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      1 
      2 /* -----------------------------------------------------------------------------------------------------------
      3 Software License for The Fraunhofer FDK AAC Codec Library for Android
      4 
      5  Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur Frderung der angewandten Forschung e.V.
      6   All rights reserved.
      7 
      8  1.    INTRODUCTION
      9 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
     10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
     11 This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
     12 
     13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
     14 audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
     15 independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
     16 of the MPEG specifications.
     17 
     18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
     19 may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
     20 individually for the purpose of encoding or decoding bit streams in products that are compliant with
     21 the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
     22 these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
     23 software may already be covered under those patent licenses when it is used for those licensed purposes only.
     24 
     25 Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
     26 are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
     27 applications information and documentation.
     28 
     29 2.    COPYRIGHT LICENSE
     30 
     31 Redistribution and use in source and binary forms, with or without modification, are permitted without
     32 payment of copyright license fees provided that you satisfy the following conditions:
     33 
     34 You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
     35 your modifications thereto in source code form.
     36 
     37 You must retain the complete text of this software license in the documentation and/or other materials
     38 provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
     39 You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
     40 modifications thereto to recipients of copies in binary form.
     41 
     42 The name of Fraunhofer may not be used to endorse or promote products derived from this library without
     43 prior written permission.
     44 
     45 You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
     46 software or your modifications thereto.
     47 
     48 Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
     49 and the date of any change. For modified versions of the FDK AAC Codec, the term
     50 "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
     51 "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
     52 
     53 3.    NO PATENT LICENSE
     54 
     55 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
     56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
     57 respect to this software.
     58 
     59 You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
     60 by appropriate patent licenses.
     61 
     62 4.    DISCLAIMER
     63 
     64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
     65 "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
     66 of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
     67 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
     68 including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
     69 or business interruption, however caused and on any theory of liability, whether in contract, strict
     70 liability, or tort (including negligence), arising in any way out of the use of this software, even if
     71 advised of the possibility of such damage.
     72 
     73 5.    CONTACT INFORMATION
     74 
     75 Fraunhofer Institute for Integrated Circuits IIS
     76 Attention: Audio and Multimedia Departments - FDK AAC LL
     77 Am Wolfsmantel 33
     78 91058 Erlangen, Germany
     79 
     80 www.iis.fraunhofer.de/amm
