1/* ----------------------------------------------------------------------------- 2Software License for The Fraunhofer FDK AAC Codec Library for Android 3 4© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten 5Forschung e.V. All rights reserved. 6 7 1. INTRODUCTION 8The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software 9that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding 10scheme for digital audio. This FDK AAC Codec software is intended to be used on 11a wide variety of Android devices. 12 13AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient 14general perceptual audio codecs. AAC-ELD is considered the best-performing 15full-bandwidth communications codec by independent studies and is widely 16deployed. AAC has been standardized by ISO and IEC as part of the MPEG 17specifications. 18 19Patent licenses for necessary patent claims for the FDK AAC Codec (including 20those of Fraunhofer) may be obtained through Via Licensing 21(www.vialicensing.com) or through the respective patent owners individually for 22the purpose of encoding or decoding bit streams in products that are compliant 23with the ISO/IEC MPEG audio standards. Please note that most manufacturers of 24Android devices already license these patent claims through Via Licensing or 25directly from the patent owners, and therefore FDK AAC Codec software may 26already be covered under those patent licenses when it is used for those 27licensed purposes only. 28 29Commercially-licensed AAC software libraries, including floating-point versions 30with enhanced sound quality, are also available from Fraunhofer. Users are 31encouraged to check the Fraunhofer website for additional applications 32information and documentation. 33 342. COPYRIGHT LICENSE 35 36Redistribution and use in source and binary forms, with or without modification, 37are permitted without payment of copyright license fees provided that you 38satisfy the following conditions: 39 40You must retain the complete text of this software license in redistributions of 41the FDK AAC Codec or your modifications thereto in source code form. 42 43You must retain the complete text of this software license in the documentation 44and/or other materials provided with redistributions of the FDK AAC Codec or 45your modifications thereto in binary form. You must make available free of 46charge copies of the complete source code of the FDK AAC Codec and your 47modifications thereto to recipients of copies in binary form. 48 49The name of Fraunhofer may not be used to endorse or promote products derived 50from this library without prior written permission. 51 52You may not charge copyright license fees for anyone to use, copy or distribute 53the FDK AAC Codec software or your modifications thereto. 54 55Your modified versions of the FDK AAC Codec must carry prominent notices stating 56that you changed the software and the date of any change. For modified versions 57of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android" 58must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK 59AAC Codec Library for Android." 60 613. NO PATENT LICENSE 62 63NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without 64limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE. 65Fraunhofer provides no warranty of patent non-infringement with respect to this 66software. 67 68You may use this FDK AAC Codec software or modifications thereto only for 69purposes that are authorized by appropriate patent licenses. 70 714. DISCLAIMER 72 73This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright 74holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, 75including but not limited to the implied warranties of merchantability and 76fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 77CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, 78or consequential damages, including but not limited to procurement of substitute 79goods or services; loss of use, data, or profits, or business interruption, 80however caused and on any theory of liability, whether in contract, strict 81liability, or tort (including negligence), arising in any way out of the use of 82this software, even if advised of the possibility of such damage. 