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d9a291f641
Took the opportunity to undo the Godot changed made to the opus source. The opus module should eventually be built in its own environment to avoid polluting others with too many include dirs and defines. TODO: Fix the platform/ stuff for opus.
91 lines
2.8 KiB
C++
91 lines
2.8 KiB
C++
/********************************************************************
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* *
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* THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. *
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* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
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* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
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* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
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* *
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* THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 *
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* by the Xiph.Org Foundation http://www.xiph.org/ *
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* *
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********************************************************************
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function: linear scale -> dB, Bark and Mel scales
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last mod: $Id: scales.h 16227 2009-07-08 06:58:46Z xiphmont $
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********************************************************************/
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#ifndef _V_SCALES_H_
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#define _V_SCALES_H_
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#include <math.h>
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#include "os.h"
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#ifdef _MSC_VER
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/* MS Visual Studio doesn't have C99 inline keyword. */
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#define inline __inline
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#endif
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/* 20log10(x) */
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#define VORBIS_IEEE_FLOAT32 1
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#ifdef VORBIS_IEEE_FLOAT32
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static inline float unitnorm(float x){
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union {
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ogg_uint32_t i;
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float f;
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} ix;
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ix.f = x;
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ix.i = (ix.i & 0x80000000U) | (0x3f800000U);
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return ix.f;
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}
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/* Segher was off (too high) by ~ .3 decibel. Center the conversion correctly. */
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static inline float todB(const float *x){
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union {
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ogg_uint32_t i;
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float f;
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} ix;
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ix.f = *x;
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ix.i = ix.i&0x7fffffff;
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return (float)(ix.i * 7.17711438e-7f -764.6161886f);
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}
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#define todB_nn(x) todB(x)
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#else
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static float unitnorm(float x){
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if(x<0)return(-1.f);
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return(1.f);
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}
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#define todB(x) (*(x)==0?-400.f:log(*(x)**(x))*4.34294480f)
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#define todB_nn(x) (*(x)==0.f?-400.f:log(*(x))*8.6858896f)
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#endif
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#define fromdB(x) (exp((x)*.11512925f))
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/* The bark scale equations are approximations, since the original
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table was somewhat hand rolled. The below are chosen to have the
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best possible fit to the rolled tables, thus their somewhat odd
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appearance (these are more accurate and over a longer range than
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the oft-quoted bark equations found in the texts I have). The
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approximations are valid from 0 - 30kHz (nyquist) or so.
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all f in Hz, z in Bark */
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#define toBARK(n) (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n))
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#define fromBARK(z) (102.f*(z)-2.f*pow(z,2.f)+.4f*pow(z,3.f)+pow(1.46f,z)-1.f)
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#define toMEL(n) (log(1.f+(n)*.001f)*1442.695f)
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#define fromMEL(m) (1000.f*exp((m)/1442.695f)-1000.f)
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/* Frequency to octave. We arbitrarily declare 63.5 Hz to be octave
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0.0 */
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#define toOC(n) (log(n)*1.442695f-5.965784f)
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#define fromOC(o) (exp(((o)+5.965784f)*.693147f))
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#endif
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