1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libsoundtouch/src/AAFilter.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,100 @@
1.4 +////////////////////////////////////////////////////////////////////////////////
1.5 +///
1.6 +/// Sampled sound tempo changer/time stretch algorithm. Changes the sound tempo
1.7 +/// while maintaining the original pitch by using a time domain WSOLA-like method
1.8 +/// with several performance-increasing tweaks.
1.9 +///
1.10 +/// Anti-alias filter is used to prevent folding of high frequencies when
1.11 +/// transposing the sample rate with interpolation.
1.12 +///
1.13 +/// Author : Copyright (c) Olli Parviainen
1.14 +/// Author e-mail : oparviai 'at' iki.fi
1.15 +/// SoundTouch WWW: http://www.surina.net/soundtouch
1.16 +///
1.17 +////////////////////////////////////////////////////////////////////////////////
1.18 +//
1.19 +// Last changed : $Date: 2014-01-07 13:41:23 -0600 (Tue, 07 Jan 2014) $
1.20 +// File revision : $Revision: 4 $
1.21 +//
1.22 +// $Id: AAFilter.h 187 2014-01-07 19:41:23Z oparviai $
1.23 +//
1.24 +////////////////////////////////////////////////////////////////////////////////
1.25 +//
1.26 +// License :
1.27 +//
1.28 +// SoundTouch audio processing library
1.29 +// Copyright (c) Olli Parviainen
1.30 +//
1.31 +// This library is free software; you can redistribute it and/or
1.32 +// modify it under the terms of the GNU Lesser General Public
1.33 +// License as published by the Free Software Foundation; either
1.34 +// version 2.1 of the License, or (at your option) any later version.
1.35 +//
1.36 +// This library is distributed in the hope that it will be useful,
1.37 +// but WITHOUT ANY WARRANTY; without even the implied warranty of
1.38 +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
1.39 +// Lesser General Public License for more details.
1.40 +//
1.41 +// You should have received a copy of the GNU Lesser General Public
1.42 +// License along with this library; if not, write to the Free Software
1.43 +// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
1.44 +//
1.45 +////////////////////////////////////////////////////////////////////////////////
1.46 +
1.47 +#ifndef AAFilter_H
1.48 +#define AAFilter_H
1.49 +
1.50 +#include "STTypes.h"
1.51 +#include "FIFOSampleBuffer.h"
1.52 +
1.53 +namespace soundtouch
1.54 +{
1.55 +
1.56 +class AAFilter
1.57 +{
1.58 +protected:
1.59 + class FIRFilter *pFIR;
1.60 +
1.61 + /// Low-pass filter cut-off frequency, negative = invalid
1.62 + double cutoffFreq;
1.63 +
1.64 + /// num of filter taps
1.65 + uint length;
1.66 +
1.67 + /// Calculate the FIR coefficients realizing the given cutoff-frequency
1.68 + void calculateCoeffs();
1.69 +public:
1.70 + AAFilter(uint length);
1.71 +
1.72 + ~AAFilter();
1.73 +
1.74 + /// Sets new anti-alias filter cut-off edge frequency, scaled to sampling
1.75 + /// frequency (nyquist frequency = 0.5). The filter will cut off the
1.76 + /// frequencies than that.
1.77 + void setCutoffFreq(double newCutoffFreq);
1.78 +
1.79 + /// Sets number of FIR filter taps, i.e. ~filter complexity
1.80 + void setLength(uint newLength);
1.81 +
1.82 + uint getLength() const;
1.83 +
1.84 + /// Applies the filter to the given sequence of samples.
1.85 + /// Note : The amount of outputted samples is by value of 'filter length'
1.86 + /// smaller than the amount of input samples.
1.87 + uint evaluate(SAMPLETYPE *dest,
1.88 + const SAMPLETYPE *src,
1.89 + uint numSamples,
1.90 + uint numChannels) const;
1.91 +
1.92 + /// Applies the filter to the given src & dest pipes, so that processed amount of
1.93 + /// samples get removed from src, and produced amount added to dest
1.94 + /// Note : The amount of outputted samples is by value of 'filter length'
1.95 + /// smaller than the amount of input samples.
1.96 + uint evaluate(FIFOSampleBuffer &dest,
1.97 + FIFOSampleBuffer &src) const;
1.98 +
1.99 +};
1.100 +
1.101 +}
1.102 +
1.103 +#endif
