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- /*
- ZynAddSubFX - a software synthesizer
-
- Compressor.h - simple audio compressor macros
- Copyright (C) 2016 Hans Petter Selasky
-
- 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 the Free Software Foundation; either version 2
- of the License, or (at your option) any later version.
- */
-
- #ifndef _COMPRESSOR_H_
- #define _COMPRESSOR_H_
-
- #define floatIsValid(x) ({ \
- float __r = (x) * 0.0; \
- __r == 0.0 || __r == -0.0; \
- })
-
- #define stereoCompressor(div,pv,l,r) do { \
- /* \
- * Don't max the output range to avoid \
- * overflowing sample rate conversion and \
- * equalizer filters in the DSP's output \
- * path. Keep one 10th, 1dB, reserved. \
- */ \
- const float __limit = 1.0 - (1.0 / 10.0); \
- float __peak; \
- \
- /* sanity checks */ \
- __peak = (pv); \
- if (!floatIsValid(__peak)) \
- __peak = 0.0; \
- if (!floatIsValid(l)) \
- (l) = 0.0; \
- if (!floatIsValid(r)) \
- (r) = 0.0; \
- /* compute maximum */ \
- if ((l) < -__peak) \
- __peak = -(l); \
- else if ((l) > __peak) \
- __peak = (l); \
- if ((r) < -__peak) \
- __peak = -(r); \
- else if ((r) > __peak) \
- __peak = (r); \
- /* compressor */ \
- if (__peak > __limit) { \
- (l) /= __peak; \
- (r) /= __peak; \
- (l) *= __limit; \
- (r) *= __limit; \
- __peak -= __peak / (div); \
- } \
- (pv) = __peak; \
- } while (0)
-
- #endif /* _COMPRESSOR_H_ */
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