/[pcsx2_0.9.7]/trunk/3rdparty/SoundTouch/AAFilter.h
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Annotation of /trunk/3rdparty/SoundTouch/AAFilter.h

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Mon Sep 6 18:15:43 2010 UTC (10 years, 11 months ago) by william
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re-initial commit of r3113
1 william 22 ////////////////////////////////////////////////////////////////////////////////
2     ///
3     /// Sampled sound tempo changer/time stretch algorithm. Changes the sound tempo
4     /// while maintaining the original pitch by using a time domain WSOLA-like method
5     /// with several performance-increasing tweaks.
6     ///
7     /// Anti-alias filter is used to prevent folding of high frequencies when
8     /// transposing the sample rate with interpolation.
9     ///
10     /// Author : Copyright (c) Olli Parviainen
11     /// Author e-mail : oparviai 'at' iki.fi
12     /// SoundTouch WWW: http://www.surina.net/soundtouch
13     ///
14     ////////////////////////////////////////////////////////////////////////////////
15     //
16     // Last changed : $Date: 2008-02-10 18:26:55 +0200 (Sun, 10 Feb 2008) $
17     // File revision : $Revision: 4 $
18     //
19     // $Id: AAFilter.h 11 2008-02-10 16:26:55Z oparviai $
20     //
21     ////////////////////////////////////////////////////////////////////////////////
22     //
23     // License :
24     //
25     // SoundTouch audio processing library
26     // Copyright (c) Olli Parviainen
27     //
28     // This library is free software; you can redistribute it and/or
29     // modify it under the terms of the GNU Lesser General Public
30     // License as published by the Free Software Foundation; either
31     // version 2.1 of the License, or (at your option) any later version.
32     //
33     // This library is distributed in the hope that it will be useful,
34     // but WITHOUT ANY WARRANTY; without even the implied warranty of
35     // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
36     // Lesser General Public License for more details.
37     //
38     // You should have received a copy of the GNU Lesser General Public
39     // License along with this library; if not, write to the Free Software
40     // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
41     //
42     ////////////////////////////////////////////////////////////////////////////////
43    
44     #ifndef AAFilter_H
45     #define AAFilter_H
46    
47     #include "STTypes.h"
48    
49     namespace soundtouch
50     {
51    
52     class AAFilter
53     {
54     protected:
55     class FIRFilter *pFIR;
56    
57     /// Low-pass filter cut-off frequency, negative = invalid
58     double cutoffFreq;
59    
60     /// num of filter taps
61     uint length;
62    
63     /// Calculate the FIR coefficients realizing the given cutoff-frequency
64     void calculateCoeffs();
65     public:
66     AAFilter(uint length);
67    
68     ~AAFilter();
69    
70     /// Sets new anti-alias filter cut-off edge frequency, scaled to sampling
71     /// frequency (nyquist frequency = 0.5). The filter will cut off the
72     /// frequencies than that.
73     void setCutoffFreq(double newCutoffFreq);
74    
75     /// Sets number of FIR filter taps, i.e. ~filter complexity
76     void setLength(uint newLength);
77    
78     uint getLength() const;
79    
80     /// Applies the filter to the given sequence of samples.
81     /// Note : The amount of outputted samples is by value of 'filter length'
82     /// smaller than the amount of input samples.
83     uint evaluate(SAMPLETYPE *dest,
84     const SAMPLETYPE *src,
85     uint numSamples,
86     uint numChannels) const;
87     };
88    
89     }
90    
91     #endif

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