mirror of https://github.com/mstorsjo/fdk-aac.git
356 lines
14 KiB
C
356 lines
14 KiB
C
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/* -----------------------------------------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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© Copyright 1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
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All rights reserved.
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1. INTRODUCTION
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The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
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the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
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This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
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AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
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audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
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independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
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of the MPEG specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
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may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
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individually for the purpose of encoding or decoding bit streams in products that are compliant with
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the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
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these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
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software may already be covered under those patent licenses when it is used for those licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
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are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
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applications information and documentation.
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2. COPYRIGHT LICENSE
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Redistribution and use in source and binary forms, with or without modification, are permitted without
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payment of copyright license fees provided that you satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
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your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation and/or other materials
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provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
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You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
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modifications thereto to recipients of copies in binary form.
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The name of Fraunhofer may not be used to endorse or promote products derived from this library without
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prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
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software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
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and the date of any change. For modified versions of the FDK AAC Codec, the term
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"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
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"Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
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3. NO PATENT LICENSE
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NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
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ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
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respect to this software.
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You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
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by appropriate patent licenses.
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4. DISCLAIMER
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This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
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"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
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of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
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including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
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or business interruption, however caused and on any theory of liability, whether in contract, strict
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liability, or tort (including negligence), arising in any way out of the use of this software, even if
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advised of the possibility of such damage.
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5. CONTACT INFORMATION
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Fraunhofer Institute for Integrated Circuits IIS
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Attention: Audio and Multimedia Departments - FDK AAC LL
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Am Wolfsmantel 33
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91058 Erlangen, Germany
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www.iis.fraunhofer.de/amm
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amm-info@iis.fraunhofer.de
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----------------------------------------------------------------------------------------------------------- */
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/*!
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\file
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\brief FDK Fixed Point Arithmetic Library Interface
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*/
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#ifndef __TRANSCENDENT_H
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#define __TRANSCENDENT_H
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#include "sbrdecoder.h"
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#include "sbr_rom.h"
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/************************************************************************/
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/*!
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\brief Get number of octaves between frequencies a and b
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The Result is scaled with 1/8.
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The valid range for a and b is 1 to LOG_DUALIS_TABLE_SIZE.
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\return ld(a/b) / 8
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*/
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/************************************************************************/
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static inline FIXP_SGL FDK_getNumOctavesDiv8(INT a, /*!< lower band */
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INT b) /*!< upper band */
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{
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return ( (SHORT)((LONG)(CalcLdInt(b) - CalcLdInt(a))>>(FRACT_BITS-3)) );
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}
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/************************************************************************/
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/*!
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\brief Add two values given by mantissa and exponent.
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Mantissas are in fract format with values between 0 and 1. <br>
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The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br>
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*/
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/************************************************************************/
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inline void FDK_add_MantExp(FIXP_SGL a_m, /*!< Mantissa of 1st operand a */
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SCHAR a_e, /*!< Exponent of 1st operand a */
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FIXP_SGL b_m, /*!< Mantissa of 2nd operand b */
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SCHAR b_e, /*!< Exponent of 2nd operand b */
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FIXP_SGL *ptrSum_m, /*!< Mantissa of result */
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SCHAR *ptrSum_e) /*!< Exponent of result */
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{
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FIXP_DBL accu;
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int shift;
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int shiftAbs;
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FIXP_DBL shiftedMantissa;
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FIXP_DBL otherMantissa;
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/* Equalize exponents of the summands.
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For the smaller summand, the exponent is adapted and
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for compensation, the mantissa is shifted right. */
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shift = (int)(a_e - b_e);
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shiftAbs = (shift>0)? shift : -shift;
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shiftAbs = (shiftAbs < DFRACT_BITS-1)? shiftAbs : DFRACT_BITS-1;
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shiftedMantissa = (shift>0)? (FX_SGL2FX_DBL(b_m) >> shiftAbs) : (FX_SGL2FX_DBL(a_m) >> shiftAbs);
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otherMantissa = (shift>0)? FX_SGL2FX_DBL(a_m) : FX_SGL2FX_DBL(b_m);
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*ptrSum_e = (shift>0)? a_e : b_e;
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accu = (shiftedMantissa >> 1) + (otherMantissa >> 1);
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/* shift by 1 bit to avoid overflow */
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if ( (accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || (accu <= FL2FXCONST_DBL(-0.5f)) )
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*ptrSum_e += 1;
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else
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accu = (shiftedMantissa + otherMantissa);
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*ptrSum_m = FX_DBL2FX_SGL(accu);
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}
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inline void FDK_add_MantExp(FIXP_DBL a, /*!< Mantissa of 1st operand a */
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SCHAR a_e, /*!< Exponent of 1st operand a */
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FIXP_DBL b, /*!< Mantissa of 2nd operand b */
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SCHAR b_e, /*!< Exponent of 2nd operand b */
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FIXP_DBL *ptrSum, /*!< Mantissa of result */
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SCHAR *ptrSum_e) /*!< Exponent of result */
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{
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FIXP_DBL accu;
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int shift;
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int shiftAbs;
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FIXP_DBL shiftedMantissa;
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FIXP_DBL otherMantissa;
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/* Equalize exponents of the summands.
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For the smaller summand, the exponent is adapted and
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for compensation, the mantissa is shifted right. */
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shift = (int)(a_e - b_e);
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shiftAbs = (shift>0)? shift : -shift;
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shiftAbs = (shiftAbs < DFRACT_BITS-1)? shiftAbs : DFRACT_BITS-1;
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shiftedMantissa = (shift>0)? (b >> shiftAbs) : (a >> shiftAbs);
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otherMantissa = (shift>0)? a : b;
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*ptrSum_e = (shift>0)? a_e : b_e;
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accu = (shiftedMantissa >> 1) + (otherMantissa >> 1);
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/* shift by 1 bit to avoid overflow */
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if ( (accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || (accu <= FL2FXCONST_DBL(-0.5f)) )
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*ptrSum_e += 1;
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else
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accu = (shiftedMantissa + otherMantissa);
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*ptrSum = accu;
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}
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/************************************************************************/
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/*!
