fuchsia / third_party / android / platform / external / aac / 5877c3e9599ad39e397dcfd0213d88905d192a78 / . / libFDK / src / FDK_trigFcts.cpp

/* ----------------------------------------------------------------------------- | |

Software License for The Fraunhofer FDK AAC Codec Library for Android | |

© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten | |

Forschung e.V. All rights reserved. | |

1. INTRODUCTION | |

The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software | |

that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding | |

scheme for digital audio. This FDK AAC Codec software is intended to be used on | |

a wide variety of Android devices. | |

AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient | |

general perceptual audio codecs. AAC-ELD is considered the best-performing | |

full-bandwidth communications codec by independent studies and is widely | |

deployed. AAC has been standardized by ISO and IEC as part of the MPEG | |

specifications. | |

Patent licenses for necessary patent claims for the FDK AAC Codec (including | |

those of Fraunhofer) may be obtained through Via Licensing | |

(www.vialicensing.com) or through the respective patent owners individually for | |

the purpose of encoding or decoding bit streams in products that are compliant | |

with the ISO/IEC MPEG audio standards. Please note that most manufacturers of | |

Android devices already license these patent claims through Via Licensing or | |

directly from the patent owners, and therefore FDK AAC Codec software may | |

already be covered under those patent licenses when it is used for those | |

licensed purposes only. | |

Commercially-licensed AAC software libraries, including floating-point versions | |

with enhanced sound quality, are also available from Fraunhofer. Users are | |

encouraged to check the Fraunhofer website for additional applications | |

information and documentation. | |

2. COPYRIGHT LICENSE | |

Redistribution and use in source and binary forms, with or without modification, | |

are permitted without payment of copyright license fees provided that you | |

satisfy the following conditions: | |

You must retain the complete text of this software license in redistributions of | |

the FDK AAC Codec or your modifications thereto in source code form. | |

You must retain the complete text of this software license in the documentation | |

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The name of Fraunhofer may not be used to endorse or promote products derived | |

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You may not charge copyright license fees for anyone to use, copy or distribute | |

the FDK AAC Codec software or your modifications thereto. | |

Your modified versions of the FDK AAC Codec must carry prominent notices stating | |

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of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android" | |

must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK | |

AAC Codec Library for Android." | |

3. NO PATENT LICENSE | |

NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without | |

limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE. | |

Fraunhofer provides no warranty of patent non-infringement with respect to this | |

software. | |

You may use this FDK AAC Codec software or modifications thereto only for | |

purposes that are authorized by appropriate patent licenses. | |

4. DISCLAIMER | |

This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright | |

holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, | |

including but not limited to the implied warranties of merchantability and | |

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5. CONTACT INFORMATION | |

Fraunhofer Institute for Integrated Circuits IIS | |

Attention: Audio and Multimedia Departments - FDK AAC LL | |

Am Wolfsmantel 33 | |

91058 Erlangen, Germany | |

www.iis.fraunhofer.de/amm | |

amm-info@iis.fraunhofer.de | |

----------------------------------------------------------------------------- */ | |

/******************* Library for basic calculation routines ******************** | |

Author(s): Haricharan Lakshman, Manuel Jander | |

Description: Trigonometric functions fixed point fractional implementation. | |

*******************************************************************************/ | |

#include "FDK_trigFcts.h" | |

#include "fixpoint_math.h" | |

#define IMPROVE_ATAN2_ACCURACY 1 /* 0 --> 59 dB SNR 1 --> 65 dB SNR */ | |

#define MINSFTAB 7 | |

#define MAXSFTAB 25 | |

#if IMPROVE_ATAN2_ACCURACY | |

static const FIXP_DBL f_atan_expand_range[MAXSFTAB - (MINSFTAB - 1)] = { | |

/***************************************************************************** | |

