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Diffstat (limited to 'audio/softsynth/mt32/srchelper/srctools/include/FIRResampler.h')
-rw-r--r-- | audio/softsynth/mt32/srchelper/srctools/include/FIRResampler.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/audio/softsynth/mt32/srchelper/srctools/include/FIRResampler.h b/audio/softsynth/mt32/srchelper/srctools/include/FIRResampler.h new file mode 100644 index 0000000000..2c5d69052a --- /dev/null +++ b/audio/softsynth/mt32/srchelper/srctools/include/FIRResampler.h @@ -0,0 +1,67 @@ +/* Copyright (C) 2015-2017 Sergey V. Mikayev + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 2.1 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef FIR_RESAMPLER_H +#define FIR_RESAMPLER_H + +#include "ResamplerStage.h" + +namespace SRCTools { + +typedef FloatSample FIRCoefficient; + +static const unsigned int FIR_INTERPOLATOR_CHANNEL_COUNT = 2; + +class FIRResampler : public ResamplerStage { +public: + FIRResampler(const unsigned int upsampleFactor, const double downsampleFactor, const FIRCoefficient kernel[], const unsigned int kernelLength); + ~FIRResampler(); + + void process(const FloatSample *&inSamples, unsigned int &inLength, FloatSample *&outSamples, unsigned int &outLength); + unsigned int estimateInLength(const unsigned int outLength) const; + +private: + const struct Constants { + // Filter coefficients + const FIRCoefficient *taps; + // Indicates whether to interpolate filter taps + bool usePhaseInterpolation; + // Size of array of filter coefficients + unsigned int numberOfTaps; + // Upsampling factor + unsigned int numberOfPhases; + // Downsampling factor + double phaseIncrement; + // Index of last delay line element, generally greater than numberOfTaps to form a proper binary mask + unsigned int delayLineMask; + // Delay line + FloatSample(*ringBuffer)[FIR_INTERPOLATOR_CHANNEL_COUNT]; + + Constants(const unsigned int upsampleFactor, const double downsampleFactor, const FIRCoefficient kernel[], const unsigned int kernelLength); + } constants; + // Index of current sample in delay line + unsigned int ringBufferPosition; + // Current phase + double phase; + + bool needNextInSample() const; + void addInSamples(const FloatSample *&inSamples); + void getOutSamplesStereo(FloatSample *&outSamples); +}; // class FIRResampler + +} // namespace SRCTools + +#endif // FIR_RESAMPLER_H |