer sample rate to
39 * another (arbitrary) rate, using a kaiser-windowed sinc filter. The
40 * results and performance are pretty similar to libraries such as
41 * libsamplerate, though this implementation does not support
42 * time-varying ratios (the ratio is fixed on construction).
43 *
44 * See also Decimator, which is faster and rougher but supports only
45 * power-of-two downsampling factors.
46 */
47 class Resampler
48 {
49 public:
50 /**
51 * Construct a Resampler to resample from sourceRate to
52 * targetRate.
53 */
54 Resampler(int sourceRate, int targetRate);
55
56 /**
57 * Construct a Resampler to resample from sourceRate to
58 * targetRate, using the given filter parameters.
59 */
60 Resampler(int sourceRate, int targetRate,
61 double snr, double bandwidth);
62
63 virtual ~Resampler();
64
65 /**
66 * Read n input samples from src and write resampled data to
67 * dst. The return value is the number of samples written, which
68 * will be no more than ceil((n * targetRate) / sourceRate). The
69 * caller must ensure the dst buffer has enough space for the
70 * samples returned.
71 */
72 int process(const double *src, double *dst, int n);
73
74 /**
75 * Read n input samples from src and return resampled data by
76 * value.
77 */
78 std::vector<double> process(const double *src, int n);
79
80 /**
81 * Return the number of samples of latency at the output due by
82 * the filter. (That is, the output will be delayed by this number
83 * of samples relative to the input.)
84 */
85 int getLatency() const { return m_latency; }
86
87 /**
88 * Carry out a one-off resample of a single block of n
89 * samples. The output is latency-compensated.
90 */
91 static std::vector<double> resample
92 (int sourceRate, int targetRate, const double *data, int n);
93
94 private:
95 int m_sourceRate;
96 int m_targetRate;
97 int m_gcd;
98 int m_filterLength;
99 int m_bufferLength;
100 int m_latency;
101 double m_peakToPole;
102
103 struct Phase {
104 int nextPhase;
105 std::vector<double> filter;
106 int drop;
107 };
108
109 Phase *m_phaseData;
110 int m_phase;
111 std::vector<double> m_buffer;
112 int m_bufferOrigin;
113
114 void initialise(double, double);
115 double reconstructOne();
116 };
117
118 #endif
119