vrshoot
annotate libs/vorbis/scales.h @ 0:b2f14e535253
initial commit
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sat, 01 Feb 2014 19:58:19 +0200 |
| parents | |
| children |
| rev | line source |
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| nuclear@0 | 1 /******************************************************************** |
| nuclear@0 | 2 * * |
| nuclear@0 | 3 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * |
| nuclear@0 | 4 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * |
| nuclear@0 | 5 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * |
| nuclear@0 | 6 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * |
| nuclear@0 | 7 * * |
| nuclear@0 | 8 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 * |
| nuclear@0 | 9 * by the Xiph.Org Foundation http://www.xiph.org/ * |
| nuclear@0 | 10 * * |
| nuclear@0 | 11 ******************************************************************** |
| nuclear@0 | 12 |
| nuclear@0 | 13 function: linear scale -> dB, Bark and Mel scales |
| nuclear@0 | 14 last mod: $Id: scales.h 16227 2009-07-08 06:58:46Z xiphmont $ |
| nuclear@0 | 15 |
| nuclear@0 | 16 ********************************************************************/ |
| nuclear@0 | 17 |
| nuclear@0 | 18 #ifndef _V_SCALES_H_ |
| nuclear@0 | 19 #define _V_SCALES_H_ |
| nuclear@0 | 20 |
| nuclear@0 | 21 #include <math.h> |
| nuclear@0 | 22 #include "os.h" |
| nuclear@0 | 23 |
| nuclear@0 | 24 #ifdef _MSC_VER |
| nuclear@0 | 25 /* MS Visual Studio doesn't have C99 inline keyword. */ |
| nuclear@0 | 26 #define inline __inline |
| nuclear@0 | 27 #endif |
| nuclear@0 | 28 |
| nuclear@0 | 29 /* 20log10(x) */ |
| nuclear@0 | 30 #define VORBIS_IEEE_FLOAT32 1 |
| nuclear@0 | 31 #ifdef VORBIS_IEEE_FLOAT32 |
| nuclear@0 | 32 |
| nuclear@0 | 33 static inline float unitnorm(float x){ |
| nuclear@0 | 34 union { |
| nuclear@0 | 35 ogg_uint32_t i; |
| nuclear@0 | 36 float f; |
| nuclear@0 | 37 } ix; |
| nuclear@0 | 38 ix.f = x; |
| nuclear@0 | 39 ix.i = (ix.i & 0x80000000U) | (0x3f800000U); |
| nuclear@0 | 40 return ix.f; |
| nuclear@0 | 41 } |
| nuclear@0 | 42 |
| nuclear@0 | 43 /* Segher was off (too high) by ~ .3 decibel. Center the conversion correctly. */ |
| nuclear@0 | 44 static inline float todB(const float *x){ |
| nuclear@0 | 45 union { |
| nuclear@0 | 46 ogg_uint32_t i; |
| nuclear@0 | 47 float f; |
| nuclear@0 | 48 } ix; |
| nuclear@0 | 49 ix.f = *x; |
| nuclear@0 | 50 ix.i = ix.i&0x7fffffff; |
| nuclear@0 | 51 return (float)(ix.i * 7.17711438e-7f -764.6161886f); |
| nuclear@0 | 52 } |
| nuclear@0 | 53 |
| nuclear@0 | 54 #define todB_nn(x) todB(x) |
| nuclear@0 | 55 |
| nuclear@0 | 56 #else |
| nuclear@0 | 57 |
| nuclear@0 | 58 static float unitnorm(float x){ |
| nuclear@0 | 59 if(x<0)return(-1.f); |
| nuclear@0 | 60 return(1.f); |
| nuclear@0 | 61 } |
| nuclear@0 | 62 |
| nuclear@0 | 63 #define todB(x) (*(x)==0?-400.f:log(*(x)**(x))*4.34294480f) |
| nuclear@0 | 64 #define todB_nn(x) (*(x)==0.f?-400.f:log(*(x))*8.6858896f) |
| nuclear@0 | 65 |
| nuclear@0 | 66 #endif |
| nuclear@0 | 67 |
| nuclear@0 | 68 #define fromdB(x) (exp((x)*.11512925f)) |
| nuclear@0 | 69 |
| nuclear@0 | 70 /* The bark scale equations are approximations, since the original |
| nuclear@0 | 71 table was somewhat hand rolled. The below are chosen to have the |
| nuclear@0 | 72 best possible fit to the rolled tables, thus their somewhat odd |
| nuclear@0 | 73 appearance (these are more accurate and over a longer range than |
| nuclear@0 | 74 the oft-quoted bark equations found in the texts I have). The |
| nuclear@0 | 75 approximations are valid from 0 - 30kHz (nyquist) or so. |
| nuclear@0 | 76 |
| nuclear@0 | 77 all f in Hz, z in Bark */ |
| nuclear@0 | 78 |
| nuclear@0 | 79 #define toBARK(n) (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n)) |
| nuclear@0 | 80 #define fromBARK(z) (102.f*(z)-2.f*pow(z,2.f)+.4f*pow(z,3.f)+pow(1.46f,z)-1.f) |
| nuclear@0 | 81 #define toMEL(n) (log(1.f+(n)*.001f)*1442.695f) |
| nuclear@0 | 82 #define fromMEL(m) (1000.f*exp((m)/1442.695f)-1000.f) |
| nuclear@0 | 83 |
| nuclear@0 | 84 /* Frequency to octave. We arbitrarily declare 63.5 Hz to be octave |
| nuclear@0 | 85 0.0 */ |
| nuclear@0 | 86 |
| nuclear@0 | 87 #define toOC(n) (log(n)*1.442695f-5.965784f) |
| nuclear@0 | 88 #define fromOC(o) (exp(((o)+5.965784f)*.693147f)) |
| nuclear@0 | 89 |
| nuclear@0 | 90 #endif |