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authorThe Android Open Source Project <initial-contribution@android.com>2012-07-11 10:15:24 -0700
committerThe Android Open Source Project <initial-contribution@android.com>2012-07-11 10:15:24 -0700
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tree57f3d390ebb0782cc0de0fb984c8ea7e45b4f386 /libSBRdec/src/transcendent.h
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+
+/* -----------------------------------------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright 1995 - 2012 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 and/or other materials
+provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
+You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
+modifications thereto to recipients of copies in binary form.
+
+The name of Fraunhofer may not be used to endorse or promote products derived from this library without
+prior written permission.
+
+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 that you changed the software
+and the date of any change. For modified versions 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 fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
+including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
+or business interruption, however caused and on any theory of liability, whether in contract, strict
+liability, or tort (including negligence), arising in any way out of the use of this software, even if
+advised of the possibility of such damage.
+
+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
+----------------------------------------------------------------------------------------------------------- */
+
+/*!
+ \file
+ \brief FDK Fixed Point Arithmetic Library Interface
+*/
+
+#ifndef __TRANSCENDENT_H
+#define __TRANSCENDENT_H
+
+#include "sbrdecoder.h"
+#include "sbr_rom.h"
+
+/************************************************************************/
+/*!
+ \brief Get number of octaves between frequencies a and b
+
+ The Result is scaled with 1/8.
+ The valid range for a and b is 1 to LOG_DUALIS_TABLE_SIZE.
+
+ \return ld(a/b) / 8
+*/
+/************************************************************************/
+static inline FIXP_SGL FDK_getNumOctavesDiv8(INT a, /*!< lower band */
+ INT b) /*!< upper band */
+{
+ return ( (SHORT)((LONG)(CalcLdInt(b) - CalcLdInt(a))>>(FRACT_BITS-3)) );
+}
+
+
+/************************************************************************/
+/*!
+ \brief Add two values given by mantissa and exponent.
+
+ Mantissas are in fract format with values between 0 and 1. <br>
+ The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br>
+*/
+/************************************************************************/
+inline void FDK_add_MantExp(FIXP_SGL a_m, /*!< Mantissa of 1st operand a */
+ SCHAR a_e, /*!< Exponent of 1st operand a */
+ FIXP_SGL b_m, /*!< Mantissa of 2nd operand b */
+ SCHAR b_e, /*!< Exponent of 2nd operand b */
+ FIXP_SGL *ptrSum_m, /*!< Mantissa of result */
+ SCHAR *ptrSum_e) /*!< Exponent of result */
+{
+ FIXP_DBL accu;
+ int shift;
+ int shiftAbs;
+
+ FIXP_DBL shiftedMantissa;
+ FIXP_DBL otherMantissa;
+
+ /* Equalize exponents of the summands.
+ For the smaller summand, the exponent is adapted and
+ for compensation, the mantissa is shifted right. */
+
+ shift = (int)(a_e - b_e);
+
+ shiftAbs = (shift>0)? shift : -shift;
+ shiftAbs = (shiftAbs < DFRACT_BITS-1)? shiftAbs : DFRACT_BITS-1;
+ shiftedMantissa = (shift>0)? (FX_SGL2FX_DBL(b_m) >> shiftAbs) : (FX_SGL2FX_DBL(a_m) >> shiftAbs);
+ otherMantissa = (shift>0)? FX_SGL2FX_DBL(a_m) : FX_SGL2FX_DBL(b_m);
+ *ptrSum_e = (shift>0)? a_e : b_e;
+
+ accu = (shiftedMantissa >> 1) + (otherMantissa >> 1);
+ /* shift by 1 bit to avoid overflow */
+
+ if ( (accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || (accu <= FL2FXCONST_DBL(-0.5f)) )
+ *ptrSum_e += 1;
+ else
+ accu = (shiftedMantissa + otherMantissa);
+
+ *ptrSum_m = FX_DBL2FX_SGL(accu);
+
+}
+
+inline void FDK_add_MantExp(FIXP_DBL a, /*!< Mantissa of 1st operand a */
+ SCHAR a_e, /*!< Exponent of 1st operand a */
+ FIXP_DBL b, /*!< Mantissa of 2nd operand b */
+ SCHAR b_e, /*!< Exponent of 2nd operand b */
+ FIXP_DBL *ptrSum, /*!< Mantissa of result */
+ SCHAR *ptrSum_e) /*!< Exponent of result */
+{
+ FIXP_DBL accu;
+ int shift;
+ int shiftAbs;
+
+ FIXP_DBL shiftedMantissa;
+ FIXP_DBL otherMantissa;
+
+ /* Equalize exponents of the summands.
