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      1 /* -----------------------------------------------------------------------------
      2 Software License for The Fraunhofer FDK AAC Codec Library for Android
      3 
      4  Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Frderung der angewandten
      5 Forschung e.V. All rights reserved.
      6 
      7  1.    INTRODUCTION
      8 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
      9 that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
     10 scheme for digital audio. This FDK AAC Codec software is intended to be used on
     11 a wide variety of Android devices.
     12 
     13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
     14 general perceptual audio codecs. AAC-ELD is considered the best-performing
     15 full-bandwidth communications codec by independent studies and is widely
     16 deployed. AAC has been standardized by ISO and IEC as part of the MPEG
     17 specifications.
     18 
     19 Patent licenses for necessary patent claims for the FDK AAC Codec (including
     20 those of Fraunhofer) may be obtained through Via Licensing
     21 (www.vialicensing.com) or through the respective patent owners individually for
     22 the purpose of encoding or decoding bit streams in products that are compliant
     23 with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
     24 Android devices already license these patent claims through Via Licensing or
     25 directly from the patent owners, and therefore FDK AAC Codec software may
     26 already be covered under those patent licenses when it is used for those
     27 licensed purposes only.
     28 
     29 Commercially-licensed AAC software libraries, including floating-point versions
     30 with enhanced sound quality, are also available from Fraunhofer. Users are
     31 encouraged to check the Fraunhofer website for additional applications
     32 information and documentation.
     33 
     34 2.    COPYRIGHT LICENSE
     35 
     36 Redistribution and use in source and binary forms, with or without modification,
     37 are permitted without payment of copyright license fees provided that you
     38 satisfy the following conditions:
     39 
     40 You must retain the complete text of this software license in redistributions of
     41 the FDK AAC Codec or your modifications thereto in source code form.
     42 
     43 You must retain the complete text of this software license in the documentation
     44 and/or other materials provided with redistributions of the FDK AAC Codec or
     45 your modifications thereto in binary form. You must make available free of
     46 charge copies of the complete source code of the FDK AAC Codec and your
     47 modifications thereto to recipients of copies in binary form.
     48 
     49 The name of Fraunhofer may not be used to endorse or promote products derived
     50 from this library without prior written permission.
     51 
     52 You may not charge copyright license fees for anyone to use, copy or distribute
     53 the FDK AAC Codec software or your modifications thereto.
     54 
     55 Your modified versions of the FDK AAC Codec must carry prominent notices stating
     56 that you changed the software and the date of any change. For modified versions
     57 of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
     58 must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
     59 AAC Codec Library for Android."
     60 
     61 3.    NO PATENT LICENSE
     62 
     63 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
     64 limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
     65 Fraunhofer provides no warranty of patent non-infringement with respect to this
     66 software.
     67 
     68 You may use this FDK AAC Codec software or modifications thereto only for
     69 purposes that are authorized by appropriate patent licenses.
     70 
     71 4.    DISCLAIMER
     72 
     73 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
     74 holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
     75 including but not limited to the implied warranties of merchantability and
     76 fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
     77 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
     78 or consequential damages, including but not limited to procurement of substitute
     79 goods or services; loss of use, data, or profits, or business interruption,
     80 however caused and on any theory of liability, whether in contract, strict
     81 liability, or tort (including negligence), arising in any way out of the use of
     82 this software, even if advised of the possibility of such damage.
     83 
     84 5.    CONTACT INFORMATION
     85 
     86 Fraunhofer Institute for Integrated Circuits IIS
     87 Attention: Audio and Multimedia Departments - FDK AAC LL
     88 Am Wolfsmantel 33
     89 91058 Erlangen, Germany
     90 
     91 www.iis.fraunhofer.de/amm
     92 amm-info (at) iis.fraunhofer.de
     93 ----------------------------------------------------------------------------- */
     94 
     95 /**************************** AAC decoder library ******************************
     96 
     97    Author(s):   Josef Hoepfl
     98 
     99    Description: joint stereo processing
    100 
    101 *******************************************************************************/
    102 
    103 #ifndef STEREO_H
    104 #define STEREO_H
    105 
    106 #include "machine_type.h"
    107 #include "FDK_bitstream.h"
    108 #include "common_fix.h"
    109 
    110 #define SFB_PER_PRED_BAND 2
    111 
    112 #define SR_FNA_OUT                                                           \
    113   0 /* Additional scaling of the CJointStereo_filterAndAdd()-output to avoid \
    114        overflows.    */
    115     /* The scaling factor can be set to 0 if the coefficients are prescaled
    116      * appropriately. */
    117 /* Prescaling via factor SF_FNA_COEFFS is done at compile-time but should only
    118  * be      */
    119 /* utilized if the coefficients are stored as FIXP_DBL. (cp. aac_rom.cpp/.h) */
    120 
    121 /* The NO_CPLX_PRED_BUGFIX-switch was introduced to enable decoding of
    122    conformance-streams in way that they are comparable to buggy
    123    reference-streams. This is established by storing the prediction direction
    124    for computation of the "downmix MDCT of previous frame". This is not standard
    125    compliant. Once correct reference-streams for complex-stereo-prediction are
    126    available this switch becomes obsolete.
