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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 Decoder  **************************
     85 
     86    Author(s):   Josef Hoepfl
     87    Description: joint stereo processing
     88 
     89 ******************************************************************************/
     90 
     91 #include "stereo.h"
     92 
     93 
     94 #include "aac_rom.h"
     95 #include "FDK_bitstream.h"
     96 #include "channelinfo.h"
     97 
     98 enum
     99 {
    100   L = 0,
    101   R = 1
    102 };
    103 
    104 
    105 int CJointStereo_Read(
    106         HANDLE_FDK_BITSTREAM bs,
    107         CJointStereoData *pJointStereoData,
    108         const int windowGroups,
    109         const int scaleFactorBandsTransmitted,
    110         const UINT flags
    111         )
    112 {
    113   int group,band;
    114 
    115   pJointStereoData->MsMaskPresent = (UCHAR) FDKreadBits(bs,2);
    116 
    117   FDKmemclear(pJointStereoData->MsUsed, scaleFactorBandsTransmitted*sizeof(UCHAR));
    118 
    119   switch (pJointStereoData->MsMaskPresent)
    120   {
    121     case 0 : /* no M/S */
    122       /* all flags are already cleared */
    123       break ;
    124 
    125     case 1 : /* read ms_used */
    126 
    127       for (group=0; group<windowGroups; group++)
    128       {
    129         for (band=0; band<scaleFactorBandsTransmitted; band++)
    130         {
    131           pJointStereoData->MsUsed[band] |= (FDKreadBits(bs,1) << group);
    132         }
    133       }
    134       break ;
    135 
    136     case 2 : /* full spectrum M/S */
    137 
    138       for (band=0; band<scaleFactorBandsTransmitted; band++)
    139       {
    140         pJointStereoData->MsUsed[band] = 255 ;  /* set all flags to 1 */
    141       }
    142       break ;
    143   }
    144 
    145   return 0;
    146 }
    147 
    148 void CJointStereo_ApplyMS(
    149         CAacDecoderChannelInfo *pAacDecoderChannelInfo[2],
    150         const SHORT *pScaleFactorBandOffsets,
    151         const UCHAR *pWindowGroupLength,
    152         const int windowGroups,
    153         const int scaleFactorBandsTransmittedL,
    154         const int scaleFactorBandsTransmittedR
    155         )
    156 {
    157   CJointStereoData *pJointStereoData = &pAacDecoderChannelInfo[L]->pComData->jointStereoData;
    158   int window, group, scaleFactorBandsTransmitted;
    159 
    160   FDK_ASSERT(scaleFactorBandsTransmittedL == scaleFactorBandsTransmittedR);
    161   scaleFactorBandsTransmitted = scaleFactorBandsTransmittedL;
    162   for (window = 0, group = 0; group < windowGroups; group++)
    163   {
    164     UCHAR groupMask = 1 << group;
    165 
    166     for (int groupwin=0; groupwin<pWindowGroupLength[group]; groupwin++, window++)
    167     {
    168       int band;
    169       FIXP_DBL *leftSpectrum, *rightSpectrum;
    170       SHORT *leftScale = &pAacDecoderChannelInfo[L]->pDynData->aSfbScale[window*16];
    171       SHORT *rightScale = &pAacDecoderChannelInfo[R]->pDynData->aSfbScale[window*16];
    172 
    173       leftSpectrum = SPEC(pAacDecoderChannelInfo[L]->pSpectralCoefficient, window, pAacDecoderChannelInfo[L]->granuleLength);
    174       rightSpectrum = SPEC(pAacDecoderChannelInfo[R]->pSpectralCoefficient, window, pAacDecoderChannelInfo[R]->granuleLength);
    175 
    176       for (band=0; band<scaleFactorBandsTransmitted; band++)
    177       {
    178         if (pJointStereoData->MsUsed[band] & groupMask)
    179         {
    180           int lScale=leftScale[band];
    181           int rScale=rightScale[band];
    182           int commonScale=lScale > rScale ? lScale:rScale;
    183 
    184           /* ISO/IEC 14496-3 Chapter 4.6.8.1.1 :
    185              M/S joint channel coding can only be used if common_window is 1. */
    186           FDK_ASSERT(GetWindowSequence(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowSequence(&pAacDecoderChannelInfo[R]->icsInfo));
    187           FDK_ASSERT(GetWindowShape(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowShape(&pAacDecoderChannelInfo[R]->icsInfo));
    188 
    189           commonScale++;
    190           leftScale[band]=commonScale;
    191           rightScale[band]=commonScale;
    192 
    193           lScale = fMin(DFRACT_BITS-1, commonScale - lScale);
    194           rScale = fMin(DFRACT_BITS-1, commonScale - rScale);
    195 
    196           FDK_ASSERT(lScale >= 0 && rScale >= 0);
    197 
    198           for (int index=pScaleFactorBandOffsets[band]; index<pScaleFactorBandOffsets[band+1]; index++)
    199           {
    200             FIXP_DBL leftCoefficient  = leftSpectrum [index] ;
    201             FIXP_DBL rightCoefficient = rightSpectrum [index] ;
    202 
    203             leftCoefficient >>= lScale ;
    204             rightCoefficient >>= rScale ;
    205 
    206             leftSpectrum [index] = leftCoefficient + rightCoefficient ;
    207             rightSpectrum [index] = leftCoefficient - rightCoefficient ;
    208           }
    209         }
    210       }
    211     }
    212   }
    213 
    214   /* Reset MsUsed flags if no explicit signalling was transmitted. Necessary for intensity coding.
