From 373dc625f82b47096893add42c4472e4a57ab7eb Mon Sep 17 00:00:00 2001 From: Aki Date: Wed, 9 Feb 2022 22:23:03 +0100 Subject: Moved third-party libraries to a separate subdirectory --- contrib/vorbis/lib/scales.h | 89 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 contrib/vorbis/lib/scales.h (limited to 'contrib/vorbis/lib/scales.h') diff --git a/contrib/vorbis/lib/scales.h b/contrib/vorbis/lib/scales.h new file mode 100644 index 0000000..18bc4e7 --- /dev/null +++ b/contrib/vorbis/lib/scales.h @@ -0,0 +1,89 @@ +/******************************************************************** + * * + * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * + * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * + * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * + * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * + * * + * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 * + * by the Xiph.Org Foundation http://www.xiph.org/ * + * * + ******************************************************************** + + function: linear scale -> dB, Bark and Mel scales + + ********************************************************************/ + +#ifndef _V_SCALES_H_ +#define _V_SCALES_H_ + +#include +#include "os.h" + +#ifdef _MSC_VER +/* MS Visual Studio doesn't have C99 inline keyword. */ +#define inline __inline +#endif + +/* 20log10(x) */ +#define VORBIS_IEEE_FLOAT32 1 +#ifdef VORBIS_IEEE_FLOAT32 + +static inline float unitnorm(float x){ + union { + ogg_uint32_t i; + float f; + } ix; + ix.f = x; + ix.i = (ix.i & 0x80000000U) | (0x3f800000U); + return ix.f; +} + +/* Segher was off (too high) by ~ .3 decibel. Center the conversion correctly. */ +static inline float todB(const float *x){ + union { + ogg_uint32_t i; + float f; + } ix; + ix.f = *x; + ix.i = ix.i&0x7fffffff; + return (float)(ix.i * 7.17711438e-7f -764.6161886f); +} + +#define todB_nn(x) todB(x) + +#else + +static float unitnorm(float x){ + if(x<0)return(-1.f); + return(1.f); +} + +#define todB(x) (*(x)==0?-400.f:log(*(x)**(x))*4.34294480f) +#define todB_nn(x) (*(x)==0.f?-400.f:log(*(x))*8.6858896f) + +#endif + +#define fromdB(x) (exp((x)*.11512925f)) + +/* The bark scale equations are approximations, since the original + table was somewhat hand rolled. The below are chosen to have the + best possible fit to the rolled tables, thus their somewhat odd + appearance (these are more accurate and over a longer range than + the oft-quoted bark equations found in the texts I have). The + approximations are valid from 0 - 30kHz (nyquist) or so. + + all f in Hz, z in Bark */ + +#define toBARK(n) (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n)) +#define fromBARK(z) (102.f*(z)-2.f*pow(z,2.f)+.4f*pow(z,3.f)+pow(1.46f,z)-1.f) +#define toMEL(n) (log(1.f+(n)*.001f)*1442.695f) +#define fromMEL(m) (1000.f*exp((m)/1442.695f)-1000.f) + +/* Frequency to octave. We arbitrarily declare 63.5 Hz to be octave + 0.0 */ + +#define toOC(n) (log(n)*1.442695f-5.965784f) +#define fromOC(o) (exp(((o)+5.965784f)*.693147f)) + +#endif -- cgit v1.1