Mercurial > hg > svcore
view data/model/WaveformOversampler.h @ 1577:50fe6d6a5ef0
Merge from branch spectrogramparam
author | Chris Cannam |
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date | Wed, 14 Nov 2018 14:21:53 +0000 |
parents | eb10ed56d5a4 |
children | 074b860a7828 |
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See the file COPYING included with this distribution for more information. */ #ifndef SV_WAVEFORM_OVERSAMPLER_H #define SV_WAVEFORM_OVERSAMPLER_H #include "base/BaseTypes.h" class DenseTimeValueModel; /** Oversample the sample data from a DenseTimeValueModel by an * integer factor, on the assumption that the model represents * audio. Oversampling is carried out using a windowed sinc filter * for a fixed 8x ratio with further linear interpolation to handle * other ratios. The aim is not to provide the "best-sounding" * interpolation, but to provide accurate and predictable projections * of the theoretical waveform shape for display rendering without * leaving decisions about interpolation up to a resampler library. */ class WaveformOversampler { public: /** Return an oversampled version of the audio data from the given * source sample range. Will query sufficient source audio before * and after the requested range (where available) to ensure an * accurate-looking result after filtering. The returned vector * will have sourceFrameCount * oversampleBy samples, except when * truncated because the end of the model was reached. */ static floatvec_t getOversampledData(const DenseTimeValueModel *source, int channel, sv_frame_t sourceStartFrame, sv_frame_t sourceFrameCount, int oversampleBy); private: static floatvec_t getFixedRatioData(const DenseTimeValueModel *source, int channel, sv_frame_t sourceStartFrame, sv_frame_t sourceFrameCount); static int m_filterRatio; static floatvec_t m_filter; }; #endif