Line data Source code
1 : ////////////////////////////////////////////////////////////////////////////////
2 : ///
3 : /// Sample rate transposer. Changes sample rate by using linear interpolation
4 : /// together with anti-alias filtering (first order interpolation with anti-
5 : /// alias filtering should be quite adequate for this application).
6 : ///
7 : /// Use either of the derived classes of 'RateTransposerInteger' or
8 : /// 'RateTransposerFloat' for corresponding integer/floating point tranposing
9 : /// algorithm implementation.
10 : ///
11 : /// Author : Copyright (c) Olli Parviainen
12 : /// Author e-mail : oparviai 'at' iki.fi
13 : /// SoundTouch WWW: http://www.surina.net/soundtouch
14 : ///
15 : ////////////////////////////////////////////////////////////////////////////////
16 : //
17 : // Last changed : $Date: 2014-04-06 15:57:21 +0000 (Sun, 06 Apr 2014) $
18 : // File revision : $Revision: 4 $
19 : //
20 : // $Id: RateTransposer.h 195 2014-04-06 15:57:21Z oparviai $
21 : //
22 : ////////////////////////////////////////////////////////////////////////////////
23 : //
24 : // License :
25 : //
26 : // SoundTouch audio processing library
27 : // Copyright (c) Olli Parviainen
28 : //
29 : // This library is free software; you can redistribute it and/or
30 : // modify it under the terms of the GNU Lesser General Public
31 : // License as published by the Free Software Foundation; either
32 : // version 2.1 of the License, or (at your option) any later version.
33 : //
34 : // This library is distributed in the hope that it will be useful,
35 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
36 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
37 : // Lesser General Public License for more details.
38 : //
39 : // You should have received a copy of the GNU Lesser General Public
40 : // License along with this library; if not, write to the Free Software
41 : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
42 : //
43 : ////////////////////////////////////////////////////////////////////////////////
44 :
45 : #ifndef RateTransposer_H
46 : #define RateTransposer_H
47 :
48 : #include <stddef.h>
49 : #include "AAFilter.h"
50 : #include "FIFOSamplePipe.h"
51 : #include "FIFOSampleBuffer.h"
52 :
53 : #include "STTypes.h"
54 :
55 : namespace soundtouch
56 : {
57 :
58 : /// Abstract base class for transposer implementations (linear, advanced vs integer, float etc)
59 : class TransposerBase
60 : {
61 : public:
62 : enum ALGORITHM {
63 : LINEAR = 0,
64 : CUBIC,
65 : SHANNON
66 : };
67 :
68 : protected:
69 : virtual void resetRegisters() = 0;
70 :
71 : virtual int transposeMono(SAMPLETYPE *dest,
72 : const SAMPLETYPE *src,
73 : int &srcSamples) = 0;
74 : virtual int transposeStereo(SAMPLETYPE *dest,
75 : const SAMPLETYPE *src,
76 : int &srcSamples) = 0;
77 : virtual int transposeMulti(SAMPLETYPE *dest,
78 : const SAMPLETYPE *src,
79 : int &srcSamples) = 0;
80 :
81 : static ALGORITHM algorithm;
82 :
83 : public:
84 : float rate;
85 : int numChannels;
86 :
87 : TransposerBase();
88 : virtual ~TransposerBase();
89 :
90 : virtual int transpose(FIFOSampleBuffer &dest, FIFOSampleBuffer &src);
91 : virtual void setRate(float newRate);
92 : virtual void setChannels(int channels);
93 :
94 : // static factory function
95 : static TransposerBase *newInstance();
96 :
97 : // static function to set interpolation algorithm
98 : static void setAlgorithm(ALGORITHM a);
99 : };
100 :
101 :
102 : /// A common linear samplerate transposer class.
103 : ///
104 : class RateTransposer : public FIFOProcessor
105 : {
106 : protected:
107 : /// Anti-alias filter object
108 : AAFilter *pAAFilter;
109 : TransposerBase *pTransposer;
110 :
111 : /// Buffer for collecting samples to feed the anti-alias filter between
112 : /// two batches
113 : FIFOSampleBuffer inputBuffer;
114 :
115 : /// Buffer for keeping samples between transposing & anti-alias filter
116 : FIFOSampleBuffer midBuffer;
117 :
118 : /// Output sample buffer
119 : FIFOSampleBuffer outputBuffer;
120 :
121 : bool bUseAAFilter;
122 :
123 :
124 : /// Transposes sample rate by applying anti-alias filter to prevent folding.
125 : /// Returns amount of samples returned in the "dest" buffer.
126 : /// The maximum amount of samples that can be returned at a time is set by
127 : /// the 'set_returnBuffer_size' function.
128 : void processSamples(const SAMPLETYPE *src,
129 : uint numSamples);
130 :
131 : public:
132 : RateTransposer();
133 : virtual ~RateTransposer();
134 :
135 : /// Operator 'new' is overloaded so that it automatically creates a suitable instance
136 : /// depending on if we're to use integer or floating point arithmetics.
137 : // static void *operator new(size_t s);
138 :
139 : /// Use this function instead of "new" operator to create a new instance of this class.
140 : /// This function automatically chooses a correct implementation, depending on if
141 : /// integer ot floating point arithmetics are to be used.
142 : // static RateTransposer *newInstance();
143 :
144 : /// Returns the output buffer object
145 0 : FIFOSamplePipe *getOutput() { return &outputBuffer; };
146 :
147 : /// Returns the store buffer object
148 : // FIFOSamplePipe *getStore() { return &storeBuffer; };
149 :
150 : /// Return anti-alias filter object
151 : AAFilter *getAAFilter();
152 :
153 : /// Enables/disables the anti-alias filter. Zero to disable, nonzero to enable
154 : void enableAAFilter(bool newMode);
155 :
156 : /// Returns nonzero if anti-alias filter is enabled.
157 : bool isAAFilterEnabled() const;
158 :
159 : /// Sets new target rate. Normal rate = 1.0, smaller values represent slower
160 : /// rate, larger faster rates.
161 : virtual void setRate(float newRate);
162 :
163 : /// Sets the number of channels, 1 = mono, 2 = stereo
164 : void setChannels(int channels);
165 :
166 : /// Adds 'numSamples' pcs of samples from the 'samples' memory position into
167 : /// the input of the object.
168 : void putSamples(const SAMPLETYPE *samples, uint numSamples);
169 :
170 : /// Clears all the samples in the object
171 : void clear();
172 :
173 : /// Returns nonzero if there aren't any samples available for outputting.
174 : int isEmpty() const;
175 : };
176 :
177 : }
178 :
179 : #endif
|