    215      PNS correlation signalling was mapped before calling CJointStereo_ApplyMS(). */
    216   if (pJointStereoData->MsMaskPresent == 2) {
    217     FDKmemclear(pJointStereoData->MsUsed, JointStereoMaximumBands * sizeof(UCHAR));
    218   }
    219 }
    220 
    221 void CJointStereo_ApplyIS(
    222         CAacDecoderChannelInfo *pAacDecoderChannelInfo[2],
    223         const SHORT *pScaleFactorBandOffsets,
    224         const UCHAR *pWindowGroupLength,
    225         const int windowGroups,
    226         const int scaleFactorBandsTransmitted,
    227         const UINT CommonWindow
    228         )
    229 {
    230   CJointStereoData *pJointStereoData = &pAacDecoderChannelInfo[L]->pComData->jointStereoData;
    231 
    232   for (int window=0,group=0; group<windowGroups; group++)
    233   {
    234     UCHAR *CodeBook;
    235     SHORT *ScaleFactor;
    236     UCHAR groupMask = 1 << group;
    237 
    238     CodeBook = &pAacDecoderChannelInfo[R]->pDynData->aCodeBook[group*16];
    239     ScaleFactor = &pAacDecoderChannelInfo[R]->pDynData->aScaleFactor[group*16];
    240 
    241     for (int groupwin=0; groupwin<pWindowGroupLength[group]; groupwin++, window++)
    242     {
    243       FIXP_DBL *leftSpectrum, *rightSpectrum;
    244       SHORT *leftScale = &pAacDecoderChannelInfo[L]->pDynData->aSfbScale[window*16];
    245       SHORT *rightScale = &pAacDecoderChannelInfo[R]->pDynData->aSfbScale[window*16];
    246       int band;
    247 
    248       leftSpectrum = SPEC(pAacDecoderChannelInfo[L]->pSpectralCoefficient, window, pAacDecoderChannelInfo[L]->granuleLength);
    249       rightSpectrum = SPEC(pAacDecoderChannelInfo[R]->pSpectralCoefficient, window, pAacDecoderChannelInfo[R]->granuleLength);
    250 
    251       for (band=0; band<scaleFactorBandsTransmitted; band++)
    252       {
    253         if ((CodeBook [band] == INTENSITY_HCB) ||
    254             (CodeBook [band] == INTENSITY_HCB2))
    255         {
    256           int bandScale = -(ScaleFactor [band] + 100) ;
    257 
    258           int msb = bandScale >> 2 ;
    259           int lsb = bandScale & 0x03 ;
    260 
    261           /* exponent of MantissaTable[lsb][0] is 1, thus msb+1 below. */
    262           FIXP_DBL scale = MantissaTable[lsb][0];
    263 
    264           /* ISO/IEC 14496-3 Chapter 4.6.8.2.3 :
    265              The use of intensity stereo coding is signaled by the use of the pseudo codebooks
    266              INTENSITY_HCB and INTENSITY_HCB2 (15 and 14) only in the right channel of a
    267              channel_pair_element() having a common ics_info() (common_window == 1). */
    268           FDK_ASSERT(GetWindowSequence(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowSequence(&pAacDecoderChannelInfo[R]->icsInfo));
    269           FDK_ASSERT(GetWindowShape(&pAacDecoderChannelInfo[L]->icsInfo) == GetWindowShape(&pAacDecoderChannelInfo[R]->icsInfo));
    270 
    271           rightScale[band] = leftScale[band]+msb+1;
    272 
    273           if (CommonWindow && (pJointStereoData->MsUsed[band] & groupMask))
    274           {
    275 
    276             if (CodeBook[band] == INTENSITY_HCB) /* _NOT_ in-phase */
    277             {
    278               scale = -scale ;
    279             }
    280           }
    281           else
    282           {
    283             if (CodeBook[band] == INTENSITY_HCB2) /* out-of-phase */
    284             {
    285               scale = -scale ;
    286             }
    287           }
    288 
    289           for (int index=pScaleFactorBandOffsets[band]; index<pScaleFactorBandOffsets[band+1]; index++)
    290           {
    291             rightSpectrum[index] = fMult(leftSpectrum[index],scale);
    292           }
    293         }
    294       }
    295     }
    296   }
    297 }
    298