Compressor.h (1406B)
1 /* 2 ZynAddSubFX - a software synthesizer 3 4 Compressor.h - simple audio compressor macros 5 Copyright (C) 2016-2021 Hans Petter Selasky 6 7 This program is free software; you can redistribute it and/or 8 modify it under the terms of the GNU General Public License 9 as published by the Free Software Foundation; either version 2 10 of the License, or (at your option) any later version. 11 */ 12 13 #ifndef _COMPRESSOR_H_ 14 #define _COMPRESSOR_H_ 15 16 static inline bool floatIsValid(float x) 17 { 18 const float r = x * 0.0f; 19 return (r == 0.0f); 20 } 21 22 static inline void stereoCompressor(const int div, float &peak, float &l, float &r) 23 { 24 /* 25 * Don't max the output range to avoid 26 * overflowing sample rate conversion and 27 * equalizer filters in the DSP's output 28 * path. Keep one 10th, 1dB, reserved. 29 */ 30 constexpr float limit = 1.0f - (1.0f / 10.0f); 31 32 /* sanity checks */ 33 if (!floatIsValid(peak)) 34 peak = 0.0f; 35 if (!floatIsValid(l)) 36 l = 0.0f; 37 if (!floatIsValid(r)) 38 r = 0.0f; 39 /* compute maximum */ 40 if (l < -peak) 41 peak = -l; 42 else if (l > peak) 43 peak = l; 44 if (r < -peak) 45 peak = -r; 46 else if (r > peak) 47 peak = r; 48 /* compressor */ 49 if (peak > limit) { 50 l /= peak; 51 r /= peak; 52 l *= limit; 53 r *= limit; 54 peak -= peak / div; 55 } 56 } 57 58 #endif /* _COMPRESSOR_H_ */