media/libsoundtouch/src/AAFilter.h@b8a032363ba2 (annotated)
media/libsoundtouch/src/AAFilter.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | //////////////////////////////////////////////////////////////////////////////// |
| michael@0 | 2 | /// |
| michael@0 | 3 | /// Sampled sound tempo changer/time stretch algorithm. Changes the sound tempo |
| michael@0 | 4 | /// while maintaining the original pitch by using a time domain WSOLA-like method |
| michael@0 | 5 | /// with several performance-increasing tweaks. |
| michael@0 | 6 | /// |
| michael@0 | 7 | /// Anti-alias filter is used to prevent folding of high frequencies when |
| michael@0 | 8 | /// transposing the sample rate with interpolation. |
| michael@0 | 9 | /// |
| michael@0 | 10 | /// Author : Copyright (c) Olli Parviainen |
| michael@0 | 11 | /// Author e-mail : oparviai 'at' iki.fi |
| michael@0 | 12 | /// SoundTouch WWW: http://www.surina.net/soundtouch |
| michael@0 | 13 | /// |
| michael@0 | 14 | //////////////////////////////////////////////////////////////////////////////// |
| michael@0 | 15 | // |
| michael@0 | 16 | // Last changed : $Date: 2014-01-07 13:41:23 -0600 (Tue, 07 Jan 2014) $ |
| michael@0 | 17 | // File revision : $Revision: 4 $ |
| michael@0 | 18 | // |
| michael@0 | 19 | // $Id: AAFilter.h 187 2014-01-07 19:41:23Z oparviai $ |
| michael@0 | 20 | // |
| michael@0 | 21 | //////////////////////////////////////////////////////////////////////////////// |
| michael@0 | 22 | // |
| michael@0 | 23 | // License : |
| michael@0 | 24 | // |
| michael@0 | 25 | // SoundTouch audio processing library |
| michael@0 | 26 | // Copyright (c) Olli Parviainen |
| michael@0 | 27 | // |
| michael@0 | 28 | // This library is free software; you can redistribute it and/or |
| michael@0 | 29 | // modify it under the terms of the GNU Lesser General Public |
| michael@0 | 30 | // License as published by the Free Software Foundation; either |
| michael@0 | 31 | // version 2.1 of the License, or (at your option) any later version. |
| michael@0 | 32 | // |
| michael@0 | 33 | // This library is distributed in the hope that it will be useful, |
| michael@0 | 34 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| michael@0 | 35 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| michael@0 | 36 | // Lesser General Public License for more details. |
| michael@0 | 37 | // |
| michael@0 | 38 | // You should have received a copy of the GNU Lesser General Public |
| michael@0 | 39 | // License along with this library; if not, write to the Free Software |
| michael@0 | 40 | // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| michael@0 | 41 | // |
| michael@0 | 42 | //////////////////////////////////////////////////////////////////////////////// |
| michael@0 | 43 | |
| michael@0 | 44 | #ifndef AAFilter_H |
| michael@0 | 45 | #define AAFilter_H |
| michael@0 | 46 | |
| michael@0 | 47 | #include "STTypes.h" |
| michael@0 | 48 | #include "FIFOSampleBuffer.h" |
| michael@0 | 49 | |
| michael@0 | 50 | namespace soundtouch |
| michael@0 | 51 | { |
| michael@0 | 52 | |
| michael@0 | 53 | class AAFilter |
| michael@0 | 54 | { |
| michael@0 | 55 | protected: |
| michael@0 | 56 | class FIRFilter *pFIR; |
| michael@0 | 57 | |
| michael@0 | 58 | /// Low-pass filter cut-off frequency, negative = invalid |
| michael@0 | 59 | double cutoffFreq; |
| michael@0 | 60 | |
| michael@0 | 61 | /// num of filter taps |
| michael@0 | 62 | uint length; |
| michael@0 | 63 | |
| michael@0 | 64 | /// Calculate the FIR coefficients realizing the given cutoff-frequency |
| michael@0 | 65 | void calculateCoeffs(); |
| michael@0 | 66 | public: |
| michael@0 | 67 | AAFilter(uint length); |
| michael@0 | 68 | |
| michael@0 | 69 | ~AAFilter(); |
| michael@0 | 70 | |
| michael@0 | 71 | /// Sets new anti-alias filter cut-off edge frequency, scaled to sampling |
| michael@0 | 72 | /// frequency (nyquist frequency = 0.5). The filter will cut off the |
| michael@0 | 73 | /// frequencies than that. |
| michael@0 | 74 | void setCutoffFreq(double newCutoffFreq); |
| michael@0 | 75 | |
| michael@0 | 76 | /// Sets number of FIR filter taps, i.e. ~filter complexity |
| michael@0 | 77 | void setLength(uint newLength); |
| michael@0 | 78 | |
| michael@0 | 79 | uint getLength() const; |
| michael@0 | 80 | |
| michael@0 | 81 | /// Applies the filter to the given sequence of samples. |
| michael@0 | 82 | /// Note : The amount of outputted samples is by value of 'filter length' |
| michael@0 | 83 | /// smaller than the amount of input samples. |
| michael@0 | 84 | uint evaluate(SAMPLETYPE *dest, |
| michael@0 | 85 | const SAMPLETYPE *src, |
| michael@0 | 86 | uint numSamples, |
| michael@0 | 87 | uint numChannels) const; |
| michael@0 | 88 | |
| michael@0 | 89 | /// Applies the filter to the given src & dest pipes, so that processed amount of |
| michael@0 | 90 | /// samples get removed from src, and produced amount added to dest |
| michael@0 | 91 | /// Note : The amount of outputted samples is by value of 'filter length' |
| michael@0 | 92 | /// smaller than the amount of input samples. |
| michael@0 | 93 | uint evaluate(FIFOSampleBuffer &dest, |
| michael@0 | 94 | FIFOSampleBuffer &src) const; |
| michael@0 | 95 | |
| michael@0 | 96 | }; |
| michael@0 | 97 | |
| michael@0 | 98 | } |
| michael@0 | 99 | |
| michael@0 | 100 | #endif |