* | |

* Table holds fixp_atan() output values which are outside of input range | |

* of fixp_atan() to improve SNR of fixp_atan2(). | |

* | |

* This Table might also be used in fixp_atan() so there a wider input | |

* range can be covered, too. | |

* | |

*****************************************************************************/ | |

FL2FXCONST_DBL(7.775862990872099e-001), | |

FL2FXCONST_DBL(7.814919928673978e-001), | |

FL2FXCONST_DBL(7.834450483314648e-001), | |

FL2FXCONST_DBL(7.844216021392089e-001), | |

FL2FXCONST_DBL(7.849098823026687e-001), | |

FL2FXCONST_DBL(7.851540227918509e-001), | |

FL2FXCONST_DBL(7.852760930873737e-001), | |

FL2FXCONST_DBL(7.853371282415015e-001), | |

FL2FXCONST_DBL(7.853676458193612e-001), | |

FL2FXCONST_DBL(7.853829046083906e-001), | |

FL2FXCONST_DBL(7.853905340029177e-001), | |

FL2FXCONST_DBL(7.853943487001828e-001), | |

FL2FXCONST_DBL(7.853962560488155e-001), | |

FL2FXCONST_DBL(7.853972097231319e-001), | |

FL2FXCONST_DBL(7.853976865602901e-001), | |

FL2FXCONST_DBL(7.853979249788692e-001), | |

FL2FXCONST_DBL(7.853980441881587e-001), | |

FL2FXCONST_DBL(7.853981037928035e-001), | |

FL2FXCONST_DBL(7.853981335951259e-001) | |

/* pi/4 = 0.785398163397448 = pi/2/ATO_SCALE */ | |

}; | |

#endif | |

FIXP_DBL fixp_atan2(FIXP_DBL y, FIXP_DBL x) { | |

FIXP_DBL q; | |

FIXP_DBL at; /* atan out */ | |

FIXP_DBL at2; /* atan2 out */ | |

FIXP_DBL ret = FL2FXCONST_DBL(-1.0f); | |

INT sf, sfo, stf; | |

/* --- division */ | |

if (y > FL2FXCONST_DBL(0.0f)) { | |

if (x > FL2FXCONST_DBL(0.0f)) { | |

q = fDivNormHighPrec(y, x, &sf); /* both pos. */ | |

} else if (x < FL2FXCONST_DBL(0.0f)) { | |

q = -fDivNormHighPrec(y, -x, &sf); /* x neg. */ | |

} else { /* (x == FL2FXCONST_DBL(0.0f)) */ | |

q = FL2FXCONST_DBL(+1.0f); /* y/x = pos/zero = +Inf */ | |

sf = 0; | |

} | |

} else if (y < FL2FXCONST_DBL(0.0f)) { | |

if (x > FL2FXCONST_DBL(0.0f)) { | |

q = -fDivNormHighPrec(-y, x, &sf); /* y neg. */ | |

} else if (x < FL2FXCONST_DBL(0.0f)) { | |

q = fDivNormHighPrec(-y, -x, &sf); /* both neg. */ | |

} else { /* (x == FL2FXCONST_DBL(0.0f)) */ | |

q = FL2FXCONST_DBL(-1.0f); /* y/x = neg/zero = -Inf */ | |

sf = 0; | |

} | |

} else { /* (y == FL2FXCONST_DBL(0.0f)) */ | |

q = FL2FXCONST_DBL(0.0f); | |

sf = 0; | |

} | |

sfo = sf; | |

/* --- atan() */ | |

if (sfo > ATI_SF) { | |

/* --- could not calc fixp_atan() here bec of input data out of range */ | |

/* ==> therefore give back boundary values */ | |

#if IMPROVE_ATAN2_ACCURACY | |

if (sfo > MAXSFTAB) sfo = MAXSFTAB; | |

#endif | |

if (q > FL2FXCONST_DBL(0.0f)) { | |

#if IMPROVE_ATAN2_ACCURACY | |

at = +f_atan_expand_range[sfo - ATI_SF - 1]; | |

#else | |

at = FL2FXCONST_DBL(+M_PI / 2 / ATO_SCALE); | |

#endif | |

} else if (q < FL2FXCONST_DBL(0.0f)) { | |

#if IMPROVE_ATAN2_ACCURACY | |

at = -f_atan_expand_range[sfo - ATI_SF - 1]; | |

#else | |

at = FL2FXCONST_DBL(-M_PI / 2 / ATO_SCALE); | |

#endif | |

} else { /* q == FL2FXCONST_DBL(0.0f) */ | |

at = FL2FXCONST_DBL(0.0f); | |

} | |

} else { | |

/* --- calc of fixp_atan() is possible; input data within range */ | |

/* ==> set q on fixed scale level as desired from fixp_atan() */ | |

stf = sfo - ATI_SF; | |

if (stf > 0) | |

q = q << (INT)fMin(stf, DFRACT_BITS - 1); | |

else | |

q = q >> (INT)fMin(-stf, DFRACT_BITS - 1); | |

at = fixp_atan(q); /* ATO_SF */ | |

} | |

// --- atan2() | |

at2 = at >> (AT2O_SF - ATO_SF); // now AT2O_SF for atan2 | |

if (x > FL2FXCONST_DBL(0.0f)) { | |

ret = at2; | |

} else if (x < FL2FXCONST_DBL(0.0f)) { | |

if (y >= FL2FXCONST_DBL(0.0f)) { | |

ret = at2 + FL2FXCONST_DBL(M_PI / AT2O_SCALE); | |

} else { | |

ret = at2 - FL2FXCONST_DBL(M_PI / AT2O_SCALE); | |

} | |

} else { | |

