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1 //
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2 // FIRFilter.cpp
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3 // Tempogram
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4 //
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5 // Created by Carl Bussey on 25/06/2014.
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6 // Copyright (c) 2014 Carl Bussey. All rights reserved.
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7 //
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8
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9 #include "FIRFilter.h"
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10
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11 using namespace std;
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12 using Vamp::FFT;
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13
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14 FIRFilter::FIRFilter(const unsigned int lengthInput, const unsigned int numberOfCoefficients) :
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15 _lengthInput(lengthInput),
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16 _numberOfCoefficients(numberOfCoefficients),
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17 fftInput(NULL),
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18 fftCoefficients(NULL),
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19 fftReal1(NULL),
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20 fftImag1(NULL),
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21 fftReal2(NULL),
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22 fftImag2(NULL),
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23 fftFilteredReal(NULL),
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24 fftFilteredImag(NULL),
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25 fftOutputReal(NULL),
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26 fftOutputImag(NULL)
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27 {
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28 initialise();
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29 }
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30
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31 FIRFilter::~FIRFilter()
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32 {
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33 cleanup();
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34 }
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35
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36 void
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37 FIRFilter::initialise()
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38 {
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39 _lengthFIRFFT = pow(2,(ceil(log2(_lengthInput+_numberOfCoefficients-1))));
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40
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41 fftInput = new double[_lengthFIRFFT];
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42 fftCoefficients = new double[_lengthFIRFFT];
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43 fftReal1 = new double[_lengthFIRFFT];
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44 fftImag1 = new double[_lengthFIRFFT];
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45 fftReal2 = new double[_lengthFIRFFT];
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46 fftImag2 = new double[_lengthFIRFFT];
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47 fftFilteredReal = new double[_lengthFIRFFT];
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48 fftFilteredImag = new double[_lengthFIRFFT];
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49 fftOutputReal = new double[_lengthFIRFFT];
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50 fftOutputImag = new double[_lengthFIRFFT];
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51
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52 for(int i = 0; i < _lengthFIRFFT; i++){
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53 fftInput[i] = fftCoefficients[i] = fftReal1[i] = fftImag1[i] = fftReal2[i] = fftImag2[i] = fftFilteredReal[i] = fftFilteredImag[i] = fftOutputReal[i] = fftOutputImag[i] = 0.0;
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54 }
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55 }
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56
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57 void
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58 FIRFilter::process(const float* input, const float* coefficients, float* output)
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59 {
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60 for(int i = 0; i < _lengthFIRFFT; i++){
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61 fftInput[i] = i < _lengthInput ? input[i] : 0.0;
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62 fftCoefficients[i] = i < _numberOfCoefficients ? coefficients[i] : 0.0;
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63 }
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64
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65 FFT::forward(_lengthFIRFFT, fftInput, NULL, fftReal1, fftImag1);
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66 FFT::forward(_lengthFIRFFT, fftCoefficients, NULL, fftReal2, fftImag2);
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67
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68 for (int i = 0; i < _lengthFIRFFT; i++){
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69 fftFilteredReal[i] = (fftReal1[i] * fftReal2[i]) - (fftImag1[i] * fftImag2[i]);
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70 fftFilteredImag[i] = (fftReal1[i] * fftImag2[i]) + (fftReal2[i] * fftImag1[i]);
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71 }
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72 FFT::inverse(_lengthFIRFFT, fftFilteredReal, fftFilteredImag, fftOutputReal, fftOutputImag);
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73
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74 for (int i = 0; i < _lengthInput; i++){
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75 output[i] = fftOutputReal[i];
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76 }
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77 }
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78
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79 void
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80 FIRFilter::cleanup()
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81 {
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82 delete []fftInput;
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83 delete []fftCoefficients;
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84 delete []fftReal1;
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85 delete []fftImag1;
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86 delete []fftReal2;
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87 delete []fftImag2;
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88 delete []fftFilteredReal;
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89 delete []fftFilteredImag;
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90 delete []fftOutputReal;
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91 delete []fftOutputImag;
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92 fftInput = fftCoefficients = fftReal1 = fftImag1 = fftReal2 = fftImag2 = fftFilteredReal = fftFilteredImag = fftOutputReal = fftOutputImag = NULL;
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93 } |
