/*
- Copyright (C) 2001 Paul Davis
+ Copyright (C) 2001 Paul Davis
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
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- $Id$
*/
#ifndef __ardour_dB_h__
#define __ardour_dB_h__
-#include <pbd/fastlog.h>
+#include <limits>
+#include "pbd/fastlog.h"
+
+#define GAIN_COEFF_ZERO 0.f
+#define GAIN_COEFF_SMALL 0.0000001f //-140dB
+#define GAIN_COEFF_UNITY 1.f
static inline float dB_to_coefficient (float dB) {
return dB > -318.8f ? pow (10.0f, dB * 0.05f) : 0.0f;
}
-static inline float coefficient_to_dB (float coeff) {
+static inline float fast_coefficient_to_dB (float coeff) {
return 20.0f * fast_log10 (coeff);
}
+static inline float accurate_coefficient_to_dB (float coeff) {
+ if (coeff < 1e-15) return -std::numeric_limits<float>::infinity();
+ return 20.0f * log10f (coeff);
+}
+
+static inline double dB_coeff_step(double max_coeff) {
+ const double max_db = lrint(accurate_coefficient_to_dB(max_coeff));
+ return 0.1 * (max_coeff / max_db);
+}
+
+extern double zero_db_as_fraction;
+
#endif /* __ardour_dB_h__ */