// x == 0 | |

if (y > FL2FXCONST_DBL(0.0f)) { | |

ret = FL2FXCONST_DBL(+M_PI / 2 / AT2O_SCALE); | |

} else if (y < FL2FXCONST_DBL(0.0f)) { | |

ret = FL2FXCONST_DBL(-M_PI / 2 / AT2O_SCALE); | |

} else if (y == FL2FXCONST_DBL(0.0f)) { | |

ret = FL2FXCONST_DBL(0.0f); | |

} | |

} | |

return ret; | |

} | |

FIXP_DBL fixp_atan(FIXP_DBL x) { | |

INT sign; | |

FIXP_DBL result, temp; | |

/* SNR of fixp_atan() = 56 dB */ | |

FIXP_DBL P281 = (FIXP_DBL)0x00013000; // 0.281 in q18 | |

FIXP_DBL ONEP571 = (FIXP_DBL)0x6487ef00; // 1.571 in q30 | |

if (x < FIXP_DBL(0)) { | |

sign = 1; | |

x = -x; | |

} else { | |

sign = 0; | |

} | |

FDK_ASSERT(FL2FXCONST_DBL(1.0 / 64.0) == Q(Q_ATANINP)); | |

/* calc of arctan */ | |

if (x < FL2FXCONST_DBL(1.0 / 64.0)) | |

/* | |

Chebyshev polynomial approximation of atan(x) | |

5th-order approximation: atan(x) = a1*x + a2*x^3 + a3*x^5 = x(a1 + x^2*(a2 + | |

a3*x^2)); a1 = 0.9949493661166540f, a2 = 0.2870606355326520f, a3 = | |

0.0780371764464410f; 7th-order approximation: atan(x) = a1*x + a2*x^3 + | |

a3*x^5 + a3*x^7 = x(a1 + x^2*(a2 + x^2*(a3 + a4*x^2))); a1 = | |

0.9991334482227801, a2 = -0.3205332923816640, a3 = 0.1449824901444650, a4 = | |

-0.0382544649702990; 7th-order approximation in use (the most accurate | |

solution) | |

*/ | |

{ | |

x <<= ATI_SF; | |

FIXP_DBL x2 = fPow2(x); | |

temp = fMultAddDiv2((FL2FXCONST_DBL(0.1449824901444650f) >> 1), x2, | |

FL2FXCONST_DBL(-0.0382544649702990)); | |

temp = fMultAddDiv2((FL2FXCONST_DBL(-0.3205332923816640f) >> 2), x2, temp); | |

temp = fMultAddDiv2((FL2FXCONST_DBL(0.9991334482227801f) >> 3), x2, temp); | |

result = fMult(x, (temp << 2)); | |

} else if (x < FL2FXCONST_DBL(1.28 / 64.0)) { | |

FIXP_DBL delta_fix; | |

FIXP_DBL PI_BY_4 = FL2FXCONST_DBL(3.1415926 / 4.0) >> 1; /* pi/4 in q30 */ | |

delta_fix = (x - FL2FXCONST_DBL(1.0 / 64.0)) << 5; /* q30 */ | |

result = PI_BY_4 + (delta_fix >> 1) - (fPow2Div2(delta_fix)); | |

} else { | |

/* Other approximation for |x| > 1.28 */ | |

INT res_e; | |

temp = fPow2Div2(x); /* q25 * q25 - (DFRACT_BITS-1) - 1 = q18 */ | |

temp = temp + P281; /* q18 + q18 = q18 */ | |

result = fDivNorm(x, temp, &res_e); | |

result = scaleValue(result, | |

(Q_ATANOUT - Q_ATANINP + 18 - DFRACT_BITS + 1) + res_e); | |

result = ONEP571 - result; /* q30 + q30 = q30 */ | |

} | |

if (sign) { | |

result = -result; | |

} | |

return (result); | |

} | |

#include "FDK_tools_rom.h" | |

FIXP_DBL fixp_cos(FIXP_DBL x, int scale) { | |

FIXP_DBL residual, error, sine, cosine; | |

residual = fixp_sin_cos_residual_inline(x, scale, &sine, &cosine); | |

error = fMult(sine, residual); | |

#ifdef SINETABLE_16BIT | |

return cosine - error; | |

#else | |

/* Undo downscaling by 1 which was done at fixp_sin_cos_residual_inline */ | |

return SATURATE_LEFT_SHIFT(cosine - error, 1, DFRACT_BITS); | |

#endif | |

} | |

FIXP_DBL fixp_sin(FIXP_DBL x, int scale) { | |

FIXP_DBL residual, error, sine, cosine; | |

residual = fixp_sin_cos_residual_inline(x, scale, &sine, &cosine); | |

error = fMult(cosine, residual); | |

#ifdef SINETABLE_16BIT | |

return sine + error; | |

#else | |

return SATURATE_LEFT_SHIFT(sine + error, 1, DFRACT_BITS); | |

#endif | |

} | |

void fixp_cos_sin(FIXP_DBL x, int scale, FIXP_DBL *cos, FIXP_DBL *sin) { | |

FIXP_DBL residual, error0, error1, sine, cosine; | |

residual = fixp_sin_cos_residual_inline(x, scale, &sine, &cosine); | |

error0 = fMult(sine, residual); | |

error1 = fMult(cosine, residual); | |

#ifdef SINETABLE_16BIT | |

*cos = cosine - error0; | |

*sin = sine + error1; | |

#else | |

*cos = SATURATE_LEFT_SHIFT(cosine - error0, 1, DFRACT_BITS); | |

*sin = SATURATE_LEFT_SHIFT(sine + error1, 1, DFRACT_BITS); | |

#endif | |

} |