+ For the smaller summand, the exponent is adapted and
+ for compensation, the mantissa is shifted right. */
+
+ shift = (int)(a_e - b_e);
+
+ shiftAbs = (shift>0)? shift : -shift;
+ shiftAbs = (shiftAbs < DFRACT_BITS-1)? shiftAbs : DFRACT_BITS-1;
+ shiftedMantissa = (shift>0)? (b >> shiftAbs) : (a >> shiftAbs);
+ otherMantissa = (shift>0)? a : b;
+ *ptrSum_e = (shift>0)? a_e : b_e;
+
+ accu = (shiftedMantissa >> 1) + (otherMantissa >> 1);
+ /* shift by 1 bit to avoid overflow */
+
+ if ( (accu >= (FL2FXCONST_DBL(0.5f) - (FIXP_DBL)1)) || (accu <= FL2FXCONST_DBL(-0.5f)) )
+ *ptrSum_e += 1;
+ else
+ accu = (shiftedMantissa + otherMantissa);
+
+ *ptrSum = accu;
+
+}
+
+/************************************************************************/
+/*!
+ \brief Divide two values given by mantissa and exponent.
+
+ Mantissas are in fract format with values between 0 and 1. <br>
+ The base for exponents is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br>
+
+ For performance reasons, the division is based on a table lookup
+ which limits accuracy.
+*/
+/************************************************************************/
+static inline void FDK_divide_MantExp(FIXP_SGL a_m, /*!< Mantissa of dividend a */
+ SCHAR a_e, /*!< Exponent of dividend a */
+ FIXP_SGL b_m, /*!< Mantissa of divisor b */
+ SCHAR b_e, /*!< Exponent of divisor b */
+ FIXP_SGL *ptrResult_m, /*!< Mantissa of quotient a/b */
+ SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */
+
+{
+ int preShift, postShift, index, shift;
+ FIXP_DBL ratio_m;
+ FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f);
+
+ preShift = CntLeadingZeros(FX_SGL2FX_DBL(b_m));
+
+ /*
+ Shift b into the range from 0..INV_TABLE_SIZE-1,
+
+ E.g. 10 bits must be skipped for INV_TABLE_BITS 8:
+ - leave 8 bits as index for table
+ - skip sign bit,
+ - skip first bit of mantissa, because this is always the same (>0.5)
+
+ We are dealing with energies, so we need not care
+ about negative numbers
+ */
+
+ /*
+ The first interval has half width so the lowest bit of the index is
+ needed for a doubled resolution.
