68 lines
2.3 KiB
C++
68 lines
2.3 KiB
C++
/* Copyright (C) 2015-2022 Sergey V. Mikayev
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef SRCTOOLS_FIR_RESAMPLER_H
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#define SRCTOOLS_FIR_RESAMPLER_H
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#include "ResamplerStage.h"
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namespace SRCTools {
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typedef FloatSample FIRCoefficient;
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static const unsigned int FIR_INTERPOLATOR_CHANNEL_COUNT = 2;
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class FIRResampler : public ResamplerStage {
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public:
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FIRResampler(const unsigned int upsampleFactor, const double downsampleFactor, const FIRCoefficient kernel[], const unsigned int kernelLength);
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~FIRResampler();
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void process(const FloatSample *&inSamples, unsigned int &inLength, FloatSample *&outSamples, unsigned int &outLength);
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unsigned int estimateInLength(const unsigned int outLength) const;
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private:
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const struct Constants {
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// Filter coefficients
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const FIRCoefficient *taps;
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// Indicates whether to interpolate filter taps
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bool usePhaseInterpolation;
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// Size of array of filter coefficients
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unsigned int numberOfTaps;
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// Upsampling factor
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unsigned int numberOfPhases;
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// Downsampling factor
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double phaseIncrement;
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// Index of last delay line element, generally greater than numberOfTaps to form a proper binary mask
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unsigned int delayLineMask;
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// Delay line
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FloatSample(*ringBuffer)[FIR_INTERPOLATOR_CHANNEL_COUNT];
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Constants(const unsigned int upsampleFactor, const double downsampleFactor, const FIRCoefficient kernel[], const unsigned int kernelLength);
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} constants;
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// Index of current sample in delay line
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unsigned int ringBufferPosition;
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// Current phase
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double phase;
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bool needNextInSample() const;
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void addInSamples(const FloatSample *&inSamples);
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void getOutSamplesStereo(FloatSample *&outSamples);
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}; // class FIRResampler
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} // namespace SRCTools
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#endif // SRCTOOLS_FIR_RESAMPLER_H
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