1 /* ----------------------------------------------------------------------------- 2 Software License for The Fraunhofer FDK AAC Codec Library for Android 3 4 © Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung 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@iis.fraunhofer.de 93 ----------------------------------------------------------------------------- */ 94 95 /**************************** PCM utility library ****************************** 96 97 Author(s): Matthias Neusinger 98 99 Description: Hard limiter for clipping prevention 100 101 *******************************************************************************/ 102 103 #ifndef LIMITER_H 104 #define LIMITER_H 105 106 #include "common_fix.h" 107 #include "FDK_audio.h" 108 109 #define TDL_ATTACK_DEFAULT_MS (15) /* default attack time in ms */ 110 #define TDL_RELEASE_DEFAULT_MS (50) /* default release time in ms */ 111 112 #define TDL_GAIN_SCALING (15) /* scaling of gain value. */ 113 114 #ifdef __cplusplus 115 extern "C" { 116 #endif 117 118 struct TDLimiter { 119 unsigned int attack; 120 FIXP_DBL attackConst, releaseConst; 121 unsigned int attackMs, releaseMs, maxAttackMs; 122 FIXP_DBL threshold; 123 unsigned int channels, maxChannels; 124 UINT sampleRate, maxSampleRate; 125 FIXP_DBL cor, max; 126 FIXP_DBL* maxBuf; 127 FIXP_DBL* delayBuf; 128 unsigned int maxBufIdx, delayBufIdx; 129 FIXP_DBL smoothState0; 130 FIXP_DBL minGain; 131 132 FIXP_DBL additionalGainPrev; 133 FIXP_DBL additionalGainFilterState; 134 FIXP_DBL additionalGainFilterState1; 135 }; 136 137 typedef enum { 138 TDLIMIT_OK = 0, 139 TDLIMIT_UNKNOWN = -1, 140 141 __error_codes_start = -100, 142 143 TDLIMIT_INVALID_HANDLE, 144 TDLIMIT_INVALID_PARAMETER, 145 146 __error_codes_end 147 } TDLIMITER_ERROR; 148 149 struct TDLimiter; 150 typedef struct TDLimiter* TDLimiterPtr; 151 152 #define PCM_LIM LONG 153 #define FIXP_DBL2PCM_LIM(x) (x) 154 #define PCM_LIM2FIXP_DBL(x) (x) 155 #define PCM_LIM_BITS 32 156 #define FIXP_PCM_LIM FIXP_DBL 157 158 #define SAMPLE_BITS_LIM DFRACT_BITS 159 160 /****************************************************************************** 161 * pcmLimiter_Reset * 162 * limiter: limiter handle * 163 * returns: error code * 164 ******************************************************************************/ 165 TDLIMITER_ERROR pcmLimiter_Reset(TDLimiterPtr limiter); 166 167 /****************************************************************************** 168 * pcmLimiter_Destroy * 169 * limiter: limiter handle * 170 * returns: error code * 171 ******************************************************************************/ 172 TDLIMITER_ERROR pcmLimiter_Destroy(TDLimiterPtr limiter); 173 174 /****************************************************************************** 175 * pcmLimiter_GetDelay * 176 * limiter: limiter handle * 177 * returns: exact delay caused by the limiter in samples per channel * 178 ******************************************************************************/ 179 unsigned int pcmLimiter_GetDelay(TDLimiterPtr limiter); 180 181 /****************************************************************************** 182 * pcmLimiter_GetMaxGainReduction * 183 * limiter: limiter handle * 184 * returns: maximum gain reduction in last processed block in dB * 185 ******************************************************************************/ 186 INT pcmLimiter_GetMaxGainReduction(TDLimiterPtr limiter); 187 188 /****************************************************************************** 189 * pcmLimiter_SetNChannels * 190 * limiter: limiter handle * 191 * nChannels: number of channels ( <= maxChannels specified on create) * 192 * returns: error code * 193 ******************************************************************************/ 194 TDLIMITER_ERROR pcmLimiter_SetNChannels(TDLimiterPtr limiter, 195 unsigned int nChannels); 196 197 /****************************************************************************** 198 * pcmLimiter_SetSampleRate * 199 * limiter: limiter handle * 200 * sampleRate: sampling rate in Hz ( <= maxSampleRate specified on create) * 201 * returns: error code * 202 ******************************************************************************/ 203 TDLIMITER_ERROR pcmLimiter_SetSampleRate(TDLimiterPtr limiter, UINT sampleRate); 204 205 /****************************************************************************** 206 * pcmLimiter_SetAttack * 207 * limiter: limiter handle * 208 * attackMs: attack time in ms ( <= maxAttackMs specified on create) * 209 * returns: error code * 210 ******************************************************************************/ 211 TDLIMITER_ERROR pcmLimiter_SetAttack(TDLimiterPtr limiter, 212 unsigned int attackMs); 213 214 /****************************************************************************** 215 * pcmLimiter_SetRelease * 216 * limiter: limiter handle * 217 * releaseMs: release time in ms * 218 * returns: error code * 219 ******************************************************************************/ 220 TDLIMITER_ERROR pcmLimiter_SetRelease(TDLimiterPtr limiter, 221 unsigned int releaseMs); 222 223 /****************************************************************************** 224 * pcmLimiter_GetLibInfo * 225 * info: pointer to an allocated and initialized LIB_INFO structure * 226 * returns: error code * 227 ******************************************************************************/ 228 TDLIMITER_ERROR pcmLimiter_GetLibInfo(LIB_INFO* info); 229 230 #ifdef __cplusplus 231 } 232 #endif 233 234 /****************************************************************************** 235 * pcmLimiter_Create * 236 * maxAttackMs: maximum and initial attack/lookahead time in milliseconds * 237 * releaseMs: release time in milliseconds (90% time constant) * 238 * threshold: limiting threshold * 239 * maxChannels: maximum and initial number of channels * 240 * maxSampleRate: maximum and initial sampling rate in Hz * 241 * returns: limiter handle * 242 ******************************************************************************/ 243 TDLimiterPtr pcmLimiter_Create(unsigned int maxAttackMs, unsigned int releaseMs, 244 FIXP_DBL threshold, unsigned int maxChannels, 245 UINT maxSampleRate); 246 247 /****************************************************************************** 248 * pcmLimiter_SetThreshold * 249 * limiter: limiter handle * 250 * threshold: limiter threshold * 251 * returns: error code * 252 ******************************************************************************/ 253 TDLIMITER_ERROR pcmLimiter_SetThreshold(TDLimiterPtr limiter, 254 FIXP_DBL threshold); 255 256 /****************************************************************************** 257 * pcmLimiter_Apply * 258 * limiter: limiter handle * 259 * pGain : pointer to gains to be applied to the signal before limiting, * 260 * which are downscaled by TDL_GAIN_SCALING bit. * 261 * These gains are delayed by gain_delay, and smoothed. * 262 * Smoothing is done by a butterworth lowpass filter with a cutoff * 263 * frequency which is fixed with respect to the sampling rate. * 264 * It is a substitute for the smoothing due to windowing and * 265 * overlap/add, if a gain is applied in frequency domain. * 266 * gain_scale: pointer to scaling exponents to be applied to the signal before * 267 * limiting, without delay and without smoothing * 268 * gain_size: number of elements in pGain, currently restricted to 1 * 269 * gain_delay: delay [samples] with which the gains in pGain shall be applied * 270 * gain_delay <= nSamples * 271 * samples: input/output buffer containing interleaved samples * 272 * precision of output will be DFRACT_BITS-TDL_GAIN_SCALING bits * 273 * nSamples: number of samples per channel * 274 * returns: error code * 275 ******************************************************************************/ 276 TDLIMITER_ERROR pcmLimiter_Apply(TDLimiterPtr limiter, PCM_LIM* samplesIn, 277 INT_PCM* samplesOut, FIXP_DBL* pGain, 278 const INT* gain_scale, const UINT gain_size, 279 const UINT gain_delay, const UINT nSamples); 280 281 #endif /* #ifndef LIMITER_H */ 282