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 /******************* Library for basic calculation routines ******************** 96 97 Author(s): Josef Hoepfl, DSP Solutions 98 99 Description: Fix point FFT 100 101 *******************************************************************************/ 102 103 #ifndef FFT_H 104 #define FFT_H 105 106 #include "common_fix.h" 107 108 /** 109 * \brief Perform an inplace complex valued FFT of length 2^n 110 * 111 * \param length Length of the FFT to be calculated. 112 * \param pInput Input/Output data buffer. The input data must have at least 1 113 * bit scale headroom. The values are interleaved, real/imag pairs. 114 * \param scalefactor Pointer to an INT, which contains the current scale of the 115 * input data, which is updated according to the FFT scale. 116 */ 117 void fft(int length, FIXP_DBL *pInput, INT *scalefactor); 118 119 /** 120 * \brief Perform an inplace complex valued IFFT of length 2^n 121 * 122 * \param length Length of the FFT to be calculated. 123 * \param pInput Input/Output data buffer. The input data must have at least 1 124 * bit scale headroom. The values are interleaved, real/imag pairs. 125 * \param scalefactor Pointer to an INT, which contains the current scale of the 126 * input data, which is updated according to the IFFT scale. 127 */ 128 void ifft(int length, FIXP_DBL *pInput, INT *scalefactor); 129 130 /* 131 * Frequently used and fixed short length FFTs. 132 */ 133 134 #ifndef FUNCTION_fft_4 135 /** 136 * \brief Perform an inplace complex valued FFT of length 4 137 * 138 * \param pInput Input/Output data buffer. The input data must have at least 1 139 * bit scale headroom. The values are interleaved, real/imag pairs. 140 */ 141 LNK_SECTION_CODE_L1 142 static void FDK_FORCEINLINE fft_4(FIXP_DBL *x) { 143 FIXP_DBL a00, a10, a20, a30, tmp0, tmp1; 144 145 a00 = (x[0] + x[4]) >> 1; /* Re A + Re B */ 146 a10 = (x[2] + x[6]) >> 1; /* Re C + Re D */ 147 a20 = (x[1] + x[5]) >> 1; /* Im A + Im B */ 148 a30 = (x[3] + x[7]) >> 1; /* Im C + Im D */ 149 150 x[0] = a00 + a10; /* Re A' = Re A + Re B + Re C + Re D */ 151 x[1] = a20 + a30; /* Im A' = Im A + Im B + Im C + Im D */ 152 153 tmp0 = a00 - x[4]; /* Re A - Re B */ 154 tmp1 = a20 - x[5]; /* Im A - Im B */ 155 156 x[4] = a00 - a10; /* Re C' = Re A + Re B - Re C - Re D */ 157 x[5] = a20 - a30; /* Im C' = Im A + Im B - Im C - Im D */ 158 159 a10 = a10 - x[6]; /* Re C - Re D */ 160 a30 = a30 - x[7]; /* Im C - Im D */ 161 162 x[2] = tmp0 + a30; /* Re B' = Re A - Re B + Im C - Im D */ 163 x[6] = tmp0 - a30; /* Re D' = Re A - Re B - Im C + Im D */ 164 x[3] = tmp1 - a10; /* Im B' = Im A - Im B - Re C + Re D */ 165 x[7] = tmp1 + a10; /* Im D' = Im A - Im B + Re C - Re D */ 166 } 167 #endif /* FUNCTION_fft_4 */ 168 169 #ifndef FUNCTION_fft_8 170 LNK_SECTION_CODE_L1 171 static void FDK_FORCEINLINE fft_8(FIXP_DBL *x) { 172 FIXP_SPK w_PiFOURTH = {{FIXP_SGL(0x5A82), FIXP_SGL(0x5A82)}}; 173 174 FIXP_DBL a00, a10, a20, a30; 175 FIXP_DBL y[16]; 176 177 a00 = (x[0] + x[8]) >> 1; 178 a10 = x[4] + x[12]; 179 a20 = (x[1] + x[9]) >> 1; 180 a30 = x[5] + x[13]; 181 182 y[0] = a00 + (a10 >> 1); 183 y[4] = a00 - (a10 >> 1); 184 y[1] = a20 + (a30 >> 1); 185 y[5] = a20 - (a30 >> 1); 186 187 a00 = a00 - x[8]; 188 a10 = (a10 >> 1) - x[12]; 189 a20 = a20 - x[9]; 190 a30 = (a30 >> 1) - x[13]; 191 192 y[2] = a00 + a30; 193 y[6] = a00 - a30; 194 y[3] = a20 - a10; 195 y[7] = a20 + a10; 196 197 a00 = (x[2] + x[10]) >> 1; 198 a10 = x[6] + x[14]; 199 a20 = (x[3] + x[11]) >> 1; 200 a30 = x[7] + x[15]; 201 202 y[8] = a00 + (a10 >> 1); 203 y[12] = a00 - (a10 >> 1); 204 y[9] = a20 + (a30 >> 1); 205 y[13] = a20 - (a30 >> 1); 206 207 a00 = a00 - x[10]; 208 a10 = (a10 >> 1) - x[14]; 209 a20 = a20 - x[11]; 210 a30 = (a30 >> 1) - x[15]; 211 212 y[10] = a00 + a30; 213 y[14] = a00 - a30; 214 y[11] = a20 - a10; 215 y[15] = a20 + a10; 216 217 FIXP_DBL vr, vi, ur, ui; 218 219 ur = y[0] >> 1; 220 ui = y[1] >> 1; 221 vr = y[8]; 222 vi = y[9]; 223 x[0] = ur + (vr >> 1); 224 x[1] = ui + (vi >> 1); 225 x[8] = ur - (vr >> 1); 226 x[9] = ui - (vi >> 1); 227 228 ur = y[4] >> 1; 229 ui = y[5] >> 1; 230 vi = y[12]; 231 vr = y[13]; 232 x[4] = ur + (vr >> 1); 233 x[5] = ui - (vi >> 1); 234 x[12] = ur - (vr >> 1); 235 x[13] = ui + (vi >> 1); 236 237 ur = y[10]; 238 ui = y[11]; 239 240 cplxMultDiv2(&vi, &vr, ui, ur, w_PiFOURTH); 241 242 ur = y[2]; 243 ui = y[3]; 244 x[2] = (ur >> 1) + vr; 245 x[3] = (ui >> 1) + vi; 246 x[10] = (ur >> 1) - vr; 247 x[11] = (ui >> 1) - vi; 248 249 ur = y[14]; 250 ui = y[15]; 251 252 cplxMultDiv2(&vr, &vi, ui, ur, w_PiFOURTH); 253 254 ur = y[6]; 255 ui = y[7]; 256 x[6] = (ur >> 1) + vr; 257 x[7] = (ui >> 1) - vi; 258 x[14] = (ur >> 1) - vr; 259 x[15] = (ui >> 1) + vi; 260 } 261 #endif /* FUNCTION_fft_8 */ 262 263 #endif 264
