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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 /***************************************************************************\
     85 *
     86  *   filename: ldfiltbank.c
     87  *   project : MPEG-4 Audio Decoder
     88  *   contents/description: low delay filterbank
     89  *
     90 \***************************************************************************/
     91 
     92 #include "ldfiltbank.h"
     93 
     94 
     95 #include "aac_rom.h"
     96 #include "dct.h"
     97 #include "FDK_tools_rom.h"
     98 #include "mdct.h"
     99 
    100 #define LDFB_HEADROOM 2
    101 
    102 static void multE2_DinvF_fdk(INT_PCM *output, FIXP_DBL* x, const FIXP_WTB* fb, FIXP_DBL* z, const int N, const int  stride)
    103 {
    104   int i, scale;
    105 
    106   /*  scale for FIXP_DBL -> INT_PCM conversion. */
    107   scale = (DFRACT_BITS - SAMPLE_BITS) - LDFB_HEADROOM;
    108 
    109   for(i=0;i<N/4;i++)
    110   {
    111     FIXP_DBL z0, z2, tmp;
    112 
    113     z2 = x[N/2+i];
    114     z0 = z2 + ( fMultDiv2(z[N/2+i], fb[2*N + i]) >> (-WTS2-1) );
    115 
    116     z[N/2+i] = x[N/2-1-i] + ( fMultDiv2(z[N + i], fb[2*N + N/2 + i]) >> (-WTS2-1) );
    117 
    118     tmp = ( fMultDiv2(z[N/2+i], fb[N+N/2-1-i]) + fMultDiv2(z[i], fb[N+N/2+i]) ) ;
    119 
    120 #if (SAMPLE_BITS <= 16)
    121     FDK_ASSERT( (-WTS1-1 + scale) >= 0);
    122     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp, -WTS1-1 + scale, SAMPLE_BITS);
    123 #else
    124     FDK_ASSERT( (WTS1+1 - scale) >= 0);
    125     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp, WTS1+1 - scale, SAMPLE_BITS);
    126 #endif
    127 
    128     z[i] = z0;
    129     z[N + i] = z2;
    130   }
    131 
    132   for(i=N/4;i<N/2;i++)
    133   {
    134     FIXP_DBL z0, z2, tmp0, tmp1;
    135 
    136     z2 = x[N/2+i];
    137     z0 = z2 + ( fMultDiv2(z[N/2+i], fb[2*N + i]) >> (-WTS2-1) );
    138 
    139     z[N/2+i] = x[N/2-1-i] + ( fMultDiv2(z[N + i], fb[2*N + N/2 + i]) >> (-WTS2-1) );
    140 
    141     tmp0 = ( fMultDiv2(z[N/2+i], fb[N/2-1-i])   + fMultDiv2(z[i], fb[N/2+i])   ) ;
    142     tmp1 = ( fMultDiv2(z[N/2+i], fb[N+N/2-1-i]) + fMultDiv2(z[i], fb[N+N/2+i]) ) ;
    143 
    144 #if (SAMPLE_BITS <= 16)
    145     FDK_ASSERT( (-WTS0-1 + scale) >= 0);
    146     output[(i-N/4)*stride]     = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS);
    147     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp1, -WTS1-1 + scale, SAMPLE_BITS);
    148 #else
    149     FDK_ASSERT( (WTS0+1 - scale) >= 0);
    150     output[(i-N/4)*stride]     = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS);
    151     output[(N*3/4-1-i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp1, WTS1+1 - scale, SAMPLE_BITS);
    152 #endif
    153     z[i] = z0;
    154     z[N + i] = z2;
    155   }
    156 
    157   /* Exchange quarter parts of x to bring them in the "right" order */
    158   for(i=0;i<N/4;i++)
    159   {
    160     FIXP_DBL tmp0 = fMultDiv2(z[i], fb[N/2+i]);
    161 
    162 #if (SAMPLE_BITS <= 16)
    163     FDK_ASSERT( (-WTS0-1 + scale) >= 0);
    164     output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_RIGHT_SHIFT(tmp0, -WTS0-1 + scale, SAMPLE_BITS);
    165 #else
    166     FDK_ASSERT( (WTS0+1 - scale) >= 0);
    167     output[(N*3/4 + i)*stride] = (INT_PCM)SATURATE_LEFT_SHIFT(tmp0, WTS0+1 - scale, SAMPLE_BITS);
    168 #endif
    169   }
    170 }
    171 
    172 int InvMdctTransformLowDelay_fdk (FIXP_DBL *mdctData, const int mdctData_e, INT_PCM *output, FIXP_DBL *fs_buffer, const int stride, const int N) {
    173 
    174   const FIXP_WTB *coef;
    175   FIXP_DBL gain = (FIXP_DBL)0;
    176   int scale = mdctData_e + MDCT_OUT_HEADROOM - LDFB_HEADROOM; /* The LDFB_HEADROOM is compensated inside multE2_DinvF_fdk() below */
    177 
    178   /* Select LD window slope */
    179   if (N == 512)
    180     coef = (FIXP_WTB*)LowDelaySynthesis512;
    181   else
    182     coef = (FIXP_WTB*)LowDelaySynthesis480;
    183 
    184   /*
    185      Apply exponent and 1/N factor.
    186      Note: "scale" is off by one because for LD_MDCT the window length is twice
    187      the window length of a regular MDCT. This is corrected inside multE2_DinvF_fdk().
    188      Refer to ISO/IEC 14496-3:2009 page 277, chapter 4.6.20.2 "Low Delay Window".
    189    */
    190   imdct_gain(&gain, &scale, N);
    191 
    192   dct_IV(mdctData, N, &scale);
    193 
    194   if (gain != (FIXP_DBL)0) {
    195     scaleValuesWithFactor(mdctData, gain, N, scale);
    196   } else {
    197     scaleValues(mdctData, N, scale);
    198   }
    199 
    200   /* Since all exponent and factors have been applied, current exponent is zero. */
    201   multE2_DinvF_fdk(output, mdctData, coef, fs_buffer, N, stride);
    202 
    203   return (1);
    204 }
    205 
    206 
    207 
    208 
    209