+ */
+ shift = (FRACT_BITS - 2 - INV_TABLE_BITS - preShift);
+
+ index = (shift<0)? (LONG)b_m << (-shift) : (LONG)b_m >> shift;
+
+
+ /* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */
+ index &= (1 << (INV_TABLE_BITS+1)) - 1;
+
+ /* Remove offset of half an interval */
+ index--;
+
+ /* Now the lowest bit is shifted out */
+ index = index >> 1;
+
+ /* Fetch inversed mantissa from table: */
+ bInv_m = (index<0)? bInv_m : FDK_sbrDecoder_invTable[index];
+
+ /* Multiply a with the inverse of b: */
+ ratio_m = (index<0)? FX_SGL2FX_DBL(a_m >> 1) : fMultDiv2(bInv_m,a_m);
+
+ postShift = CntLeadingZeros(ratio_m)-1;
+
+ *ptrResult_m = FX_DBL2FX_SGL(ratio_m << postShift);
+ *ptrResult_e = a_e - b_e + 1 + preShift - postShift;
+}
+
+static inline void FDK_divide_MantExp(FIXP_DBL a_m, /*!< Mantissa of dividend a */
+ SCHAR a_e, /*!< Exponent of dividend a */
+ FIXP_DBL b_m, /*!< Mantissa of divisor b */
+ SCHAR b_e, /*!< Exponent of divisor b */
+ FIXP_DBL *ptrResult_m, /*!< Mantissa of quotient a/b */
+ SCHAR *ptrResult_e) /*!< Exponent of quotient a/b */
+
+{
+ int preShift, postShift, index, shift;
+ FIXP_DBL ratio_m;
+ FIXP_SGL bInv_m = FL2FXCONST_SGL(0.0f);
+
+ preShift = CntLeadingZeros(b_m);
+
+ /*
+ Shift b into the range from 0..INV_TABLE_SIZE-1,
+
+ E.g. 10 bits must be skipped for INV_TABLE_BITS 8:
+ - leave 8 bits as index for table
+ - skip sign bit,
+ - skip first bit of mantissa, because this is always the same (>0.5)
+
+ We are dealing with energies, so we need not care
+ about negative numbers
+ */
+
+ /*
+ The first interval has half width so the lowest bit of the index is
+ needed for a doubled resolution.
+ */
+ shift = (DFRACT_BITS - 2 - INV_TABLE_BITS - preShift);
+
+ index = (shift<0)? (LONG)b_m << (-shift) : (LONG)b_m >> shift;
+
+
+ /* The index has INV_TABLE_BITS +1 valid bits here. Clear the other bits. */
+ index &= (1 << (INV_TABLE_BITS+1)) - 1;
+
+ /* Remove offset of half an interval */
+ index--;
+
+ /* Now the lowest bit is shifted out */
+ index = index >> 1;
+
+ /* Fetch inversed mantissa from table: */
+ bInv_m = (index<0)? bInv_m : FDK_sbrDecoder_invTable[index];
+
+ /* Multiply a with the inverse of b: */
+ ratio_m = (index<0)? (a_m >> 1) : fMultDiv2(bInv_m,a_m);
+
+ postShift = CntLeadingZeros(ratio_m)-1;
+
+ *ptrResult_m = ratio_m << postShift;
+ *ptrResult_e = a_e - b_e + 1 + preShift - postShift;
+}
+
+/*!
+ \brief Calculate the squareroot of a number given by mantissa and exponent
+
+ Mantissa is in fract format with values between 0 and 1. <br>
+ The base for the exponent is 2. Example: \f$ a = a\_m * 2^{a\_e} \f$<br>
+ The operand is addressed via pointers and will be overwritten with the result.
+
+ For performance reasons, the square root is based on a table lookup
+ which limits accuracy.
+*/
+static inline void FDK_sqrt_MantExp(FIXP_DBL *mantissa, /*!< Pointer to mantissa */
+ SCHAR *exponent,
+ const SCHAR *destScale)
+{
+ FIXP_DBL input_m = *mantissa;
+ int input_e = (int) *exponent;
+ FIXP_DBL result = FL2FXCONST_DBL(0.0f);
+ int result_e = -FRACT_BITS;
+
+ /* Call lookup square root, which does internally normalization. */
+ result = sqrtFixp_lookup(input_m, &input_e);
+ result_e = input_e;
+
+ /* Write result */
+ if (exponent==destScale) {
+ *mantissa = result;
+ *exponent = result_e;
+ } else {
+ int shift = result_e - *destScale;
+ *mantissa = (shift>=0) ? result << (INT)fixMin(DFRACT_BITS-1,shift)
+ : result >> (INT)fixMin(DFRACT_BITS-1,-shift);
+ *exponent = *destScale;
+ }
+}
+
+
+#endif