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\brief Divide two values given by mantissa and exponent.
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Mantissas are in fract format with values between 0 and 1. <br>
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The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br>
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For performance reasons, the division is based on a table lookup
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which limits accuracy.
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*/
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/************************************************************************/
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static inline void FDK_divide_MantExp(FIXP_SGL a_m, /*!< Mantissa of dividend a */
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SCHAR a_e, /*!< Exponent of dividend a */
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FIXP_SGL b_m, /*!< Mantissa of divisor b */
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SCHAR b_e, /*!< Exponent of divisor b */
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FIXP_SGL *ptrResult_m, /*!< Mantissa of quotient a/b */
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SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */
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{
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int preShift, postShift, index, shift;
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FIXP_DBL ratio_m;
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FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f);
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preShift = CntLeadingZeros(FX_SGL2FX_DBL(b_m));
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/*
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Shift b into the range from 0..INV_TABLE_SIZE-1,
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E.g. 10 bits must be skipped for INV_TABLE_BITS 8:
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- leave 8 bits as index for table
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- skip sign bit,
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- skip first bit of mantissa, because this is always the same (>0.5)
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We are dealing with energies, so we need not care
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about negative numbers
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*/
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/*
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The first interval has half width so the lowest bit of the index is
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needed for a doubled resolution.
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*/
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shift = (FRACT_BITS - 2 - INV_TABLE_BITS - preShift);
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index = (shift<0)? (LONG)b_m << (-shift) : (LONG)b_m >> shift;
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/* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */
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index &= (1 << (INV_TABLE_BITS+1)) - 1;
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/* Remove offset of half an interval */
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index--;
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/* Now the lowest bit is shifted out */
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index = index >> 1;
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/* Fetch inversed mantissa from table: */
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bInv_m = (index<0)? bInv_m : FDK_sbrDecoder_invTable[index];
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/* Multiply a with the inverse of b: */
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ratio_m = (index<0)? FX_SGL2FX_DBL(a_m >> 1) : fMultDiv2(bInv_m,a_m);
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postShift = CntLeadingZeros(ratio_m)-1;
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*ptrResult_m = FX_DBL2FX_SGL(ratio_m << postShift);
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*ptrResult_e = a_e - b_e + 1 + preShift - postShift;
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}
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static inline void FDK_divide_MantExp(FIXP_DBL a_m, /*!< Mantissa of dividend a */
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SCHAR a_e, /*!< Exponent of dividend a */
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FIXP_DBL b_m, /*!< Mantissa of divisor b */
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SCHAR b_e, /*!< Exponent of divisor b */
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FIXP_DBL *ptrResult_m, /*!< Mantissa of quotient a/b */
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SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */
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{
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int preShift, postShift, index, shift;
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FIXP_DBL ratio_m;
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FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f);
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preShift = CntLeadingZeros(b_m);
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/*
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Shift b into the range from 0..INV_TABLE_SIZE-1,
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E.g. 10 bits must be skipped for INV_TABLE_BITS 8:
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- leave 8 bits as index for table
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- skip sign bit,
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- skip first bit of mantissa, because this is always the same (>0.5)
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We are dealing with energies, so we need not care
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about negative numbers
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*/
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/*
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The first interval has half width so the lowest bit of the index is
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needed for a doubled resolution.
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*/
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shift = (DFRACT_BITS - 2 - INV_TABLE_BITS - preShift);
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index = (shift<0)? (LONG)b_m << (-shift) : (LONG)b_m >> shift;
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/* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */
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index &= (1 << (INV_TABLE_BITS+1)) - 1;
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/* Remove offset of half an interval */
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index--;
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/* Now the lowest bit is shifted out */
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index = index >> 1;
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/* Fetch inversed mantissa from table: */
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bInv_m = (index<0)? bInv_m : FDK_sbrDecoder_invTable[index];
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/* Multiply a with the inverse of b: */
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ratio_m = (index<0)? (a_m >> 1) : fMultDiv2(bInv_m,a_m);
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postShift = CntLeadingZeros(ratio_m)-1;
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*ptrResult_m = ratio_m << postShift;
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*ptrResult_e = a_e - b_e + 1 + preShift - postShift;
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}
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/*!
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\brief Calculate the squareroot of a number given by mantissa and exponent
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Mantissa is in fract format with values between 0 and 1. <br>
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The base for the exponent is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br>
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The operand is addressed via pointers and will be overwritten with the result.
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For performance reasons, the square root is based on a table lookup
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which limits accuracy.
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*/
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static inline void FDK_sqrt_MantExp(FIXP_DBL *mantissa, /*!< Pointer to mantissa */
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SCHAR *exponent,
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const SCHAR *destScale)
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{
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FIXP_DBL input_m = *mantissa;
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int input_e = (int) *exponent;
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FIXP_DBL result = FL2FXCONST_DBL(0.0f);
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int result_e = -FRACT_BITS;
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/* Call lookup square root, which does internally normalization. */
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result = sqrtFixp_lookup(input_m, &input_e);
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result_e = input_e;
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/* Write result */
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if (exponent==destScale) {
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*mantissa = result;
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*exponent = result_e;
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} else {
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int shift = result_e - *destScale;
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*mantissa = (shift>=0) ? result << (INT)fixMin(DFRACT_BITS-1,shift)
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: result >> (INT)fixMin(DFRACT_BITS-1,-shift);
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*exponent = *destScale;
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}
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}
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#endif
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