     81 amm-info (at) iis.fraunhofer.de
     82 ----------------------------------------------------------------------------------------------------------- */
     83 
     84 /*****************************  MPEG-4 AAC Encoder  **************************
     85 
     86    Initial author:       M. Werner
     87    contents/description: Band/Line energy calculations
     88 
     89 ******************************************************************************/
     90 
     91 #include "band_nrg.h"
     92 
     93 
     94 /*****************************************************************************
     95   functionname: FDKaacEnc_CalcSfbMaxScaleSpec
     96   description:
     97   input:
     98   output:
     99 *****************************************************************************/
    100 void
    101 FDKaacEnc_CalcSfbMaxScaleSpec(const FIXP_DBL *RESTRICT mdctSpectrum,
    102                               const INT      *RESTRICT bandOffset,
    103                               INT            *RESTRICT sfbMaxScaleSpec,
    104                               const INT       numBands)
    105 {
    106   INT i,j;
    107   FIXP_DBL maxSpc, tmp;
    108 
    109   for(i=0; i<numBands; i++) {
    110     maxSpc = (FIXP_DBL)0;
    111     for (j=bandOffset[i]; j<bandOffset[i+1]; j++) {
    112       tmp = fixp_abs(mdctSpectrum[j]);
    113       maxSpc = fixMax(maxSpc, tmp);
    114     }
    115     sfbMaxScaleSpec[i] = (maxSpc==(FIXP_DBL)0) ? (DFRACT_BITS-2) : CntLeadingZeros(maxSpc)-1;
    116     /* CountLeadingBits() is not necessary here since test value is always > 0 */
    117   }
    118 }
    119 
    120 /*****************************************************************************
    121   functionname: FDKaacEnc_CheckBandEnergyOptim
    122   description:
    123   input:
    124   output:
    125 *****************************************************************************/
    126 FIXP_DBL
    127 FDKaacEnc_CheckBandEnergyOptim(const FIXP_DBL *RESTRICT mdctSpectrum,
    128                                INT            *RESTRICT sfbMaxScaleSpec,
    129                                const INT      *RESTRICT bandOffset,
    130                                const INT       numBands,
    131                                FIXP_DBL       *RESTRICT bandEnergy,
    132                                FIXP_DBL       *RESTRICT bandEnergyLdData,
    133                                INT             minSpecShift)
    134 {
    135   INT i, j, scale, nr = 0;
    136   FIXP_DBL maxNrgLd = FL2FXCONST_DBL(-1.0f);
    137   FIXP_DBL maxNrg = 0;
    138   FIXP_DBL spec;
    139 
    140   for(i=0; i<numBands; i++) {
    141     scale = fixMax(0, sfbMaxScaleSpec[i]-4);
    142     FIXP_DBL tmp = 0;
    143     for (j=bandOffset[i]; j<bandOffset[i+1]; j++){
    144        spec = mdctSpectrum[j]<<scale;
    145        tmp = fPow2AddDiv2(tmp, spec);
    146     }
    147     bandEnergy[i] = tmp<<1;
    148 
    149     /* calculate ld of bandNrg, subtract scaling */
    150     bandEnergyLdData[i] = CalcLdData(bandEnergy[i]);
    151     if (bandEnergyLdData[i] != FL2FXCONST_DBL(-1.0f)) {
    152       bandEnergyLdData[i] -= scale*FL2FXCONST_DBL(2.0/64);
    153     }
    154     /* find index of maxNrg */
    155     if (bandEnergyLdData[i] > maxNrgLd) {
    156         maxNrgLd = bandEnergyLdData[i];
    157         nr = i;
    158     }
    159   }
    160 
    161   /* return unscaled maxNrg*/
    162   scale = fixMax(0,sfbMaxScaleSpec[nr]-4);
    163   scale = fixMax(2*(minSpecShift-scale),-(DFRACT_BITS-1));
    164 
    165   maxNrg = scaleValue(bandEnergy[nr], scale);
    166 
    167   return maxNrg;
    168 }
    169 
    170 /*****************************************************************************
    171   functionname: FDKaacEnc_CalcBandEnergyOptimLong
    172   description:
    173   input:
    174   output:
    175 *****************************************************************************/
    176 INT
