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Add a noise generator (Lua DSP)

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This commit is contained in:
Robin Gareus 2017-11-11 22:47:47 +01:00
parent 52aa9bf848
commit 93e32af9f4
3 changed files with 121 additions and 0 deletions
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28
libs/ardour/ardour/dsp_filter.h
View File

@ -310,5 +310,33 @@ namespace ARDOUR { namespace DSP {
fftwf_plan _fftplan;
};
class LIBARDOUR_API Generator {
public:
Generator ();
enum Type {
UniformWhiteNoise,
GaussianWhiteNoise,
PinkNoise,
};
void run (float *data, const uint32_t n_samples);
void set_type (Type t);
private:
uint32_t randi ();
float randf () { return (randi () / 1073741824.f) - 1.f; }
float grandf ();
Type _type;
uint32_t _rseed;
/* pink-noise */
float _b0, _b1, _b2, _b3, _b4, _b5, _b6;
/* gaussian white */
bool _pass;
float _rn;
};
} } /* namespace */
#endif

82
libs/ardour/dsp_filter.cc
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@ -425,3 +425,85 @@ FFTSpectrum::power_at_bin (const uint32_t b, const float norm) const {
const float a = _fft_power[b] * norm;
return a > 1e-12 ? 10.0 * fast_log10 (a) : -INFINITY;
}
Generator::Generator ()
: _type (UniformWhiteNoise)
, _rseed (1)
{
set_type (UniformWhiteNoise);
}
void
Generator::set_type (Generator::Type t) {
_type = t;
_b0 = _b1 = _b2 = _b3 = _b4 = _b5 = _b6 = 0;
_pass = false;
_rn = 0;
}
void
Generator::run (float *data, const uint32_t n_samples)
{
switch (_type) {
default:
case UniformWhiteNoise:
for (uint32_t i = 0; i < n_samples; ++i) {
data[i] = randf();
}
break;
case GaussianWhiteNoise:
for (uint32_t i = 0 ; i < n_samples; ++i) {
data[i] = 0.7079f * grandf();
}
break;
case PinkNoise:
for (uint32_t i = 0 ; i < n_samples; ++i) {
const float white = .39572f * randf ();
_b0 = .99886f * _b0 + white * .0555179f;
_b1 = .99332f * _b1 + white * .0750759f;
_b2 = .96900f * _b2 + white * .1538520f;
_b3 = .86650f * _b3 + white * .3104856f;
_b4 = .55000f * _b4 + white * .5329522f;
_b5 = -.7616f * _b5 - white * .0168980f;
data[i] = _b0 + _b1 + _b2 + _b3 + _b4 + _b5 + _b6 + white * 0.5362f;
_b6 = white * 0.115926f;
}
break;
}
}
inline uint32_t
Generator::randi ()
{
// 31bit Park-Miller-Carta Pseudo-Random Number Generator
uint32_t hi, lo;
lo = 16807 * (_rseed & 0xffff);
hi = 16807 * (_rseed >> 16);
lo += (hi & 0x7fff) << 16;
lo += hi >> 15;
lo = (lo & 0x7fffffff) + (lo >> 31);
return (_rseed = lo);
}
inline float
Generator::grandf ()
{
float x1, x2, r;
if (_pass) {
_pass = false;
return _rn;
}
do {
x1 = randf ();
x2 = randf ();
r = x1 * x1 + x2 * x2;
} while ((r >= 1.0f) || (r < 1e-22f));
r = sqrtf (-2.f * logf (r) / r);
_pass = true;
_rn = r * x2;
return r * x1;
}

11
libs/ardour/luabindings.cc
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@ -2353,6 +2353,11 @@ LuaBindings::common (lua_State* L)
.addFunction ("power_at_bin", &DSP::FFTSpectrum::power_at_bin)
.addFunction ("freq_at_bin", &DSP::FFTSpectrum::freq_at_bin)
.endClass ()
.beginClass <DSP::Generator> ("Generator")
.addVoidConstructor ()
.addFunction ("run", &DSP::Generator::run)
.addFunction ("set_type", &DSP::Generator::set_type)
.endClass ()
/* DSP enums */
.beginNamespace ("BiquadType")
@ -2367,6 +2372,12 @@ LuaBindings::common (lua_State* L)
.addConst ("HighShelf", ARDOUR::DSP::Biquad::HighShelf)
.endNamespace ()
.beginNamespace ("NoiseType")
.addConst ("UniformWhiteNoise", ARDOUR::DSP::Generator::UniformWhiteNoise)
.addConst ("GaussianWhiteNoise", ARDOUR::DSP::Generator::GaussianWhiteNoise)
.addConst ("PinkNoise", ARDOUR::DSP::Generator::PinkNoise)
.endNamespace ()
.beginClass <DSP::DspShm> ("DspShm")
.addConstructor<void (*) (size_t)> ()
.addFunction ("allocate", &DSP::DspShm::allocate)