| |
| /* ----------------------------------------------------------------------------------------------------------- |
| Software License for The Fraunhofer FDK AAC Codec Library for Android |
| |
| © Copyright 1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. |
| All rights reserved. |
| |
| 1. INTRODUCTION |
| The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements |
| the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio. |
| This FDK AAC Codec software is intended to be used on a wide variety of Android devices. |
| |
| AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual |
| audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by |
| independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part |
| of the MPEG specifications. |
| |
| Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer) |
| may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners |
| individually for the purpose of encoding or decoding bit streams in products that are compliant with |
| the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license |
| these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec |
| software may already be covered under those patent licenses when it is used for those licensed purposes only. |
| |
| Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality, |
| are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional |
| applications information and documentation. |
| |
| 2. COPYRIGHT LICENSE |
| |
| Redistribution and use in source and binary forms, with or without modification, are permitted without |
| payment of copyright license fees provided that you satisfy the following conditions: |
| |
| You must retain the complete text of this software license in redistributions of the FDK AAC Codec or |
| your modifications thereto in source code form. |
| |
| You must retain the complete text of this software license in the documentation and/or other materials |
| provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form. |
| You must make available free of charge copies of the complete source code of the FDK AAC Codec and your |
| modifications thereto to recipients of copies in binary form. |
| |
| The name of Fraunhofer may not be used to endorse or promote products derived from this library without |
| prior written permission. |
| |
| You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec |
| software or your modifications thereto. |
| |
| Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software |
| and the date of any change. For modified versions of the FDK AAC Codec, the term |
| "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term |
| "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android." |
| |
| 3. NO PATENT LICENSE |
| |
| NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer, |
| ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with |
| respect to this software. |
| |
| You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized |
| by appropriate patent licenses. |
| |
| 4. DISCLAIMER |
| |
| This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors |
| "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties |
| of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR |
| CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages, |
| including but not limited to procurement of substitute goods or services; loss of use, data, or profits, |
| or business interruption, however caused and on any theory of liability, whether in contract, strict |
| liability, or tort (including negligence), arising in any way out of the use of this software, even if |
| advised of the possibility of such damage. |
| |
| 5. CONTACT INFORMATION |
| |
| Fraunhofer Institute for Integrated Circuits IIS |
| Attention: Audio and Multimedia Departments - FDK AAC LL |
| Am Wolfsmantel 33 |
| 91058 Erlangen, Germany |
| |
| www.iis.fraunhofer.de/amm |
| amm-info@iis.fraunhofer.de |
| ----------------------------------------------------------------------------------------------------------- */ |
| |
| /************************ FDK PCM postprocessor module ********************* |
| |
| Author(s): Matthias Neusinger |
| Description: Hard limiter for clipping prevention |
| |
| *******************************************************************************/ |
| |
| #ifndef _LIMITER_H_ |
| #define _LIMITER_H_ |
| |
| |
| #include "common_fix.h" |
| |
| #define TDL_ATTACK_DEFAULT_MS (15) /* default attack time in ms */ |
| #define TDL_RELEASE_DEFAULT_MS (50) /* default release time in ms */ |
| |
| #define TDL_GAIN_SCALING (15) /* scaling of gain value. */ |
| |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| typedef enum { |
| TDLIMIT_OK = 0, |
| |
| __error_codes_start = -100, |
| |
| TDLIMIT_INVALID_HANDLE, |
| TDLIMIT_INVALID_PARAMETER, |
| |
| __error_codes_end |
| } TDLIMITER_ERROR; |
| |
| struct TDLimiter; |
| typedef struct TDLimiter* TDLimiterPtr; |
| |
| /****************************************************************************** |
| * createLimiter * |
| * maxAttackMs: maximum and initial attack/lookahead time in milliseconds * |
| * releaseMs: release time in milliseconds (90% time constant) * |
| * threshold: limiting threshold * |
| * maxChannels: maximum and initial number of channels * |
| * maxSampleRate: maximum and initial sampling rate in Hz * |
| * returns: limiter handle * |
| ******************************************************************************/ |
| TDLimiterPtr createLimiter(unsigned int maxAttackMs, |
| unsigned int releaseMs, |
| INT_PCM threshold, |
| unsigned int maxChannels, |
| unsigned int maxSampleRate); |
| |
| |
| /****************************************************************************** |
| * resetLimiter * |
| * limiter: limiter handle * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR resetLimiter(TDLimiterPtr limiter); |
| |
| |
| /****************************************************************************** |
| * destroyLimiter * |
| * limiter: limiter handle * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR destroyLimiter(TDLimiterPtr limiter); |
| |
| /****************************************************************************** |
| * applyLimiter * |
| * limiter: limiter handle * |
| * pGain : pointer to gains to be applied to the signal before limiting, * |
| * which are downscaled by TDL_GAIN_SCALING bit. * |
| * These gains are delayed by gain_delay, and smoothed. * |
| * Smoothing is done by a butterworth lowpass filter with a cutoff * |
| * frequency which is fixed with respect to the sampling rate. * |
| * It is a substitute for the smoothing due to windowing and * |
| * overlap/add, if a gain is applied in frequency domain. * |
| * gain_scale: pointer to scaling exponents to be applied to the signal before * |
| * limiting, without delay and without smoothing * |
| * gain_size: number of elements in pGain, currently restricted to 1 * |
| * gain_delay: delay [samples] with which the gains in pGain shall be applied * |
| * gain_delay <= nSamples * |
| * samples: input/output buffer containing interleaved samples * |
| * precision of output will be DFRACT_BITS-TDL_GAIN_SCALING bits * |
| * nSamples: number of samples per channel * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR applyLimiter(TDLimiterPtr limiter, |
| INT_PCM* samples, |
| FIXP_DBL* pGain, |
| const INT* gain_scale, |
| const UINT gain_size, |
| const UINT gain_delay, |
| const UINT nSamples); |
| |
| /****************************************************************************** |
| * getLimiterDelay * |
| * limiter: limiter handle * |
| * returns: exact delay caused by the limiter in samples * |
| ******************************************************************************/ |
| unsigned int getLimiterDelay(TDLimiterPtr limiter); |
| |
| /****************************************************************************** |
| * setLimiterNChannels * |
| * limiter: limiter handle * |
| * nChannels: number of channels ( <= maxChannels specified on create) * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR setLimiterNChannels(TDLimiterPtr limiter, unsigned int nChannels); |
| |
| /****************************************************************************** |
| * setLimiterSampleRate * |
| * limiter: limiter handle * |
| * sampleRate: sampling rate in Hz ( <= maxSampleRate specified on create) * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR setLimiterSampleRate(TDLimiterPtr limiter, unsigned int sampleRate); |
| |
| /****************************************************************************** |
| * setLimiterAttack * |
| * limiter: limiter handle * |
| * attackMs: attack time in ms ( <= maxAttackMs specified on create) * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR setLimiterAttack(TDLimiterPtr limiter, unsigned int attackMs); |
| |
| /****************************************************************************** |
| * setLimiterRelease * |
| * limiter: limiter handle * |
| * releaseMs: release time in ms * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR setLimiterRelease(TDLimiterPtr limiter, unsigned int releaseMs); |
| |
| /****************************************************************************** |
| * setLimiterThreshold * |
| * limiter: limiter handle * |
| * threshold: limiter threshold * |
| * returns: error code * |
| ******************************************************************************/ |
| TDLIMITER_ERROR setLimiterThreshold(TDLimiterPtr limiter, INT_PCM threshold); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| |
| #endif //#ifndef _LIMITER_H_ |
