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keep DSP state variables finite.

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This commit is contained in:
Robin Gareus 2016-05-21 12:52:02 +02:00
parent e4a5c3609d
commit 53c188beb3
2 changed files with 18 additions and 4 deletions
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4
libs/ardour/ardour/dsp_filter.h
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@ -229,9 +229,9 @@ namespace ARDOUR { namespace DSP {
*/
void compute (Type t, double freq, double Q, double gain);
/** filter transfer function (for spectrum visualization)
/** filter transfer function (filter response for spectrum visualization)
* @param freq frequency
* @return gain at given frequency in dB
* @return gain at given frequency in dB (clamped to -120..+120)
*/
float dB_at_freq (float freq) const;

18
libs/ardour/dsp_filter.cc
View File

@ -17,11 +17,19 @@
*
*/
#include <algorithm>
#include <stdlib.h>
#include <math.h>
#include <cmath>
#include "ardour/dB.h"
#include "ardour/dsp_filter.h"
#ifdef COMPILER_MSVC
#include <float.h>
#define isfinite_local(val) (bool)_finite((double)val)
#else
#define isfinite_local std::isfinite
#endif
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
@ -89,6 +97,7 @@ LowPass::proc (float *data, const uint32_t n_samples)
z = data[i];
}
_z = z;
if (!isfinite_local (_z)) { _z = 0; }
}
void
@ -140,6 +149,9 @@ BiQuad::run (float *data, const uint32_t n_samples)
_z2 = _b2 * xn - _a2 * z;
data[i] = z;
}
if (!isfinite_local (_z1)) { _z1 = 0; }
if (!isfinite_local (_z2)) { _z2 = 0; }
}
void
@ -273,5 +285,7 @@ BiQuad::dB_at_freq (float freq) const
const float d = D * s1;
#define SQUARE(x) ( (x) * (x) )
return 20.f * log10f (sqrtf ((SQUARE(a) + SQUARE(b)) * (SQUARE(c) + SQUARE(d))) / (SQUARE(c) + SQUARE(d)));
float rv = 20.f * log10f (sqrtf ((SQUARE(a) + SQUARE(b)) * (SQUARE(c) + SQUARE(d))) / (SQUARE(c) + SQUARE(d)));
if (!isfinite_local (rv)) { rv = 0; }
return std::min (120.f, std::max(-120.f, rv));
}