utils/makemhr/makemhr.h

   1 #ifndef MAKEMHR_H
   2 #define MAKEMHR_H
   3
   4 #include <vector>
   5 #include <complex>
   6
   7 #include "alcomplex.h"
   8 #include "polyphase_resampler.h"
   9
  10
  11 // The maximum path length used when processing filenames.
  12 #define MAX_PATH_LEN                 (256)
  13
  14 // The limit to the number of 'distances' listed in the data set definition.
  15 // Must be less than 256
  16 #define MAX_FD_COUNT                 (16)
  17
  18 // The limits to the number of 'elevations' listed in the data set definition.
  19 // Must be less than 256.
  20 #define MIN_EV_COUNT                 (5)
  21 #define MAX_EV_COUNT                 (181)
  22
  23 // The limits for each of the 'azimuths' listed in the data set definition.
  24 // Must be less than 256.
  25 #define MIN_AZ_COUNT                 (1)
  26 #define MAX_AZ_COUNT                 (255)
  27
  28 // The limits for the 'distance' from source to listener for each field in
  29 // the definition file.
  30 #define MIN_DISTANCE                 (0.05)
  31 #define MAX_DISTANCE                 (2.50)
  32
  33 // The limits for the sample 'rate' metric in the data set definition and for
  34 // resampling.
  35 #define MIN_RATE                     (32000)
  36 #define MAX_RATE                     (96000)
  37
  38 // The limits for the HRIR 'points' metric in the data set definition.
  39 #define MIN_POINTS                   (16)
  40 #define MAX_POINTS                   (8192)
  41
  42
  43 using uint = unsigned int;
  44
  45 /* Complex double type. */
  46 using complex_d = std::complex<double>;
  47
  48
  49 enum ChannelModeT : bool {
  50     CM_AllowStereo = false,
  51     CM_ForceMono = true
  52 };
  53
  54 // Sample and channel type enum values.
  55 enum SampleTypeT {
  56     ST_S16 = 0,
  57     ST_S24 = 1
  58 };
  59
  60 // Certain iterations rely on these integer enum values.
  61 enum ChannelTypeT {
  62     CT_NONE   = -1,
  63     CT_MONO   = 0,
  64     CT_STEREO = 1
  65 };
  66
  67 // Structured HRIR storage for stereo azimuth pairs, elevations, and fields.
  68 struct HrirAzT {
  69     double mAzimuth{0.0};
  70     uint mIndex{0u};
  71     double mDelays[2]{0.0, 0.0};
  72     double *mIrs[2]{nullptr, nullptr};
  73 };
  74
  75 struct HrirEvT {
  76     double mElevation{0.0};
  77     uint mAzCount{0u};
  78     HrirAzT *mAzs{nullptr};
  79 };
  80
  81 struct HrirFdT {
  82     double mDistance{0.0};
  83     uint mEvCount{0u};
  84     uint mEvStart{0u};
  85     HrirEvT *mEvs{nullptr};
  86 };
  87
  88 // The HRIR metrics and data set used when loading, processing, and storing
  89 // the resulting HRTF.
  90 struct HrirDataT {
  91     uint mIrRate{0u};
  92     SampleTypeT mSampleType{ST_S24};
  93     ChannelTypeT mChannelType{CT_NONE};
  94     uint mIrPoints{0u};
  95     uint mFftSize{0u};
  96     uint mIrSize{0u};
  97     double mRadius{0.0};
  98     uint mIrCount{0u};
  99
 100     std::vector<double> mHrirsBase;
 101     std::vector<HrirEvT> mEvsBase;
 102     std::vector<HrirAzT> mAzsBase;
 103
 104     std::vector<HrirFdT> mFds;
 105
 106     /* GCC warns when it tries to inline this. */
 107     ~HrirDataT();
 108 };
 109
 110
 111 int PrepareHrirData(const uint fdCount, const double (&distances)[MAX_FD_COUNT], const uint (&evCounts)[MAX_FD_COUNT], const uint azCounts[MAX_FD_COUNT * MAX_EV_COUNT], HrirDataT *hData);
 112 void MagnitudeResponse(const uint n, const complex_d *in, double *out);
 113
 114 // Performs a forward FFT.
 115 inline void FftForward(const uint n, complex_d *inout)
 116 { forward_fft(al::as_span(inout, n)); }
 117
 118 // Performs an inverse FFT.
 119 inline void FftInverse(const uint n, complex_d *inout)
 120 {
 121     inverse_fft(al::as_span(inout, n));
 122     double f{1.0 / n};
 123     for(uint i{0};i < n;i++)
 124         inout[i] *= f;
 125 }
 126
 127 // Performs linear interpolation.
 128 inline double Lerp(const double a, const double b, const double f)
 129 { return a + f * (b - a); }
 130
 131 #endif /* MAKEMHR_H */