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

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Revision 10 - (show annotations) (download)
Mon Sep 6 11:40:06 2010 UTC (9 years, 4 months ago) by william
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File size: 3075 byte(s)
exported r3113 from ./upstream/trunk
1 ////////////////////////////////////////////////////////////////////////////////
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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