    177 FDKaacEnc_CalcBandEnergyOptimLong(const FIXP_DBL *RESTRICT mdctSpectrum,
    178                                   INT            *RESTRICT sfbMaxScaleSpec,
    179                                   const INT      *RESTRICT bandOffset,
    180                                   const INT       numBands,
    181                                   FIXP_DBL       *RESTRICT bandEnergy,
    182                                   FIXP_DBL       *RESTRICT bandEnergyLdData)
    183 {
    184   INT i, j, shiftBits = 0;
    185   FIXP_DBL maxNrgLd = FL2FXCONST_DBL(0.0f);
    186 
    187   FIXP_DBL spec;
    188 
    189   for(i=0; i<numBands; i++) {
    190      INT leadingBits = sfbMaxScaleSpec[i]-4;            /* max sfbWidth = 96 ; 2^7=128 => 7/2 = 4 (spc*spc) */
    191      FIXP_DBL tmp = FL2FXCONST_DBL(0.0);
    192      /* don't use scaleValue() here, it increases workload quite sufficiently... */
    193      if (leadingBits>=0) {
    194         for (j=bandOffset[i];j<bandOffset[i+1];j++) {
    195            spec = mdctSpectrum[j]<<leadingBits;
    196            tmp = fPow2AddDiv2(tmp, spec);
    197         }
    198      } else {
    199         INT shift = -leadingBits;
    200         for (j=bandOffset[i];j<bandOffset[i+1];j++){
    201            spec = mdctSpectrum[j]>>shift;
    202            tmp = fPow2AddDiv2(tmp, spec);
    203         }
    204      }
    205      bandEnergy[i] = tmp<<1;
    206   }
    207 
    208   /* calculate ld of bandNrg, subtract scaling */
    209   LdDataVector(bandEnergy, bandEnergyLdData, numBands);
    210   for(i=numBands; i--!=0; ) {
    211       FIXP_DBL scaleDiff = (sfbMaxScaleSpec[i]-4)*FL2FXCONST_DBL(2.0/64);
    212 
    213       bandEnergyLdData[i] = (bandEnergyLdData[i] >= ((FL2FXCONST_DBL(-1.f)>>1) + (scaleDiff>>1)))
    214                           ? bandEnergyLdData[i]-scaleDiff : FL2FXCONST_DBL(-1.f);
    215       /* find maxNrgLd */
    216       maxNrgLd = fixMax(maxNrgLd, bandEnergyLdData[i]);
    217   }
    218 
    219   if (maxNrgLd<=(FIXP_DBL)0)
    220   {
    221      for(i=numBands; i--!=0; )
    222      {
    223          INT scale = fixMin((sfbMaxScaleSpec[i]-4)<<1,(DFRACT_BITS-1));
    224          bandEnergy[i] = scaleValue(bandEnergy[i], -scale);
    225      }
    226      return 0;
    227   }
    228   else
    229   {  /* scale down NRGs */
    230      while (maxNrgLd>FL2FXCONST_DBL(0.0f))
    231      {
    232         maxNrgLd -=  FL2FXCONST_DBL(2.0/64);
    233         shiftBits++;
    234      }
    235      for(i=numBands; i--!=0; )
    236      {
    237          INT scale = fixMin( ((sfbMaxScaleSpec[i]-4)+shiftBits)<<1, (DFRACT_BITS-1));
    238          bandEnergyLdData[i] -= shiftBits*FL2FXCONST_DBL(2.0/64);
    239          bandEnergy[i] = scaleValue(bandEnergy[i], -scale);
    240      }
    241      return shiftBits;
    242   }
    243 }
    244 
    245 
    246 /*****************************************************************************
    247   functionname: FDKaacEnc_CalcBandEnergyOptimShort
    248   description:
    249   input:
    250   output:
    251 *****************************************************************************/
    252 void
    253 FDKaacEnc_CalcBandEnergyOptimShort(const FIXP_DBL *RESTRICT mdctSpectrum,
    254                                    INT            *RESTRICT sfbMaxScaleSpec,
    255                                    const INT      *RESTRICT bandOffset,
    256                                    const INT       numBands,
    257                                    FIXP_DBL       *RESTRICT bandEnergy)
    258 {
    259   INT i, j;
    260 
    261   for(i=0; i<numBands; i++)
    262   {
    263     int leadingBits = sfbMaxScaleSpec[i]-3;            /* max sfbWidth = 36 ; 2^6=64 => 6/2 = 3 (spc*spc) */
    264     FIXP_DBL tmp = FL2FXCONST_DBL(0.0);
    265     for (j=bandOffset[i];j<bandOffset[i+1];j++)
    266     {
    267        FIXP_DBL spec = scaleValue(mdctSpectrum[j],leadingBits);
    268        tmp = fPow2AddDiv2(tmp, spec);
    269     }
