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