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219 lines
9.7 KiB
219 lines
9.7 KiB
/* -----------------------------------------------------------------------------
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Software License for The Fraunhofer FDK AAC Codec Library for Android
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© Copyright 1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
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Forschung e.V. 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
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that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
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scheme for digital audio. This FDK AAC Codec software is intended to be used on
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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
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general perceptual audio codecs. AAC-ELD is considered the best-performing
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full-bandwidth communications codec by independent studies and is widely
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deployed. AAC has been standardized by ISO and IEC as part of the MPEG
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specifications.
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Patent licenses for necessary patent claims for the FDK AAC Codec (including
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those of Fraunhofer) may be obtained through Via Licensing
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(www.vialicensing.com) or through the respective patent owners individually for
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the purpose of encoding or decoding bit streams in products that are compliant
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with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
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Android devices already license these patent claims through Via Licensing or
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directly from the patent owners, and therefore FDK AAC Codec software may
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already be covered under those patent licenses when it is used for those
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licensed purposes only.
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Commercially-licensed AAC software libraries, including floating-point versions
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with enhanced sound quality, are also available from Fraunhofer. Users are
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encouraged to check the Fraunhofer website for additional applications
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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,
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are permitted without payment of copyright license fees provided that you
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satisfy the following conditions:
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You must retain the complete text of this software license in redistributions of
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the FDK AAC Codec or your modifications thereto in source code form.
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You must retain the complete text of this software license in the documentation
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and/or other materials provided with redistributions of the FDK AAC Codec or
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your modifications thereto in binary form. You must make available free of
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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
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from this library without prior written permission.
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You may not charge copyright license fees for anyone to use, copy or distribute
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the FDK AAC Codec software or your modifications thereto.
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Your modified versions of the FDK AAC Codec must carry prominent notices stating
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that you changed the software and the date of any change. For modified versions
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of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
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must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
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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
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limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
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Fraunhofer provides no warranty of patent non-infringement with respect to this
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software.
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You may use this FDK AAC Codec software or modifications thereto only for
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purposes that are authorized 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
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holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
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including but not limited to the implied warranties of merchantability and
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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,
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or consequential damages, including but not limited to procurement of substitute
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goods or services; loss of use, data, or profits, or business interruption,
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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
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this software, even if 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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/******************* Library for basic calculation routines ********************
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Author(s): Manuel Jander
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Description: LPC related functions
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*******************************************************************************/
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#ifndef FDK_LPC_H
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#define FDK_LPC_H
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#include "common_fix.h"
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#define LPC_MAX_ORDER 24
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/*
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* Experimental solution for lattice filter substitution.
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* LPC_SYNTHESIS_IIR macro must be activated in aacdec_tns.cpp.
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* When LPC_SYNTHESIS_IIR enabled, there will be a substitution of the default
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* lpc synthesis lattice filter by an IIR synthesis filter (with a conversionof
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* the filter coefs). LPC_TNS related macros are intended to implement the data
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* types used by the CLpc_Synthesis variant which is used for this solution.
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* */
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/* #define LPC_TNS_LOWER_PRECISION */
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typedef FIXP_DBL FIXP_LPC_TNS;
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#define FX_DBL2FX_LPC_TNS(x) (x)
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#define FX_DBL2FXCONST_LPC_TNS(x) (x)
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#define FX_LPC_TNS2FX_DBL(x) (x)
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#define FL2FXCONST_LPC_TNS(val) FL2FXCONST_DBL(val)
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#define MAXVAL_LPC_TNS MAXVAL_DBL
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typedef FIXP_SGL FIXP_LPC;
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#define FX_DBL2FX_LPC(x) FX_DBL2FX_SGL((FIXP_DBL)(x))
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#define FX_DBL2FXCONST_LPC(x) FX_DBL2FXCONST_SGL(x)
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#define FX_LPC2FX_DBL(x) FX_SGL2FX_DBL(x)
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#define FL2FXCONST_LPC(val) FL2FXCONST_SGL(val)
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#define MAXVAL_LPC MAXVAL_SGL
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/**
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* \brief Obtain residual signal through LPC analysis.
