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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
QM DSP Library
Centre for Digital Music, Queen Mary, University of London.
This file 2005-2006 Christian Landone.
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 DECIMATOR_H
#define DECIMATOR_H
/**
* Decimator carries out a fast downsample by a power-of-two
* factor. Only a limited number of factors are supported, from two to
* whatever getHighestSupportedFactor() returns. This is much faster
* than Resampler but has a worse signal-noise ratio.
*/
class Decimator
{
public:
/**
* Construct a Decimator to operate on input blocks of length
* inLength, with decimation factor decFactor. inLength should be
* a multiple of decFactor. Output blocks will be of length
* inLength / decFactor.
*
* decFactor must be a power of two. The highest supported factor
* is obtained through getHighestSupportedFactor(); for higher
* factors, you will need to chain more than one decimator.
*/
Decimator( unsigned int inLength, unsigned int decFactor );
virtual ~Decimator();
/**
* Process inLength samples (as supplied to constructor) from src
* and write inLength / decFactor samples to dst. Note that src
* and dst may be the same or overlap (an intermediate buffer is
* used).
*/
void process( const double* src, double* dst );
/**
* Process inLength samples (as supplied to constructor) from src
* and write inLength / decFactor samples to dst. Note that src
* and dst may be the same or overlap (an intermediate buffer is
* used).
*/
void process( const float* src, float* dst );
int getFactor() const { return m_decFactor; }
static int getHighestSupportedFactor() { return 8; }
void resetFilter();
private:
void deInitialise();
void initialise( unsigned int inLength, unsigned int decFactor );
void doAntiAlias( const double* src, double* dst, unsigned int length );
void doAntiAlias( const float* src, double* dst, unsigned int length );
unsigned int m_inputLength;
unsigned int m_outputLength;
unsigned int m_decFactor;
double Input;
double Output ;
double o1,o2,o3,o4,o5,o6,o7;
double a[ 9 ];
double b[ 9 ];
double* decBuffer;
};
#endif //
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