    270     bandEnergy[i] = tmp;
    271   }
    272 
    273   for(i=0; i<numBands; i++)
    274   {
    275       INT scale = (2*(sfbMaxScaleSpec[i]-3))-1;         /* max sfbWidth = 36 ; 2^6=64 => 6/2 = 3 (spc*spc) */
    276       scale = fixMax(fixMin(scale,(DFRACT_BITS-1)),-(DFRACT_BITS-1));
    277       bandEnergy[i] = scaleValueSaturate(bandEnergy[i], -scale);
    278   }
    279 }
    280 
    281 
    282 /*****************************************************************************
    283   functionname: FDKaacEnc_CalcBandNrgMSOpt
    284   description:
    285   input:
    286   output:
    287 *****************************************************************************/
    288 void FDKaacEnc_CalcBandNrgMSOpt(const FIXP_DBL   *RESTRICT mdctSpectrumLeft,
    289                                 const FIXP_DBL   *RESTRICT mdctSpectrumRight,
    290                                 INT              *RESTRICT sfbMaxScaleSpecLeft,
    291                                 INT              *RESTRICT sfbMaxScaleSpecRight,
    292                                 const INT        *RESTRICT bandOffset,
    293                                 const INT         numBands,
    294                                 FIXP_DBL         *RESTRICT bandEnergyMid,
    295                                 FIXP_DBL         *RESTRICT bandEnergySide,
    296                                 INT               calcLdData,
    297                                 FIXP_DBL         *RESTRICT bandEnergyMidLdData,
    298                                 FIXP_DBL         *RESTRICT bandEnergySideLdData)
    299 {
    300   INT i, j, minScale;
    301   FIXP_DBL NrgMid, NrgSide, specm, specs;
    302 
    303   for (i=0; i<numBands; i++) {
    304 
    305     NrgMid = NrgSide = FL2FXCONST_DBL(0.0);
    306     minScale = fixMin(sfbMaxScaleSpecLeft[i], sfbMaxScaleSpecRight[i])-4;
    307     minScale = fixMax(0, minScale);
    308 
    309     if (minScale > 0) {
    310       for (j=bandOffset[i];j<bandOffset[i+1];j++) {
    311           FIXP_DBL specL = mdctSpectrumLeft[j]<<(minScale-1);
    312           FIXP_DBL specR = mdctSpectrumRight[j]<<(minScale-1);
    313           specm = specL + specR;
    314           specs = specL - specR;
    315           NrgMid = fPow2AddDiv2(NrgMid, specm);
    316           NrgSide = fPow2AddDiv2(NrgSide, specs);
    317       }
    318     } else {
    319       for (j=bandOffset[i];j<bandOffset[i+1];j++) {
    320           FIXP_DBL specL = mdctSpectrumLeft[j]>>1;
    321           FIXP_DBL specR = mdctSpectrumRight[j]>>1;
    322           specm = specL + specR;
    323           specs = specL - specR;
    324           NrgMid = fPow2AddDiv2(NrgMid, specm);
    325           NrgSide = fPow2AddDiv2(NrgSide, specs);
    326       }
    327     }
    328     bandEnergyMid[i] = NrgMid<<1;
    329     bandEnergySide[i] = NrgSide<<1;
    330   }
    331 
    332   if(calcLdData) {
    333     LdDataVector(bandEnergyMid, bandEnergyMidLdData, numBands);
    334     LdDataVector(bandEnergySide, bandEnergySideLdData, numBands);
    335   }
    336 
    337   for (i=0; i<numBands; i++)
    338   {
    339     INT minScale = fixMin(sfbMaxScaleSpecLeft[i], sfbMaxScaleSpecRight[i]);
    340     INT scale = fixMax(0, 2*(minScale-4));
    341 
    342     if (calcLdData)
    343     {
    344        /* using the minimal scaling of left and right channel can cause very small energies;
    345        check ldNrg before subtract scaling multiplication: fract*INT we don't need fMult */
    346 
    347        int minus = scale*FL2FXCONST_DBL(1.0/64);
    348 
    349        if (bandEnergyMidLdData[i] != FL2FXCONST_DBL(-1.0f))
    350          bandEnergyMidLdData[i] -= minus;
    351 
    352        if (bandEnergySideLdData[i] != FL2FXCONST_DBL(-1.0f))
    353          bandEnergySideLdData[i] -= minus;
    354     }
    355     scale = fixMin(scale, (DFRACT_BITS-1));
    356     bandEnergyMid[i]  >>= scale;
    357     bandEnergySide[i] >>= scale;
    358   }
    359 }
    360