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