83 845. CONTACT INFORMATION 85 86Fraunhofer Institute for Integrated Circuits IIS 87Attention: Audio and Multimedia Departments - FDK AAC LL 88Am Wolfsmantel 33 8991058 Erlangen, Germany 90 91www.iis.fraunhofer.de/amm 92amm-info@iis.fraunhofer.de 93----------------------------------------------------------------------------- */ 94 95/**************************** AAC decoder library ****************************** 96 97 Author(s): Josef Hoepfl 98 99 Description: perceptual noise substitution tool 100 101*******************************************************************************/ 102 103#include "aacdec_pns.h" 104 105#include "aac_ram.h" 106#include "aac_rom.h" 107#include "channelinfo.h" 108#include "block.h" 109#include "FDK_bitstream.h" 110 111#include "genericStds.h" 112 113#define NOISE_OFFSET 90 /* cf. ISO 14496-3 p. 175 */ 114 115/*! 116 \brief Reset InterChannel and PNS data 117 118 The function resets the InterChannel and PNS data 119*/ 120void CPns_ResetData(CPnsData *pPnsData, 121 CPnsInterChannelData *pPnsInterChannelData) { 122 FDK_ASSERT(pPnsData != NULL); 123 FDK_ASSERT(pPnsInterChannelData != NULL); 124 /* Assign pointer always, since pPnsData is not persistent data */ 125 pPnsData->pPnsInterChannelData = pPnsInterChannelData; 126 pPnsData->PnsActive = 0; 127 pPnsData->CurrentEnergy = 0; 128 129 FDKmemclear(pPnsData->pnsUsed, (8 * 16) * sizeof(UCHAR)); 130 FDKmemclear(pPnsInterChannelData->correlated, (8 * 16) * sizeof(UCHAR)); 131} 132 133/*! 134 \brief Update PNS noise generator state. 135 136 The function sets the seed for PNS noise generation. 137 It can be used to link two or more channels in terms of PNS. 138*/ 139void CPns_UpdateNoiseState(CPnsData *pPnsData, INT *currentSeed, 140 INT *randomSeed) { 141 /* use pointer because seed has to be 142 same, left and right channel ! */ 143 pPnsData->currentSeed = currentSeed; 144 pPnsData->randomSeed = randomSeed; 145} 146 147/*! 148 \brief Indicates if PNS is used 149 150 The function returns a value indicating whether PNS is used or not 151 acordding to the noise energy 152 153 \return PNS used 154*/ 155int CPns_IsPnsUsed(const CPnsData *pPnsData, const int group, const int band) { 156 unsigned pns_band = group * 16 + band; 157 158 return pPnsData->pnsUsed[pns_band] & (UCHAR)1; 159} 160 161/*! 162 \brief Set correlation 163 164 The function activates the noise correlation between the channel pair 165*/ 166void CPns_SetCorrelation(CPnsData *pPnsData, const int group, const int band, 167 const int outofphase) { 168 CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData; 169 unsigned pns_band = group * 16 + band; 170 171 pInterChannelData->correlated[pns_band] = (outofphase) ? 3 : 1; 172} 173 174/*! 175 \brief Indicates if correlation is used 176 177 The function indicates if the noise correlation between the channel pair 178 is activated 179 180 \return PNS is correlated 181*/ 182static int CPns_IsCorrelated(const CPnsData *pPnsData, const int group, 183 const int band) { 184 CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData; 185 unsigned pns_band = group * 16 + band; 186 187 return (pInterChannelData->correlated[pns_band] & 0x01) ? 1 : 0; 188} 189 190/*! 191 \brief Indicates if correlated out of phase mode is used. 192 193 The function indicates if the noise correlation between the channel pair 194 is activated in out-of-phase mode. 195 196 \return PNS is out-of-phase 197*/ 198static int CPns_IsOutOfPhase(const CPnsData *pPnsData, const int group, 199 const int band) { 200 CPnsInterChannelData *pInterChannelData = pPnsData->pPnsInterChannelData; 201 unsigned pns_band = group * 16 + band; 202 203 return (pInterChannelData->correlated[pns_band] & 0x02) ? 1 : 0; 204} 205 206/*! 207 \brief Read PNS information 208 209 The function reads the PNS information from the bitstream 210*/ 211void CPns_Read(CPnsData *pPnsData, HANDLE_FDK_BITSTREAM bs, 212 const CodeBookDescription *hcb, SHORT *pScaleFactor, 213 UCHAR global_gain, int band, int group /* = 0 */) { 214 int delta; 215 UINT pns_band = group * 16 + band; 216 217 if (pPnsData->PnsActive) { 218 /* Next PNS band case */ 219 delta = CBlock_DecodeHuffmanWord(bs, hcb) - 60; 220 } else { 221 /* First PNS band case */ 222 int noiseStartValue = FDKreadBits(bs, 9); 223 224 delta = noiseStartValue - 256; 225 pPnsData->PnsActive = 1; 226 pPnsData->CurrentEnergy = global_gain - NOISE_OFFSET; 227 } 228 229 pPnsData->CurrentEnergy += delta; 230 pScaleFactor[pns_band] = pPnsData->CurrentEnergy; 231 232 pPnsData->pnsUsed[pns_band] = 1; 233} 234 235/** 236 * \brief Generate a vector of noise of given length. The noise values are 237 * scaled in order to yield a noise energy of 1.0 238 * \param spec pointer to were the noise values will be written to. 239 * \param size amount of noise values to be generated. 