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/**************************** 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 115extern "C" { 116#endif 117 118struct 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 137typedef 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 149struct TDLimiter; 150typedef 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 ******************************************************************************/ 165TDLIMITER_ERROR pcmLimiter_Reset(TDLimiterPtr limiter); 166 167/****************************************************************************** 168 * pcmLimiter_Destroy * 169 * limiter: limiter handle * 170 * returns: error code * 171 ******************************************************************************/ 172TDLIMITER_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 ******************************************************************************/ 179unsigned 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 ******************************************************************************/ 186INT 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 ******************************************************************************/ 194TDLIMITER_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 ******************************************************************************/ 203TDLIMITER_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 ******************************************************************************/ 211TDLIMITER_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 ******************************************************************************/ 220TDLIMITER_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 ******************************************************************************/ 228TDLIMITER_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 ******************************************************************************/ 243TDLimiterPtr 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 ******************************************************************************/ 253TDLIMITER_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 ******************************************************************************/ 276TDLIMITER_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