    127 */
    128 /*#define NO_CPLX_PRED_BUGFIX*/
    129 
    130 enum { JointStereoMaximumGroups = 8, JointStereoMaximumBands = 64 };
    131 
    132 typedef struct {
    133   UCHAR pred_dir;  // 0 = prediction from mid to side channel, 1 = vice versa
    134   UCHAR
    135   igf_pred_dir;  // 0 = prediction from mid to side channel, 1 = vice versa
    136   UCHAR complex_coef;    // 0 = alpha_q_im[x] is 0 for all prediction bands, 1 =
    137                          // alpha_q_im[x] is transmitted via bitstream
    138   UCHAR use_prev_frame;  // 0 = use current frame for MDST estimation, 1 = use
    139                          // current and previous frame
    140 
    141   SHORT alpha_q_re[JointStereoMaximumGroups][JointStereoMaximumBands];
    142   SHORT alpha_q_im[JointStereoMaximumGroups][JointStereoMaximumBands];
    143 } CCplxPredictionData;
    144 
    145 /* joint stereo scratch memory (valid for this frame) */
    146 typedef struct {
    147   UCHAR MsMaskPresent;
    148   UCHAR MsUsed[JointStereoMaximumBands]; /*!< every arry element contains flags
    149                                             for up to 8 groups. this array is
    150                                             also utilized for complex stereo
    151                                             prediction. */
    152   UCHAR IGF_MsMaskPresent;
    153 
    154   UCHAR cplx_pred_flag; /* stereo complex prediction was signalled for this
    155                            frame */
    156   UCHAR igf_cplx_pred_flag;
    157 
    158   /* The following array and variable are needed for the case  when INF is
    159    * active */
    160   FIXP_DBL store_dmx_re_prev[1024];
    161   SHORT store_dmx_re_prev_e;
    162 
    163 } CJointStereoData;
    164 
    165 /* joint stereo persistent memory */
    166 typedef struct {
    167   UCHAR clearSpectralCoeffs; /* indicates that the spectral coeffs must be
    168                                 cleared because the transform splitting active
    169                                 flag of the left and right channel was different
    170                               */
    171 
    172   FIXP_DBL *scratchBuffer; /* pointer to scratch buffer */
    173 
    174   FIXP_DBL
    175   *spectralCoeffs[2]; /* spectral coefficients of this channel utilized by
    176                          complex stereo prediction */
    177   SHORT *specScale[2];
    178 
    179   SHORT alpha_q_re_prev[JointStereoMaximumGroups][JointStereoMaximumBands];
    180   SHORT alpha_q_im_prev[JointStereoMaximumGroups][JointStereoMaximumBands];
    181 
    182   UCHAR winSeqPrev;
    183   UCHAR winShapePrev;
    184   UCHAR winGroupsPrev;
    185 
    186 } CJointStereoPersistentData;
    187 
    188 /*!
    189   \brief Read joint stereo data from bitstream
    190 
    191   The function reads joint stereo data from bitstream.
    192 
    193   \param bs bit stream handle data source.
    194   \param pJointStereoData pointer to stereo data structure to receive decoded
    195   data. \param windowGroups number of window groups. \param
    196   scaleFactorBandsTransmitted number of transmitted scalefactor bands. \param
    197   flags decoder flags
    198 
    199   \return  0 on success, -1 on error.
    200 */
    201 int CJointStereo_Read(HANDLE_FDK_BITSTREAM bs,
    202                       CJointStereoData *pJointStereoData,
    203                       const int windowGroups,
    204                       const int scaleFactorBandsTransmitted,
    205                       const int max_sfb_ste_clear,
    206                       CJointStereoPersistentData *pJointStereoPersistentData,
    207                       CCplxPredictionData *cplxPredictionData,
    208                       int cplxPredictionActiv, int scaleFactorBandsTotal,
    209                       int windowSequence, const UINT flags);
    210 
    211 #endif /* #ifndef STEREO_H */
    212