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 /************************ FDK PCM postprocessor module ********************* 85 86 Author(s): Matthias Neusinger 87 Description: Hard limiter for clipping prevention 88 89 *******************************************************************************/ 90 91 #ifndef _LIMITER_H_ 92 #define _LIMITER_H_ 93 94 95 #include "common_fix.h" 96 97 #define TDL_ATTACK_DEFAULT_MS (15) /* default attack time in ms */ 98 #define TDL_RELEASE_DEFAULT_MS (50) /* default release time in ms */ 99 100 #define TDL_GAIN_SCALING (15) /* scaling of gain value. */ 101 102 103 #ifdef __cplusplus 104 extern "C" { 105 #endif 106 107 108 typedef enum { 109 TDLIMIT_OK = 0, 110 111 __error_codes_start = -100, 112 113 TDLIMIT_INVALID_HANDLE, 114 TDLIMIT_INVALID_PARAMETER, 115 116 __error_codes_end 117 } TDLIMITER_ERROR; 118 119 struct TDLimiter; 120 typedef struct TDLimiter* TDLimiterPtr; 121 122 /****************************************************************************** 123 * createLimiter * 124 * maxAttackMs: maximum and initial attack/lookahead time in milliseconds * 125 * releaseMs: release time in milliseconds (90% time constant) * 126 * threshold: limiting threshold * 127 * maxChannels: maximum and initial number of channels * 128 * maxSampleRate: maximum and initial sampling rate in Hz * 129 * returns: limiter handle * 130 ******************************************************************************/ 131 TDLimiterPtr createLimiter(unsigned int maxAttackMs, 132 unsigned int releaseMs, 133 INT_PCM threshold, 134 unsigned int maxChannels, 135 unsigned int maxSampleRate); 136 137 138 /****************************************************************************** 139 * resetLimiter * 140 * limiter: limiter handle * 141 * returns: error code * 142 ******************************************************************************/ 143 TDLIMITER_ERROR resetLimiter(TDLimiterPtr limiter); 144 145 146 /****************************************************************************** 147 * destroyLimiter * 148 * limiter: limiter handle * 149 * returns: error code * 150 ******************************************************************************/ 151 TDLIMITER_ERROR destroyLimiter(TDLimiterPtr limiter); 152 153 /****************************************************************************** 154 * applyLimiter * 155 * limiter: limiter handle * 156 * pGain : pointer to gains to be applied to the signal before limiting, * 157 * which are downscaled by TDL_GAIN_SCALING bit. * 158 * These gains are delayed by gain_delay, and smoothed. * 159 * Smoothing is done by a butterworth lowpass filter with a cutoff * 160 * frequency which is fixed with respect to the sampling rate. * 161 * It is a substitute for the smoothing due to windowing and * 162 * overlap/add, if a gain is applied in frequency domain. * 163 * gain_scale: pointer to scaling exponents to be applied to the signal before * 164 * limiting, without delay and without smoothing * 165 * gain_size: number of elements in pGain, currently restricted to 1 * 166 * gain_delay: delay [samples] with which the gains in pGain shall be applied * 167 * gain_delay <= nSamples * 168 * samples: input/output buffer containing interleaved samples * 169 * precision of output will be DFRACT_BITS-TDL_GAIN_SCALING bits * 170 * nSamples: number of samples per channel * 171 * returns: error code * 172 ******************************************************************************/ 173 TDLIMITER_ERROR applyLimiter(TDLimiterPtr limiter, 174 INT_PCM* samples, 175 FIXP_DBL* pGain, 176 const INT* gain_scale, 177 const UINT gain_size, 178 const UINT gain_delay, 179 const UINT nSamples); 180 181 /****************************************************************************** 182 * getLimiterDelay * 183 * limiter: limiter handle * 184 * returns: exact delay caused by the limiter in samples * 185 ******************************************************************************/ 186 unsigned int getLimiterDelay(TDLimiterPtr limiter); 187 188 /****************************************************************************** 189 * setLimiterNChannels * 190 * limiter: limiter handle * 191 * nChannels: number of channels ( <= maxChannels specified on create) * 192 * returns: error code * 193 ******************************************************************************/ 194 TDLIMITER_ERROR setLimiterNChannels(TDLimiterPtr limiter, unsigned int nChannels); 195 196 /****************************************************************************** 197 * setLimiterSampleRate * 198 * limiter: limiter handle * 199 * sampleRate: sampling rate in Hz ( <= maxSampleRate specified on create) * 200 * returns: error code * 201 ******************************************************************************/ 202 TDLIMITER_ERROR setLimiterSampleRate(TDLimiterPtr limiter, unsigned int sampleRate); 203 204 /****************************************************************************** 205 * setLimiterAttack * 206 * limiter: limiter handle * 207 * attackMs: attack time in ms ( <= maxAttackMs specified on create) * 208 * returns: error code * 209 ******************************************************************************/ 210 TDLIMITER_ERROR setLimiterAttack(TDLimiterPtr limiter, unsigned int attackMs); 211 212 /****************************************************************************** 213 * setLimiterRelease * 214 * limiter: limiter handle * 215 * releaseMs: release time in ms * 216 * returns: error code * 217 ******************************************************************************/ 218 TDLIMITER_ERROR setLimiterRelease(TDLimiterPtr limiter, unsigned int releaseMs); 219 220 /****************************************************************************** 221 * setLimiterThreshold * 222 * limiter: limiter handle * 223 * threshold: limiter threshold * 224 * returns: error code * 225 ******************************************************************************/ 226 TDLIMITER_ERROR setLimiterThreshold(TDLimiterPtr limiter, INT_PCM threshold); 227 228 #ifdef __cplusplus 229 } 230 #endif 231 232 233 #endif //#ifndef _LIMITER_H_ 234