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* \param signal pointer to buffer holding signal to be analysed. Residual is
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* returned there (in place)
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* \param signal_size the size of the input data in pData
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* \param lpcCoeff_m the LPC filter coefficient mantissas
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* \param lpcCoeff_e the LPC filter coefficient exponent
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* \param order the LPC filter order (size of coeff)
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* \param filtState Pointer to state buffer of size order
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* \param filtStateIndex pointer to state index storage
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*/
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void CLpc_Analysis(FIXP_DBL signal[], const int signal_size,
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const FIXP_LPC lpcCoeff_m[], const int lpcCoeff_e,
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const int order, FIXP_DBL *filtState, int *filtStateIndex);
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/**
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* \brief Synthesize signal fom residual through LPC synthesis, using LP
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* coefficients.
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* \param signal pointer to buffer holding the residual signal. The synthesis is
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* returned there (in place)
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* \param signal_size the size of the input data in pData
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* \param inc buffer traversal increment for signal
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* \param coeff the LPC filter coefficients
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* \param coeff_e exponent of coeff
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* \param order the LPC filter order (size of coeff)
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* \param state state buffer of size LPC_MAX_ORDER
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* \param pStateIndex pointer to state index storage
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*/
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void CLpc_Synthesis(FIXP_DBL *signal, const int signal_size, const int signal_e,
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const int inc, const FIXP_LPC_TNS *lpcCoeff_m,
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const int lpcCoeff_e, const int order, FIXP_DBL *state,
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int *pStateIndex);
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void CLpc_Synthesis(FIXP_DBL *signal, const int signal_size, const int signal_e,
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const int inc, const FIXP_LPC coeff[], const int coeff_e,
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const int order, FIXP_DBL *filtState, int *pStateIndex);
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/**
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* \brief Synthesize signal fom residual through LPC synthesis, using ParCor
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* coefficients. The algorithm assumes a filter gain of max 1.0. If the filter
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* gain is higher, this must be accounted into the values of signal_e
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* and/or signal_e_out to avoid overflows.
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* \param signal pointer to buffer holding the residual signal. The synthesis is
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* returned there (in place)
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* \param signal_size the size of the input data in pData
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* \param inc buffer traversal increment for signal
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* \param coeff the LPC filter coefficients
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* \param coeff_e exponent of coeff
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* \param order the LPC filter order (size of coeff)
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* \param state state buffer of size LPC_MAX_ORDER
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*/
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void CLpc_SynthesisLattice(FIXP_DBL *signal, const int signal_size,
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const int signal_e, const int signal_e_out,
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const int inc, const FIXP_SGL *coeff,
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const int order, FIXP_DBL *state);
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void CLpc_SynthesisLattice(FIXP_DBL *RESTRICT signal, const int signal_size,
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const int signal_e, const int signal_e_out,
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const int inc, const FIXP_DBL *RESTRICT coeff,
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const int order, FIXP_DBL *RESTRICT state);
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/**
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* \brief
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*/
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INT CLpc_ParcorToLpc(const FIXP_LPC_TNS reflCoeff[], FIXP_LPC_TNS LpcCoeff[],
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INT numOfCoeff, FIXP_DBL workBuffer[]);
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INT CLpc_ParcorToLpc(const FIXP_LPC reflCoeff[], FIXP_LPC LpcCoeff[],
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const int numOfCoeff, FIXP_DBL workBuffer[]);
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/**
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* \brief Calculate ParCor (Partial autoCorrelation, reflection) coefficients
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* from autocorrelation coefficients using the Schur algorithm (instead of
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* Levinson Durbin).
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* \param acorr order+1 autocorrelation coefficients
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* \param reflCoeff output reflection /ParCor coefficients. The first
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* coefficient which is always 1.0 is ommitted.
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* \param order number of acorr / reflCoeff coefficients.
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* \param pPredictionGain_m prediction gain mantissa
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* \param pPredictionGain_e prediction gain exponent
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*/
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void CLpc_AutoToParcor(FIXP_DBL acorr[], const int acorr_e,
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FIXP_LPC reflCoeff[], const int order,
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FIXP_DBL *pPredictionGain_m, INT *pPredictionGain_e);
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#endif /* FDK_LPC_H */
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