annotate FIRFilter.cpp @ 47:cb79f27f0748

Clamp cyclic tempogram min and max BPM to the BPM equivalents of the actual underlying min and max tempogram bins, rather than the "input" min and max BPM (fixed root cause of #1054)

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
   Vamp Tempogram Plugin
   Carl Bussey, Centre for Digital Music, Queen Mary University of London
   Copyright 2014 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.
*/

#include "FIRFilter.h"

using namespace std;
using Vamp::FFT;

FIRFilter::FIRFilter(const size_t &lengthInput, const size_t &numberOfCoefficients) :
    m_lengthInput(lengthInput),
    m_numberOfCoefficients(numberOfCoefficients),
    m_pFftInput(0),
    m_pFftCoefficients(0),
    m_pFftReal1(0),
    m_pFftImag1(0),
    m_pFftReal2(0),
    m_pFftImag2(0),
    m_pFftFilteredReal(0),
    m_pFftFilteredImag(0),
    m_pFftOutputReal(0),
    m_pFftOutputImag(0)
{
    initialise();
}

FIRFilter::~FIRFilter()
{
    cleanup();
}

//allocate memory
void
FIRFilter::initialise()
{
    //next power of 2
    m_lengthFIRFFT = pow(2,(ceil(log2(m_lengthInput+m_numberOfCoefficients-1))));
    
    m_pFftInput = new double[m_lengthFIRFFT];
    m_pFftCoefficients = new double[m_lengthFIRFFT];
    m_pFftReal1 = new double[m_lengthFIRFFT];
    m_pFftImag1 = new double[m_lengthFIRFFT];
    m_pFftReal2 = new double[m_lengthFIRFFT];
    m_pFftImag2 = new double[m_lengthFIRFFT];
    m_pFftFilteredReal = new double[m_lengthFIRFFT];
    m_pFftFilteredImag = new double[m_lengthFIRFFT];
    m_pFftOutputReal = new double[m_lengthFIRFFT];
    m_pFftOutputImag = new double[m_lengthFIRFFT];
    
    for(int i = 0; i < (int)m_lengthFIRFFT; i++){
        m_pFftInput[i] = m_pFftCoefficients[i] = m_pFftReal1[i] = m_pFftImag1[i] = m_pFftReal2[i] = m_pFftImag2[i] = m_pFftFilteredReal[i] = m_pFftFilteredImag[i] = m_pFftOutputReal[i] = m_pFftOutputImag[i] = 0.0;
    }
}

void
FIRFilter::process(const float* pInput, const float* pCoefficients, float* pOutput, OutputTypeArgument outputType)
{
    
    //Copy to same length FFT buffers
    for(int i = 0; i < (int)m_lengthFIRFFT; i++){
        m_pFftInput[i] = i < (int)m_lengthInput ? pInput[i] : 0.0;
        m_pFftCoefficients[i] = i < (int)m_numberOfCoefficients ? pCoefficients[i] : 0.0;
    }
    
    FFT::forward(m_lengthFIRFFT, m_pFftInput, 0, m_pFftReal1, m_pFftImag1);
    FFT::forward(m_lengthFIRFFT, m_pFftCoefficients, 0, m_pFftReal2, m_pFftImag2);
    
    //Multiply FFT coefficients. Multiplication in freq domain is convolution in time domain.
    for (int i = 0; i < (int)m_lengthFIRFFT; i++){
        m_pFftFilteredReal[i] = (m_pFftReal1[i] * m_pFftReal2[i]) - (m_pFftImag1[i] * m_pFftImag2[i]);
        m_pFftFilteredImag[i] = (m_pFftReal1[i] * m_pFftImag2[i]) + (m_pFftReal2[i] * m_pFftImag1[i]);
    }
    
    FFT::inverse(m_lengthFIRFFT, m_pFftFilteredReal, m_pFftFilteredImag, m_pFftOutputReal, m_pFftOutputImag);
    
    //copy to output
    int offset = 0;
    int outputLength = m_lengthInput;
    if (outputType == all) outputLength = m_lengthInput+m_numberOfCoefficients-1;
    else if (outputType == middle) offset = floor(m_numberOfCoefficients/2.0f);
    else if (outputType != first) cerr << "FIRFilter::process(params) - " << outputType << " is not a valid argument. outputType is set to first." << endl;
    
    for (int i = 0; i < outputLength; i++){
        pOutput[i] = m_pFftOutputReal[i + offset];
    }
}

//remove memory allocations
void
FIRFilter::cleanup()
{
    delete []m_pFftInput;
    delete []m_pFftCoefficients;
    delete []m_pFftReal1;
    delete []m_pFftImag1;
    delete []m_pFftReal2;
    delete []m_pFftImag2;
    delete []m_pFftFilteredReal;
    delete []m_pFftFilteredImag;
    delete []m_pFftOutputReal;
    delete []m_pFftOutputImag;
    m_pFftInput = m_pFftCoefficients = m_pFftReal1 = m_pFftImag1 = m_pFftReal2 = m_pFftImag2 = m_pFftFilteredReal = m_pFftFilteredImag = m_pFftOutputReal = m_pFftOutputImag = 0;
}