media/libsoundtouch/src/AAFilter.h@97036ab72558
media/libsoundtouch/src/AAFilter.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
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: 2014-01-07 13:41:23 -0600 (Tue, 07 Jan 2014) $
17 // File revision : $Revision: 4 $
18 //
19 // $Id: AAFilter.h 187 2014-01-07 19:41:23Z 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 ////////////////////////////////////////////////////////////////////////////////
44 #ifndef AAFilter_H
45 #define AAFilter_H
47 #include "STTypes.h"
48 #include "FIFOSampleBuffer.h"
50 namespace soundtouch
51 {
53 class AAFilter
54 {
55 protected:
56 class FIRFilter *pFIR;
58 /// Low-pass filter cut-off frequency, negative = invalid
59 double cutoffFreq;
61 /// num of filter taps
62 uint length;
64 /// Calculate the FIR coefficients realizing the given cutoff-frequency
65 void calculateCoeffs();
66 public:
67 AAFilter(uint length);
69 ~AAFilter();
71 /// Sets new anti-alias filter cut-off edge frequency, scaled to sampling
72 /// frequency (nyquist frequency = 0.5). The filter will cut off the
73 /// frequencies than that.
74 void setCutoffFreq(double newCutoffFreq);
76 /// Sets number of FIR filter taps, i.e. ~filter complexity
77 void setLength(uint newLength);
79 uint getLength() const;
81 /// Applies the filter to the given sequence of samples.
82 /// Note : The amount of outputted samples is by value of 'filter length'
83 /// smaller than the amount of input samples.
84 uint evaluate(SAMPLETYPE *dest,
85 const SAMPLETYPE *src,
86 uint numSamples,
87 uint numChannels) const;
89 /// Applies the filter to the given src & dest pipes, so that processed amount of
90 /// samples get removed from src, and produced amount added to dest
91 /// Note : The amount of outputted samples is by value of 'filter length'
92 /// smaller than the amount of input samples.
93 uint evaluate(FIFOSampleBuffer &dest,
94 FIFOSampleBuffer &src) const;
96 };
98 }
100 #endif