240 * \param pRandomState pointer to the state of the random generator being used. 241 * \return exponent of generated noise vector. 242 */ 243static int GenerateRandomVector(FIXP_DBL *RESTRICT spec, int size, 244 int *pRandomState) { 245 int i, invNrg_e = 0, nrg_e = 0; 246 FIXP_DBL invNrg_m, nrg_m = FL2FXCONST_DBL(0.0f); 247 FIXP_DBL *RESTRICT ptr = spec; 248 int randomState = *pRandomState; 249 250#define GEN_NOISE_NRG_SCALE 7 251 252 /* Generate noise and calculate energy. */ 253 for (i = 0; i < size; i++) { 254 randomState = 255 (((INT64)1664525 * randomState) + (INT64)1013904223) & 0xFFFFFFFF; 256 nrg_m = fPow2AddDiv2(nrg_m, (FIXP_DBL)randomState >> GEN_NOISE_NRG_SCALE); 257 *ptr++ = (FIXP_DBL)randomState; 258 } 259 nrg_e = GEN_NOISE_NRG_SCALE * 2 + 1; 260 261 /* weight noise with = 1 / sqrt_nrg; */ 262 invNrg_m = invSqrtNorm2(nrg_m << 1, &invNrg_e); 263 invNrg_e += -((nrg_e - 1) >> 1); 264 265 for (i = size; i--;) { 266 spec[i] = fMult(spec[i], invNrg_m); 267 } 268 269 /* Store random state */ 270 *pRandomState = randomState; 271 272 return invNrg_e; 273} 274 275static void ScaleBand(FIXP_DBL *RESTRICT spec, int size, int scaleFactor, 276 int specScale, int noise_e, int out_of_phase) { 277 int i, shift, sfExponent; 278 FIXP_DBL sfMatissa; 279 280 /* Get gain from scale factor value = 2^(scaleFactor * 0.25) */ 281 sfMatissa = MantissaTable[scaleFactor & 0x03][0]; 282 /* sfExponent = (scaleFactor >> 2) + ExponentTable[scaleFactor & 0x03][0]; */ 283 /* Note: ExponentTable[scaleFactor & 0x03][0] is always 1. */ 284 sfExponent = (scaleFactor >> 2) + 1; 285 286 if (out_of_phase != 0) { 287 sfMatissa = -sfMatissa; 288 } 289 290 /* +1 because of fMultDiv2 below. */ 291 shift = sfExponent - specScale + 1 + noise_e; 292 293 /* Apply gain to noise values */ 294 if (shift >= 0) { 295 shift = fixMin(shift, DFRACT_BITS - 1); 296 for (i = size; i-- != 0;) { 297 spec[i] = fMultDiv2(spec[i], sfMatissa) << shift; 298 } 299 } else { 300 shift = fixMin(-shift, DFRACT_BITS - 1); 301 for (i = size; i-- != 0;) { 302 spec[i] = fMultDiv2(spec[i], sfMatissa) >> shift; 303 } 304 } 305} 306 307/*! 308 \brief Apply PNS 309 310 The function applies PNS (i.e. it generates noise) on the bands 311 flagged as noisy bands 312 313*/ 314void CPns_Apply(const CPnsData *pPnsData, const CIcsInfo *pIcsInfo, 315 SPECTRAL_PTR pSpectrum, const SHORT *pSpecScale, 316 const SHORT *pScaleFactor, 317 const SamplingRateInfo *pSamplingRateInfo, 318 const INT granuleLength, const int channel) { 319 if (pPnsData->PnsActive) { 320 const short *BandOffsets = 321 GetScaleFactorBandOffsets(pIcsInfo, pSamplingRateInfo); 322 323 int ScaleFactorBandsTransmitted = GetScaleFactorBandsTransmitted(pIcsInfo); 324 325 for (int window = 0, group = 0; group < GetWindowGroups(pIcsInfo); 326 group++) { 327 for (int groupwin = 0; groupwin < GetWindowGroupLength(pIcsInfo, group); 328 groupwin++, window++) { 329 FIXP_DBL *spectrum = SPEC(pSpectrum, window, granuleLength); 330 331 for (int band = 0; band < ScaleFactorBandsTransmitted; band++) { 332 if (CPns_IsPnsUsed(pPnsData, group, band)) { 333 UINT pns_band = window * 16 + band; 334 335 int bandWidth = BandOffsets[band + 1] - BandOffsets[band]; 336 int noise_e; 337 338 FDK_ASSERT(bandWidth >= 0); 339 340 if (channel > 0 && CPns_IsCorrelated(pPnsData, group, band)) { 341 noise_e = 342 GenerateRandomVector(spectrum + BandOffsets[band], bandWidth, 343 &pPnsData->randomSeed[pns_band]); 344 } else { 345 pPnsData->randomSeed[pns_band] = *pPnsData->currentSeed; 346 347 noise_e = GenerateRandomVector(spectrum + BandOffsets[band], 348 bandWidth, pPnsData->currentSeed); 349 } 350 351 int outOfPhase = CPns_IsOutOfPhase(pPnsData, group, band); 352 353 ScaleBand(spectrum + BandOffsets[band], bandWidth, 354 pScaleFactor[group * 16 + band], pSpecScale[window], 355 noise_e, outOfPhase); 356 } 357 } 358 } 359 } 360 } 361} 362